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c63b6a437e
My type ascription Oh rip it out Ah If you think we live too much then You can sacrifice diagnostics Don't mix your garbage Into my syntax So many weird hacks keep diagnostics alive Yet I don't even step outside So many bad diagnostics keep tyasc alive Yet tyasc doesn't even bother to survive!
3272 lines
133 KiB
Rust
3272 lines
133 KiB
Rust
use super::diagnostics::SnapshotParser;
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use super::pat::{CommaRecoveryMode, Expected, RecoverColon, RecoverComma};
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use super::ty::{AllowPlus, RecoverQPath, RecoverReturnSign};
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use super::{
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AttrWrapper, BlockMode, ClosureSpans, ForceCollect, Parser, PathStyle, Restrictions,
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SemiColonMode, SeqSep, TokenExpectType, TokenType, TrailingToken,
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};
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use crate::errors;
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use crate::maybe_recover_from_interpolated_ty_qpath;
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use ast::{Path, PathSegment};
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use core::mem;
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use rustc_ast::ptr::P;
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use rustc_ast::token::{self, Delimiter, Token, TokenKind};
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use rustc_ast::tokenstream::Spacing;
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use rustc_ast::util::case::Case;
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use rustc_ast::util::classify;
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use rustc_ast::util::parser::{prec_let_scrutinee_needs_par, AssocOp, Fixity};
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use rustc_ast::visit::Visitor;
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use rustc_ast::{self as ast, AttrStyle, AttrVec, CaptureBy, ExprField, UnOp, DUMMY_NODE_ID};
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use rustc_ast::{AnonConst, BinOp, BinOpKind, FnDecl, FnRetTy, MacCall, Param, Ty, TyKind};
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use rustc_ast::{Arm, Async, BlockCheckMode, Expr, ExprKind, Label, Movability, RangeLimits};
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use rustc_ast::{ClosureBinder, MetaItemLit, StmtKind};
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use rustc_ast_pretty::pprust;
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use rustc_errors::{
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AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, IntoDiagnostic,
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PResult, StashKey,
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};
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use rustc_session::errors::{report_lit_error, ExprParenthesesNeeded};
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use rustc_session::lint::builtin::BREAK_WITH_LABEL_AND_LOOP;
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use rustc_session::lint::BuiltinLintDiagnostics;
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use rustc_span::source_map::{self, Span, Spanned};
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use rustc_span::symbol::kw::PathRoot;
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use rustc_span::symbol::{kw, sym, Ident, Symbol};
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use rustc_span::{BytePos, Pos};
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use thin_vec::{thin_vec, ThinVec};
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/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
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/// dropped into the token stream, which happens while parsing the result of
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/// macro expansion). Placement of these is not as complex as I feared it would
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/// be. The important thing is to make sure that lookahead doesn't balk at
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/// `token::Interpolated` tokens.
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macro_rules! maybe_whole_expr {
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($p:expr) => {
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if let token::Interpolated(nt) = &$p.token.kind {
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match &**nt {
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token::NtExpr(e) | token::NtLiteral(e) => {
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let e = e.clone();
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$p.bump();
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return Ok(e);
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}
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token::NtPath(path) => {
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let path = (**path).clone();
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$p.bump();
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return Ok($p.mk_expr($p.prev_token.span, ExprKind::Path(None, path)));
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}
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token::NtBlock(block) => {
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let block = block.clone();
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$p.bump();
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return Ok($p.mk_expr($p.prev_token.span, ExprKind::Block(block, None)));
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}
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_ => {}
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};
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}
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};
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}
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#[derive(Debug)]
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pub(super) enum LhsExpr {
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NotYetParsed,
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AttributesParsed(AttrWrapper),
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AlreadyParsed { expr: P<Expr>, starts_statement: bool },
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}
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impl From<Option<AttrWrapper>> for LhsExpr {
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/// Converts `Some(attrs)` into `LhsExpr::AttributesParsed(attrs)`
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/// and `None` into `LhsExpr::NotYetParsed`.
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///
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/// This conversion does not allocate.
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fn from(o: Option<AttrWrapper>) -> Self {
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if let Some(attrs) = o { LhsExpr::AttributesParsed(attrs) } else { LhsExpr::NotYetParsed }
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}
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}
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impl From<P<Expr>> for LhsExpr {
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/// Converts the `expr: P<Expr>` into `LhsExpr::AlreadyParsed { expr, starts_statement: false }`.
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///
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/// This conversion does not allocate.
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fn from(expr: P<Expr>) -> Self {
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LhsExpr::AlreadyParsed { expr, starts_statement: false }
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}
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}
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impl<'a> Parser<'a> {
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/// Parses an expression.
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#[inline]
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pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
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self.current_closure.take();
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self.parse_expr_res(Restrictions::empty(), None)
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}
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/// Parses an expression, forcing tokens to be collected
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pub fn parse_expr_force_collect(&mut self) -> PResult<'a, P<Expr>> {
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self.collect_tokens_no_attrs(|this| this.parse_expr())
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}
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pub fn parse_expr_anon_const(&mut self) -> PResult<'a, AnonConst> {
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self.parse_expr().map(|value| AnonConst { id: DUMMY_NODE_ID, value })
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}
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fn parse_expr_catch_underscore(&mut self) -> PResult<'a, P<Expr>> {
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match self.parse_expr() {
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Ok(expr) => Ok(expr),
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Err(mut err) => match self.token.ident() {
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Some((Ident { name: kw::Underscore, .. }, false))
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if self.may_recover() && self.look_ahead(1, |t| t == &token::Comma) =>
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{
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// Special-case handling of `foo(_, _, _)`
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err.emit();
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self.bump();
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Ok(self.mk_expr(self.prev_token.span, ExprKind::Err))
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}
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_ => Err(err),
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},
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}
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}
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/// Parses a sequence of expressions delimited by parentheses.
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fn parse_expr_paren_seq(&mut self) -> PResult<'a, ThinVec<P<Expr>>> {
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self.parse_paren_comma_seq(|p| p.parse_expr_catch_underscore()).map(|(r, _)| r)
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}
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/// Parses an expression, subject to the given restrictions.
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#[inline]
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pub(super) fn parse_expr_res(
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&mut self,
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r: Restrictions,
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already_parsed_attrs: Option<AttrWrapper>,
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) -> PResult<'a, P<Expr>> {
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self.with_res(r, |this| this.parse_expr_assoc(already_parsed_attrs))
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}
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/// Parses an associative expression.
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///
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/// This parses an expression accounting for associativity and precedence of the operators in
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/// the expression.
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#[inline]
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fn parse_expr_assoc(
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&mut self,
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already_parsed_attrs: Option<AttrWrapper>,
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) -> PResult<'a, P<Expr>> {
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self.parse_expr_assoc_with(0, already_parsed_attrs.into())
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}
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/// Parses an associative expression with operators of at least `min_prec` precedence.
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pub(super) fn parse_expr_assoc_with(
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&mut self,
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min_prec: usize,
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lhs: LhsExpr,
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) -> PResult<'a, P<Expr>> {
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let mut starts_stmt = false;
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let mut lhs = if let LhsExpr::AlreadyParsed { expr, starts_statement } = lhs {
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starts_stmt = starts_statement;
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expr
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} else {
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let attrs = match lhs {
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LhsExpr::AttributesParsed(attrs) => Some(attrs),
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_ => None,
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};
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if self.token.is_range_separator() {
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return self.parse_expr_prefix_range(attrs);
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} else {
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self.parse_expr_prefix(attrs)?
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}
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};
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if !self.should_continue_as_assoc_expr(&lhs) {
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return Ok(lhs);
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}
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self.expected_tokens.push(TokenType::Operator);
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while let Some(op) = self.check_assoc_op() {
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// Adjust the span for interpolated LHS to point to the `$lhs` token
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// and not to what it refers to.
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let lhs_span = match self.prev_token.kind {
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TokenKind::Interpolated(..) => self.prev_token.span,
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_ => lhs.span,
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};
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let cur_op_span = self.token.span;
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let restrictions = if op.node.is_assign_like() {
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self.restrictions & Restrictions::NO_STRUCT_LITERAL
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} else {
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self.restrictions
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};
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let prec = op.node.precedence();
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if prec < min_prec {
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break;
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}
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// Check for deprecated `...` syntax
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if self.token == token::DotDotDot && op.node == AssocOp::DotDotEq {
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self.err_dotdotdot_syntax(self.token.span);
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}
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if self.token == token::LArrow {
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self.err_larrow_operator(self.token.span);
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}
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self.bump();
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if op.node.is_comparison() {
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if let Some(expr) = self.check_no_chained_comparison(&lhs, &op)? {
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return Ok(expr);
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}
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}
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// Look for JS' `===` and `!==` and recover
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if (op.node == AssocOp::Equal || op.node == AssocOp::NotEqual)
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&& self.token.kind == token::Eq
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&& self.prev_token.span.hi() == self.token.span.lo()
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{
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let sp = op.span.to(self.token.span);
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let sugg = match op.node {
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AssocOp::Equal => "==",
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AssocOp::NotEqual => "!=",
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_ => unreachable!(),
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}
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.into();
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let invalid = format!("{}=", &sugg);
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self.sess.emit_err(errors::InvalidComparisonOperator {
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span: sp,
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invalid: invalid.clone(),
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sub: errors::InvalidComparisonOperatorSub::Correctable {
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span: sp,
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invalid,
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correct: sugg,
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},
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});
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self.bump();
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}
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// Look for PHP's `<>` and recover
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if op.node == AssocOp::Less
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&& self.token.kind == token::Gt
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&& self.prev_token.span.hi() == self.token.span.lo()
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{
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let sp = op.span.to(self.token.span);
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self.sess.emit_err(errors::InvalidComparisonOperator {
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span: sp,
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invalid: "<>".into(),
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sub: errors::InvalidComparisonOperatorSub::Correctable {
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span: sp,
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invalid: "<>".into(),
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correct: "!=".into(),
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},
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});
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self.bump();
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}
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// Look for C++'s `<=>` and recover
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if op.node == AssocOp::LessEqual
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&& self.token.kind == token::Gt
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&& self.prev_token.span.hi() == self.token.span.lo()
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{
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let sp = op.span.to(self.token.span);
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self.sess.emit_err(errors::InvalidComparisonOperator {
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span: sp,
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invalid: "<=>".into(),
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sub: errors::InvalidComparisonOperatorSub::Spaceship(sp),
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});
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self.bump();
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}
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if self.prev_token == token::BinOp(token::Plus)
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&& self.token == token::BinOp(token::Plus)
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&& self.prev_token.span.between(self.token.span).is_empty()
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{
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let op_span = self.prev_token.span.to(self.token.span);
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// Eat the second `+`
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self.bump();
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lhs = self.recover_from_postfix_increment(lhs, op_span, starts_stmt)?;
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continue;
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}
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if self.prev_token == token::BinOp(token::Minus)
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&& self.token == token::BinOp(token::Minus)
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&& self.prev_token.span.between(self.token.span).is_empty()
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&& !self.look_ahead(1, |tok| tok.can_begin_expr())
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{
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let op_span = self.prev_token.span.to(self.token.span);
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// Eat the second `-`
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self.bump();
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lhs = self.recover_from_postfix_decrement(lhs, op_span, starts_stmt)?;
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continue;
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}
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// Special cases:
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if op.node == AssocOp::As {
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lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?;
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continue;
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} else if op.node == AssocOp::DotDot || op.node == AssocOp::DotDotEq {
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// If we didn't have to handle `x..`/`x..=`, it would be pretty easy to
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// generalise it to the Fixity::None code.
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lhs = self.parse_expr_range(prec, lhs, op.node, cur_op_span)?;
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break;
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}
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let op = op.node;
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// Special cases:
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if op == AssocOp::As {
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lhs = self.parse_assoc_op_cast(lhs, lhs_span, ExprKind::Cast)?;
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continue;
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} else if op == AssocOp::DotDot || op == AssocOp::DotDotEq {
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// If we didn't have to handle `x..`/`x..=`, it would be pretty easy to
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// generalise it to the Fixity::None code.
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lhs = self.parse_expr_range(prec, lhs, op, cur_op_span)?;
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break;
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}
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let fixity = op.fixity();
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let prec_adjustment = match fixity {
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Fixity::Right => 0,
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Fixity::Left => 1,
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// We currently have no non-associative operators that are not handled above by
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// the special cases. The code is here only for future convenience.
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Fixity::None => 1,
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};
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let rhs = self.with_res(restrictions - Restrictions::STMT_EXPR, |this| {
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this.parse_expr_assoc_with(prec + prec_adjustment, LhsExpr::NotYetParsed)
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})?;
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let span = self.mk_expr_sp(&lhs, lhs_span, rhs.span);
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lhs = match op {
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AssocOp::Add
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| AssocOp::Subtract
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| AssocOp::Multiply
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| AssocOp::Divide
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| AssocOp::Modulus
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| AssocOp::LAnd
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| AssocOp::LOr
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| AssocOp::BitXor
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| AssocOp::BitAnd
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| AssocOp::BitOr
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| AssocOp::ShiftLeft
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| AssocOp::ShiftRight
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| AssocOp::Equal
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| AssocOp::Less
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| AssocOp::LessEqual
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| AssocOp::NotEqual
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| AssocOp::Greater
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| AssocOp::GreaterEqual => {
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let ast_op = op.to_ast_binop().unwrap();
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let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
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self.mk_expr(span, binary)
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}
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AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs, cur_op_span)),
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AssocOp::AssignOp(k) => {
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let aop = match k {
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token::Plus => BinOpKind::Add,
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token::Minus => BinOpKind::Sub,
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token::Star => BinOpKind::Mul,
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token::Slash => BinOpKind::Div,
|
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token::Percent => BinOpKind::Rem,
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token::Caret => BinOpKind::BitXor,
|
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token::And => BinOpKind::BitAnd,
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token::Or => BinOpKind::BitOr,
|
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token::Shl => BinOpKind::Shl,
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token::Shr => BinOpKind::Shr,
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};
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let aopexpr = self.mk_assign_op(source_map::respan(cur_op_span, aop), lhs, rhs);
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self.mk_expr(span, aopexpr)
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}
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AssocOp::As | AssocOp::DotDot | AssocOp::DotDotEq => {
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self.span_bug(span, "AssocOp should have been handled by special case")
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}
|
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};
|
|
|
|
if let Fixity::None = fixity {
|
|
break;
|
|
}
|
|
}
|
|
|
|
Ok(lhs)
|
|
}
|
|
|
|
fn should_continue_as_assoc_expr(&mut self, lhs: &Expr) -> bool {
|
|
match (self.expr_is_complete(lhs), AssocOp::from_token(&self.token)) {
|
|
// Semi-statement forms are odd:
|
|
// See https://github.com/rust-lang/rust/issues/29071
|
|
(true, None) => false,
|
|
(false, _) => true, // Continue parsing the expression.
|
|
// An exhaustive check is done in the following block, but these are checked first
|
|
// because they *are* ambiguous but also reasonable looking incorrect syntax, so we
|
|
// want to keep their span info to improve diagnostics in these cases in a later stage.
|
|
(true, Some(AssocOp::Multiply)) | // `{ 42 } *foo = bar;` or `{ 42 } * 3`
|
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(true, Some(AssocOp::Subtract)) | // `{ 42 } -5`
|
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(true, Some(AssocOp::Add)) | // `{ 42 } + 42` (unary plus)
|
|
(true, Some(AssocOp::LAnd)) | // `{ 42 } &&x` (#61475) or `{ 42 } && if x { 1 } else { 0 }`
|
|
(true, Some(AssocOp::LOr)) | // `{ 42 } || 42` ("logical or" or closure)
|
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(true, Some(AssocOp::BitOr)) // `{ 42 } | 42` or `{ 42 } |x| 42`
|
|
=> {
|
|
// These cases are ambiguous and can't be identified in the parser alone.
|
|
//
|
|
// Bitwise AND is left out because guessing intent is hard. We can make
|
|
// suggestions based on the assumption that double-refs are rarely intentional,
|
|
// and closures are distinct enough that they don't get mixed up with their
|
|
// return value.
|
|
let sp = self.sess.source_map().start_point(self.token.span);
|
|
self.sess.ambiguous_block_expr_parse.borrow_mut().insert(sp, lhs.span);
|
|
false
|
|
}
|
|
(true, Some(op)) if !op.can_continue_expr_unambiguously() => false,
|
|
(true, Some(_)) => {
|
|
self.error_found_expr_would_be_stmt(lhs);
|
|
true
|
|
}
|
|
}
|
|
}
|
|
|
|
/// We've found an expression that would be parsed as a statement,
|
|
/// but the next token implies this should be parsed as an expression.
|
|
/// For example: `if let Some(x) = x { x } else { 0 } / 2`.
|
|
fn error_found_expr_would_be_stmt(&self, lhs: &Expr) {
|
|
self.sess.emit_err(errors::FoundExprWouldBeStmt {
|
|
span: self.token.span,
|
|
token: self.token.clone(),
|
|
suggestion: ExprParenthesesNeeded::surrounding(lhs.span),
|
|
});
|
|
}
|
|
|
|
/// Possibly translate the current token to an associative operator.
|
|
/// The method does not advance the current token.
|
|
///
|
|
/// Also performs recovery for `and` / `or` which are mistaken for `&&` and `||` respectively.
|
|
fn check_assoc_op(&self) -> Option<Spanned<AssocOp>> {
|
|
let (op, span) = match (AssocOp::from_token(&self.token), self.token.ident()) {
|
|
// When parsing const expressions, stop parsing when encountering `>`.
|
|
(
|
|
Some(
|
|
AssocOp::ShiftRight
|
|
| AssocOp::Greater
|
|
| AssocOp::GreaterEqual
|
|
| AssocOp::AssignOp(token::BinOpToken::Shr),
|
|
),
|
|
_,
|
|
) if self.restrictions.contains(Restrictions::CONST_EXPR) => {
|
|
return None;
|
|
}
|
|
(Some(op), _) => (op, self.token.span),
|
|
(None, Some((Ident { name: sym::and, span }, false))) if self.may_recover() => {
|
|
self.sess.emit_err(errors::InvalidLogicalOperator {
|
|
span: self.token.span,
|
|
incorrect: "and".into(),
|
|
sub: errors::InvalidLogicalOperatorSub::Conjunction(self.token.span),
|
|
});
|
|
(AssocOp::LAnd, span)
|
|
}
|
|
(None, Some((Ident { name: sym::or, span }, false))) if self.may_recover() => {
|
|
self.sess.emit_err(errors::InvalidLogicalOperator {
|
|
span: self.token.span,
|
|
incorrect: "or".into(),
|
|
sub: errors::InvalidLogicalOperatorSub::Disjunction(self.token.span),
|
|
});
|
|
(AssocOp::LOr, span)
|
|
}
|
|
_ => return None,
|
|
};
|
|
Some(source_map::respan(span, op))
|
|
}
|
|
|
|
/// Checks if this expression is a successfully parsed statement.
|
|
fn expr_is_complete(&self, e: &Expr) -> bool {
|
|
self.restrictions.contains(Restrictions::STMT_EXPR)
|
|
&& !classify::expr_requires_semi_to_be_stmt(e)
|
|
}
|
|
|
|
/// Parses `x..y`, `x..=y`, and `x..`/`x..=`.
|
|
/// The other two variants are handled in `parse_prefix_range_expr` below.
|
|
fn parse_expr_range(
|
|
&mut self,
|
|
prec: usize,
|
|
lhs: P<Expr>,
|
|
op: AssocOp,
|
|
cur_op_span: Span,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let rhs = if self.is_at_start_of_range_notation_rhs() {
|
|
Some(self.parse_expr_assoc_with(prec + 1, LhsExpr::NotYetParsed)?)
|
|
} else {
|
|
None
|
|
};
|
|
let rhs_span = rhs.as_ref().map_or(cur_op_span, |x| x.span);
|
|
let span = self.mk_expr_sp(&lhs, lhs.span, rhs_span);
|
|
let limits =
|
|
if op == AssocOp::DotDot { RangeLimits::HalfOpen } else { RangeLimits::Closed };
|
|
let range = self.mk_range(Some(lhs), rhs, limits);
|
|
Ok(self.mk_expr(span, range))
|
|
}
|
|
|
|
fn is_at_start_of_range_notation_rhs(&self) -> bool {
|
|
if self.token.can_begin_expr() {
|
|
// Parse `for i in 1.. { }` as infinite loop, not as `for i in (1..{})`.
|
|
if self.token == token::OpenDelim(Delimiter::Brace) {
|
|
return !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
|
|
}
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
/// Parses prefix-forms of range notation: `..expr`, `..`, `..=expr`.
|
|
fn parse_expr_prefix_range(&mut self, attrs: Option<AttrWrapper>) -> PResult<'a, P<Expr>> {
|
|
// Check for deprecated `...` syntax.
|
|
if self.token == token::DotDotDot {
|
|
self.err_dotdotdot_syntax(self.token.span);
|
|
}
|
|
|
|
debug_assert!(
|
|
self.token.is_range_separator(),
|
|
"parse_prefix_range_expr: token {:?} is not DotDot/DotDotEq",
|
|
self.token
|
|
);
|
|
|
|
let limits = match self.token.kind {
|
|
token::DotDot => RangeLimits::HalfOpen,
|
|
_ => RangeLimits::Closed,
|
|
};
|
|
let op = AssocOp::from_token(&self.token);
|
|
// FIXME: `parse_prefix_range_expr` is called when the current
|
|
// token is `DotDot`, `DotDotDot`, or `DotDotEq`. If we haven't already
|
|
// parsed attributes, then trying to parse them here will always fail.
|
|
// We should figure out how we want attributes on range expressions to work.
|
|
let attrs = self.parse_or_use_outer_attributes(attrs)?;
|
|
self.collect_tokens_for_expr(attrs, |this, attrs| {
|
|
let lo = this.token.span;
|
|
this.bump();
|
|
let (span, opt_end) = if this.is_at_start_of_range_notation_rhs() {
|
|
// RHS must be parsed with more associativity than the dots.
|
|
this.parse_expr_assoc_with(op.unwrap().precedence() + 1, LhsExpr::NotYetParsed)
|
|
.map(|x| (lo.to(x.span), Some(x)))?
|
|
} else {
|
|
(lo, None)
|
|
};
|
|
let range = this.mk_range(None, opt_end, limits);
|
|
Ok(this.mk_expr_with_attrs(span, range, attrs))
|
|
})
|
|
}
|
|
|
|
/// Parses a prefix-unary-operator expr.
|
|
fn parse_expr_prefix(&mut self, attrs: Option<AttrWrapper>) -> PResult<'a, P<Expr>> {
|
|
let attrs = self.parse_or_use_outer_attributes(attrs)?;
|
|
let lo = self.token.span;
|
|
|
|
macro_rules! make_it {
|
|
($this:ident, $attrs:expr, |this, _| $body:expr) => {
|
|
$this.collect_tokens_for_expr($attrs, |$this, attrs| {
|
|
let (hi, ex) = $body?;
|
|
Ok($this.mk_expr_with_attrs(lo.to(hi), ex, attrs))
|
|
})
|
|
};
|
|
}
|
|
|
|
let this = self;
|
|
|
|
// Note: when adding new unary operators, don't forget to adjust TokenKind::can_begin_expr()
|
|
match this.token.uninterpolate().kind {
|
|
// `!expr`
|
|
token::Not => make_it!(this, attrs, |this, _| this.parse_expr_unary(lo, UnOp::Not)),
|
|
// `~expr`
|
|
token::Tilde => make_it!(this, attrs, |this, _| this.recover_tilde_expr(lo)),
|
|
// `-expr`
|
|
token::BinOp(token::Minus) => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_unary(lo, UnOp::Neg))
|
|
}
|
|
// `*expr`
|
|
token::BinOp(token::Star) => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_unary(lo, UnOp::Deref))
|
|
}
|
|
// `&expr` and `&&expr`
|
|
token::BinOp(token::And) | token::AndAnd => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_borrow(lo))
|
|
}
|
|
// `+lit`
|
|
token::BinOp(token::Plus) if this.look_ahead(1, |tok| tok.is_numeric_lit()) => {
|
|
let mut err = errors::LeadingPlusNotSupported {
|
|
span: lo,
|
|
remove_plus: None,
|
|
add_parentheses: None,
|
|
};
|
|
|
|
// a block on the LHS might have been intended to be an expression instead
|
|
if let Some(sp) = this.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
|
|
err.add_parentheses = Some(ExprParenthesesNeeded::surrounding(*sp));
|
|
} else {
|
|
err.remove_plus = Some(lo);
|
|
}
|
|
this.sess.emit_err(err);
|
|
|
|
this.bump();
|
|
this.parse_expr_prefix(None)
|
|
}
|
|
// Recover from `++x`:
|
|
token::BinOp(token::Plus)
|
|
if this.look_ahead(1, |t| *t == token::BinOp(token::Plus)) =>
|
|
{
|
|
let starts_stmt = this.prev_token == token::Semi
|
|
|| this.prev_token == token::CloseDelim(Delimiter::Brace);
|
|
let pre_span = this.token.span.to(this.look_ahead(1, |t| t.span));
|
|
// Eat both `+`s.
|
|
this.bump();
|
|
this.bump();
|
|
|
|
let operand_expr = this.parse_expr_dot_or_call(Default::default())?;
|
|
this.recover_from_prefix_increment(operand_expr, pre_span, starts_stmt)
|
|
}
|
|
token::Ident(..) if this.token.is_keyword(kw::Box) => {
|
|
make_it!(this, attrs, |this, _| this.parse_expr_box(lo))
|
|
}
|
|
token::Ident(..) if this.may_recover() && this.is_mistaken_not_ident_negation() => {
|
|
make_it!(this, attrs, |this, _| this.recover_not_expr(lo))
|
|
}
|
|
_ => {
|
|
return this.parse_expr_dot_or_call(Some(attrs));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn parse_expr_prefix_common(&mut self, lo: Span) -> PResult<'a, (Span, P<Expr>)> {
|
|
self.bump();
|
|
let expr = self.parse_expr_prefix(None);
|
|
let (span, expr) = self.interpolated_or_expr_span(expr)?;
|
|
Ok((lo.to(span), expr))
|
|
}
|
|
|
|
fn parse_expr_unary(&mut self, lo: Span, op: UnOp) -> PResult<'a, (Span, ExprKind)> {
|
|
let (span, expr) = self.parse_expr_prefix_common(lo)?;
|
|
Ok((span, self.mk_unary(op, expr)))
|
|
}
|
|
|
|
/// Recover on `~expr` in favor of `!expr`.
|
|
fn recover_tilde_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
self.sess.emit_err(errors::TildeAsUnaryOperator(lo));
|
|
|
|
self.parse_expr_unary(lo, UnOp::Not)
|
|
}
|
|
|
|
/// Parse `box expr` - this syntax has been removed, but we still parse this
|
|
/// for now to provide an automated way to fix usages of it
|
|
fn parse_expr_box(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
let (span, expr) = self.parse_expr_prefix_common(lo)?;
|
|
let code = self.sess.source_map().span_to_snippet(span.with_lo(lo.hi())).unwrap();
|
|
self.sess.emit_err(errors::BoxSyntaxRemoved { span, code: code.trim() });
|
|
// So typechecking works, parse `box <expr>` as `::std::boxed::Box::new(expr)`
|
|
let path = Path {
|
|
span,
|
|
segments: [
|
|
PathSegment::from_ident(Ident::with_dummy_span(PathRoot)),
|
|
PathSegment::from_ident(Ident::with_dummy_span(sym::std)),
|
|
PathSegment::from_ident(Ident::from_str("boxed")),
|
|
PathSegment::from_ident(Ident::from_str("Box")),
|
|
PathSegment::from_ident(Ident::with_dummy_span(sym::new)),
|
|
]
|
|
.into(),
|
|
tokens: None,
|
|
};
|
|
let path = self.mk_expr(span, ExprKind::Path(None, path));
|
|
Ok((span, self.mk_call(path, ThinVec::from([expr]))))
|
|
}
|
|
|
|
fn is_mistaken_not_ident_negation(&self) -> bool {
|
|
let token_cannot_continue_expr = |t: &Token| match t.uninterpolate().kind {
|
|
// These tokens can start an expression after `!`, but
|
|
// can't continue an expression after an ident
|
|
token::Ident(name, is_raw) => token::ident_can_begin_expr(name, t.span, is_raw),
|
|
token::Literal(..) | token::Pound => true,
|
|
_ => t.is_whole_expr(),
|
|
};
|
|
self.token.is_ident_named(sym::not) && self.look_ahead(1, token_cannot_continue_expr)
|
|
}
|
|
|
|
/// Recover on `not expr` in favor of `!expr`.
|
|
fn recover_not_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
let negated_token = self.look_ahead(1, |t| t.clone());
|
|
|
|
let sub_diag = if negated_token.is_numeric_lit() {
|
|
errors::NotAsNegationOperatorSub::SuggestNotBitwise
|
|
} else if negated_token.is_bool_lit() {
|
|
errors::NotAsNegationOperatorSub::SuggestNotLogical
|
|
} else {
|
|
errors::NotAsNegationOperatorSub::SuggestNotDefault
|
|
};
|
|
|
|
self.sess.emit_err(errors::NotAsNegationOperator {
|
|
negated: negated_token.span,
|
|
negated_desc: super::token_descr(&negated_token),
|
|
// Span the `not` plus trailing whitespace to avoid
|
|
// trailing whitespace after the `!` in our suggestion
|
|
sub: sub_diag(
|
|
self.sess.source_map().span_until_non_whitespace(lo.to(negated_token.span)),
|
|
),
|
|
});
|
|
|
|
self.parse_expr_unary(lo, UnOp::Not)
|
|
}
|
|
|
|
/// Returns the span of expr, if it was not interpolated or the span of the interpolated token.
|
|
fn interpolated_or_expr_span(
|
|
&self,
|
|
expr: PResult<'a, P<Expr>>,
|
|
) -> PResult<'a, (Span, P<Expr>)> {
|
|
expr.map(|e| {
|
|
(
|
|
match self.prev_token.kind {
|
|
TokenKind::Interpolated(..) => self.prev_token.span,
|
|
_ => e.span,
|
|
},
|
|
e,
|
|
)
|
|
})
|
|
}
|
|
|
|
fn parse_assoc_op_cast(
|
|
&mut self,
|
|
lhs: P<Expr>,
|
|
lhs_span: Span,
|
|
expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let mk_expr = |this: &mut Self, lhs: P<Expr>, rhs: P<Ty>| {
|
|
this.mk_expr(this.mk_expr_sp(&lhs, lhs_span, rhs.span), expr_kind(lhs, rhs))
|
|
};
|
|
|
|
// Save the state of the parser before parsing type normally, in case there is a
|
|
// LessThan comparison after this cast.
|
|
let parser_snapshot_before_type = self.clone();
|
|
let cast_expr = match self.parse_as_cast_ty() {
|
|
Ok(rhs) => mk_expr(self, lhs, rhs),
|
|
Err(type_err) => {
|
|
if !self.may_recover() {
|
|
return Err(type_err);
|
|
}
|
|
|
|
// Rewind to before attempting to parse the type with generics, to recover
|
|
// from situations like `x as usize < y` in which we first tried to parse
|
|
// `usize < y` as a type with generic arguments.
|
|
let parser_snapshot_after_type = mem::replace(self, parser_snapshot_before_type);
|
|
|
|
// Check for typo of `'a: loop { break 'a }` with a missing `'`.
|
|
match (&lhs.kind, &self.token.kind) {
|
|
(
|
|
// `foo: `
|
|
ExprKind::Path(None, ast::Path { segments, .. }),
|
|
token::Ident(kw::For | kw::Loop | kw::While, false),
|
|
) if segments.len() == 1 => {
|
|
let snapshot = self.create_snapshot_for_diagnostic();
|
|
let label = Label {
|
|
ident: Ident::from_str_and_span(
|
|
&format!("'{}", segments[0].ident),
|
|
segments[0].ident.span,
|
|
),
|
|
};
|
|
match self.parse_expr_labeled(label, false) {
|
|
Ok(expr) => {
|
|
type_err.cancel();
|
|
self.sess.emit_err(errors::MalformedLoopLabel {
|
|
span: label.ident.span,
|
|
correct_label: label.ident,
|
|
});
|
|
return Ok(expr);
|
|
}
|
|
Err(err) => {
|
|
err.cancel();
|
|
self.restore_snapshot(snapshot);
|
|
}
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
match self.parse_path(PathStyle::Expr) {
|
|
Ok(path) => {
|
|
let span_after_type = parser_snapshot_after_type.token.span;
|
|
let expr = mk_expr(
|
|
self,
|
|
lhs,
|
|
self.mk_ty(path.span, TyKind::Path(None, path.clone())),
|
|
);
|
|
|
|
let args_span = self.look_ahead(1, |t| t.span).to(span_after_type);
|
|
let suggestion = errors::ComparisonOrShiftInterpretedAsGenericSugg {
|
|
left: expr.span.shrink_to_lo(),
|
|
right: expr.span.shrink_to_hi(),
|
|
};
|
|
|
|
match self.token.kind {
|
|
token::Lt => {
|
|
self.sess.emit_err(errors::ComparisonInterpretedAsGeneric {
|
|
comparison: self.token.span,
|
|
r#type: path,
|
|
args: args_span,
|
|
suggestion,
|
|
})
|
|
}
|
|
token::BinOp(token::Shl) => {
|
|
self.sess.emit_err(errors::ShiftInterpretedAsGeneric {
|
|
shift: self.token.span,
|
|
r#type: path,
|
|
args: args_span,
|
|
suggestion,
|
|
})
|
|
}
|
|
_ => {
|
|
// We can end up here even without `<` being the next token, for
|
|
// example because `parse_ty_no_plus` returns `Err` on keywords,
|
|
// but `parse_path` returns `Ok` on them due to error recovery.
|
|
// Return original error and parser state.
|
|
*self = parser_snapshot_after_type;
|
|
return Err(type_err);
|
|
}
|
|
};
|
|
|
|
// Successfully parsed the type path leaving a `<` yet to parse.
|
|
type_err.cancel();
|
|
|
|
// Keep `x as usize` as an expression in AST and continue parsing.
|
|
expr
|
|
}
|
|
Err(path_err) => {
|
|
// Couldn't parse as a path, return original error and parser state.
|
|
path_err.cancel();
|
|
*self = parser_snapshot_after_type;
|
|
return Err(type_err);
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
self.parse_and_disallow_postfix_after_cast(cast_expr)
|
|
}
|
|
|
|
/// Parses a postfix operators such as `.`, `?`, or index (`[]`) after a cast,
|
|
/// then emits an error and returns the newly parsed tree.
|
|
/// The resulting parse tree for `&x as T[0]` has a precedence of `((&x) as T)[0]`.
|
|
fn parse_and_disallow_postfix_after_cast(
|
|
&mut self,
|
|
cast_expr: P<Expr>,
|
|
) -> PResult<'a, P<Expr>> {
|
|
if let ExprKind::Type(_, _) = cast_expr.kind {
|
|
panic!("ExprKind::Type must not be parsed");
|
|
}
|
|
|
|
let span = cast_expr.span;
|
|
|
|
let with_postfix = self.parse_expr_dot_or_call_with_(cast_expr, span)?;
|
|
|
|
// Check if an illegal postfix operator has been added after the cast.
|
|
// If the resulting expression is not a cast, it is an illegal postfix operator.
|
|
if !matches!(with_postfix.kind, ExprKind::Cast(_, _)) {
|
|
let msg = format!(
|
|
"cast cannot be followed by {}",
|
|
match with_postfix.kind {
|
|
ExprKind::Index(_, _) => "indexing",
|
|
ExprKind::Try(_) => "`?`",
|
|
ExprKind::Field(_, _) => "a field access",
|
|
ExprKind::MethodCall(_) => "a method call",
|
|
ExprKind::Call(_, _) => "a function call",
|
|
ExprKind::Await(_, _) => "`.await`",
|
|
ExprKind::Err => return Ok(with_postfix),
|
|
_ => unreachable!("parse_dot_or_call_expr_with_ shouldn't produce this"),
|
|
}
|
|
);
|
|
let mut err = self.struct_span_err(span, &msg);
|
|
|
|
let suggest_parens = |err: &mut Diagnostic| {
|
|
let suggestions = vec![
|
|
(span.shrink_to_lo(), "(".to_string()),
|
|
(span.shrink_to_hi(), ")".to_string()),
|
|
];
|
|
err.multipart_suggestion(
|
|
"try surrounding the expression in parentheses",
|
|
suggestions,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
};
|
|
|
|
suggest_parens(&mut err);
|
|
|
|
err.emit();
|
|
};
|
|
Ok(with_postfix)
|
|
}
|
|
|
|
/// Parse `& mut? <expr>` or `& raw [ const | mut ] <expr>`.
|
|
fn parse_expr_borrow(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
|
|
self.expect_and()?;
|
|
let has_lifetime = self.token.is_lifetime() && self.look_ahead(1, |t| t != &token::Colon);
|
|
let lifetime = has_lifetime.then(|| self.expect_lifetime()); // For recovery, see below.
|
|
let (borrow_kind, mutbl) = self.parse_borrow_modifiers(lo);
|
|
let expr = if self.token.is_range_separator() {
|
|
self.parse_expr_prefix_range(None)
|
|
} else {
|
|
self.parse_expr_prefix(None)
|
|
};
|
|
let (hi, expr) = self.interpolated_or_expr_span(expr)?;
|
|
let span = lo.to(hi);
|
|
if let Some(lt) = lifetime {
|
|
self.error_remove_borrow_lifetime(span, lt.ident.span);
|
|
}
|
|
Ok((span, ExprKind::AddrOf(borrow_kind, mutbl, expr)))
|
|
}
|
|
|
|
fn error_remove_borrow_lifetime(&self, span: Span, lt_span: Span) {
|
|
self.sess.emit_err(errors::LifetimeInBorrowExpression { span, lifetime_span: lt_span });
|
|
}
|
|
|
|
/// Parse `mut?` or `raw [ const | mut ]`.
|
|
fn parse_borrow_modifiers(&mut self, lo: Span) -> (ast::BorrowKind, ast::Mutability) {
|
|
if self.check_keyword(kw::Raw) && self.look_ahead(1, Token::is_mutability) {
|
|
// `raw [ const | mut ]`.
|
|
let found_raw = self.eat_keyword(kw::Raw);
|
|
assert!(found_raw);
|
|
let mutability = self.parse_const_or_mut().unwrap();
|
|
self.sess.gated_spans.gate(sym::raw_ref_op, lo.to(self.prev_token.span));
|
|
(ast::BorrowKind::Raw, mutability)
|
|
} else {
|
|
// `mut?`
|
|
(ast::BorrowKind::Ref, self.parse_mutability())
|
|
}
|
|
}
|
|
|
|
/// Parses `a.b` or `a(13)` or `a[4]` or just `a`.
|
|
fn parse_expr_dot_or_call(&mut self, attrs: Option<AttrWrapper>) -> PResult<'a, P<Expr>> {
|
|
let attrs = self.parse_or_use_outer_attributes(attrs)?;
|
|
self.collect_tokens_for_expr(attrs, |this, attrs| {
|
|
let base = this.parse_expr_bottom();
|
|
let (span, base) = this.interpolated_or_expr_span(base)?;
|
|
this.parse_expr_dot_or_call_with(base, span, attrs)
|
|
})
|
|
}
|
|
|
|
pub(super) fn parse_expr_dot_or_call_with(
|
|
&mut self,
|
|
e0: P<Expr>,
|
|
lo: Span,
|
|
mut attrs: ast::AttrVec,
|
|
) -> PResult<'a, P<Expr>> {
|
|
// Stitch the list of outer attributes onto the return value.
|
|
// A little bit ugly, but the best way given the current code
|
|
// structure
|
|
let res = self.parse_expr_dot_or_call_with_(e0, lo);
|
|
if attrs.is_empty() {
|
|
res
|
|
} else {
|
|
res.map(|expr| {
|
|
expr.map(|mut expr| {
|
|
attrs.extend(expr.attrs);
|
|
expr.attrs = attrs;
|
|
expr
|
|
})
|
|
})
|
|
}
|
|
}
|
|
|
|
fn parse_expr_dot_or_call_with_(&mut self, mut e: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
loop {
|
|
let has_question = if self.prev_token.kind == TokenKind::Ident(kw::Return, false) {
|
|
// we are using noexpect here because we don't expect a `?` directly after a `return`
|
|
// which could be suggested otherwise
|
|
self.eat_noexpect(&token::Question)
|
|
} else {
|
|
self.eat(&token::Question)
|
|
};
|
|
if has_question {
|
|
// `expr?`
|
|
e = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Try(e));
|
|
continue;
|
|
}
|
|
let has_dot = if self.prev_token.kind == TokenKind::Ident(kw::Return, false) {
|
|
// we are using noexpect here because we don't expect a `.` directly after a `return`
|
|
// which could be suggested otherwise
|
|
self.eat_noexpect(&token::Dot)
|
|
} else {
|
|
self.eat(&token::Dot)
|
|
};
|
|
if has_dot {
|
|
// expr.f
|
|
e = self.parse_dot_suffix_expr(lo, e)?;
|
|
continue;
|
|
}
|
|
if self.expr_is_complete(&e) {
|
|
return Ok(e);
|
|
}
|
|
e = match self.token.kind {
|
|
token::OpenDelim(Delimiter::Parenthesis) => self.parse_expr_fn_call(lo, e),
|
|
token::OpenDelim(Delimiter::Bracket) => self.parse_expr_index(lo, e)?,
|
|
_ => return Ok(e),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn parse_dot_suffix_expr(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
|
|
match self.token.uninterpolate().kind {
|
|
token::Ident(..) => self.parse_dot_suffix(base, lo),
|
|
token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) => {
|
|
Ok(self.parse_expr_tuple_field_access(lo, base, symbol, suffix, None))
|
|
}
|
|
token::Literal(token::Lit { kind: token::Float, symbol, suffix }) => {
|
|
Ok(self.parse_expr_tuple_field_access_float(lo, base, symbol, suffix))
|
|
}
|
|
_ => {
|
|
self.error_unexpected_after_dot();
|
|
Ok(base)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn error_unexpected_after_dot(&self) {
|
|
// FIXME Could factor this out into non_fatal_unexpected or something.
|
|
let actual = pprust::token_to_string(&self.token);
|
|
self.sess.emit_err(errors::UnexpectedTokenAfterDot { span: self.token.span, actual });
|
|
}
|
|
|
|
// We need an identifier or integer, but the next token is a float.
|
|
// Break the float into components to extract the identifier or integer.
|
|
// FIXME: With current `TokenCursor` it's hard to break tokens into more than 2
|
|
// parts unless those parts are processed immediately. `TokenCursor` should either
|
|
// support pushing "future tokens" (would be also helpful to `break_and_eat`), or
|
|
// we should break everything including floats into more basic proc-macro style
|
|
// tokens in the lexer (probably preferable).
|
|
fn parse_expr_tuple_field_access_float(
|
|
&mut self,
|
|
lo: Span,
|
|
base: P<Expr>,
|
|
float: Symbol,
|
|
suffix: Option<Symbol>,
|
|
) -> P<Expr> {
|
|
#[derive(Debug)]
|
|
enum FloatComponent {
|
|
IdentLike(String),
|
|
Punct(char),
|
|
}
|
|
use FloatComponent::*;
|
|
|
|
let float_str = float.as_str();
|
|
let mut components = Vec::new();
|
|
let mut ident_like = String::new();
|
|
for c in float_str.chars() {
|
|
if c == '_' || c.is_ascii_alphanumeric() {
|
|
ident_like.push(c);
|
|
} else if matches!(c, '.' | '+' | '-') {
|
|
if !ident_like.is_empty() {
|
|
components.push(IdentLike(mem::take(&mut ident_like)));
|
|
}
|
|
components.push(Punct(c));
|
|
} else {
|
|
panic!("unexpected character in a float token: {:?}", c)
|
|
}
|
|
}
|
|
if !ident_like.is_empty() {
|
|
components.push(IdentLike(ident_like));
|
|
}
|
|
|
|
// With proc macros the span can refer to anything, the source may be too short,
|
|
// or too long, or non-ASCII. It only makes sense to break our span into components
|
|
// if its underlying text is identical to our float literal.
|
|
let span = self.token.span;
|
|
let can_take_span_apart =
|
|
|| self.span_to_snippet(span).as_deref() == Ok(float_str).as_deref();
|
|
|
|
match &*components {
|
|
// 1e2
|
|
[IdentLike(i)] => {
|
|
self.parse_expr_tuple_field_access(lo, base, Symbol::intern(&i), suffix, None)
|
|
}
|
|
// 1.
|
|
[IdentLike(i), Punct('.')] => {
|
|
let (ident_span, dot_span) = if can_take_span_apart() {
|
|
let (span, ident_len) = (span.data(), BytePos::from_usize(i.len()));
|
|
let ident_span = span.with_hi(span.lo + ident_len);
|
|
let dot_span = span.with_lo(span.lo + ident_len);
|
|
(ident_span, dot_span)
|
|
} else {
|
|
(span, span)
|
|
};
|
|
assert!(suffix.is_none());
|
|
let symbol = Symbol::intern(&i);
|
|
self.token = Token::new(token::Ident(symbol, false), ident_span);
|
|
let next_token = (Token::new(token::Dot, dot_span), self.token_spacing);
|
|
self.parse_expr_tuple_field_access(lo, base, symbol, None, Some(next_token))
|
|
}
|
|
// 1.2 | 1.2e3
|
|
[IdentLike(i1), Punct('.'), IdentLike(i2)] => {
|
|
let (ident1_span, dot_span, ident2_span) = if can_take_span_apart() {
|
|
let (span, ident1_len) = (span.data(), BytePos::from_usize(i1.len()));
|
|
let ident1_span = span.with_hi(span.lo + ident1_len);
|
|
let dot_span = span
|
|
.with_lo(span.lo + ident1_len)
|
|
.with_hi(span.lo + ident1_len + BytePos(1));
|
|
let ident2_span = self.token.span.with_lo(span.lo + ident1_len + BytePos(1));
|
|
(ident1_span, dot_span, ident2_span)
|
|
} else {
|
|
(span, span, span)
|
|
};
|
|
let symbol1 = Symbol::intern(&i1);
|
|
self.token = Token::new(token::Ident(symbol1, false), ident1_span);
|
|
// This needs to be `Spacing::Alone` to prevent regressions.
|
|
// See issue #76399 and PR #76285 for more details
|
|
let next_token1 = (Token::new(token::Dot, dot_span), Spacing::Alone);
|
|
let base1 =
|
|
self.parse_expr_tuple_field_access(lo, base, symbol1, None, Some(next_token1));
|
|
let symbol2 = Symbol::intern(&i2);
|
|
let next_token2 = Token::new(token::Ident(symbol2, false), ident2_span);
|
|
self.bump_with((next_token2, self.token_spacing)); // `.`
|
|
self.parse_expr_tuple_field_access(lo, base1, symbol2, suffix, None)
|
|
}
|
|
// 1e+ | 1e- (recovered)
|
|
[IdentLike(_), Punct('+' | '-')] |
|
|
// 1e+2 | 1e-2
|
|
[IdentLike(_), Punct('+' | '-'), IdentLike(_)] |
|
|
// 1.2e+ | 1.2e-
|
|
[IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-')] |
|
|
// 1.2e+3 | 1.2e-3
|
|
[IdentLike(_), Punct('.'), IdentLike(_), Punct('+' | '-'), IdentLike(_)] => {
|
|
// See the FIXME about `TokenCursor` above.
|
|
self.error_unexpected_after_dot();
|
|
base
|
|
}
|
|
_ => panic!("unexpected components in a float token: {:?}", components),
|
|
}
|
|
}
|
|
|
|
fn parse_expr_tuple_field_access(
|
|
&mut self,
|
|
lo: Span,
|
|
base: P<Expr>,
|
|
field: Symbol,
|
|
suffix: Option<Symbol>,
|
|
next_token: Option<(Token, Spacing)>,
|
|
) -> P<Expr> {
|
|
match next_token {
|
|
Some(next_token) => self.bump_with(next_token),
|
|
None => self.bump(),
|
|
}
|
|
let span = self.prev_token.span;
|
|
let field = ExprKind::Field(base, Ident::new(field, span));
|
|
if let Some(suffix) = suffix {
|
|
self.expect_no_tuple_index_suffix(span, suffix);
|
|
}
|
|
self.mk_expr(lo.to(span), field)
|
|
}
|
|
|
|
/// Parse a function call expression, `expr(...)`.
|
|
fn parse_expr_fn_call(&mut self, lo: Span, fun: P<Expr>) -> P<Expr> {
|
|
let snapshot = if self.token.kind == token::OpenDelim(Delimiter::Parenthesis) {
|
|
Some((self.create_snapshot_for_diagnostic(), fun.kind.clone()))
|
|
} else {
|
|
None
|
|
};
|
|
let open_paren = self.token.span;
|
|
|
|
let mut seq = self
|
|
.parse_expr_paren_seq()
|
|
.map(|args| self.mk_expr(lo.to(self.prev_token.span), self.mk_call(fun, args)));
|
|
if let Some(expr) =
|
|
self.maybe_recover_struct_lit_bad_delims(lo, open_paren, &mut seq, snapshot)
|
|
{
|
|
return expr;
|
|
}
|
|
self.recover_seq_parse_error(Delimiter::Parenthesis, lo, seq)
|
|
}
|
|
|
|
/// If we encounter a parser state that looks like the user has written a `struct` literal with
|
|
/// parentheses instead of braces, recover the parser state and provide suggestions.
|
|
#[instrument(skip(self, seq, snapshot), level = "trace")]
|
|
fn maybe_recover_struct_lit_bad_delims(
|
|
&mut self,
|
|
lo: Span,
|
|
open_paren: Span,
|
|
seq: &mut PResult<'a, P<Expr>>,
|
|
snapshot: Option<(SnapshotParser<'a>, ExprKind)>,
|
|
) -> Option<P<Expr>> {
|
|
if !self.may_recover() {
|
|
return None;
|
|
}
|
|
match (seq.as_mut(), snapshot) {
|
|
(Err(err), Some((mut snapshot, ExprKind::Path(None, path)))) => {
|
|
snapshot.bump(); // `(`
|
|
match snapshot.parse_struct_fields(path.clone(), false, Delimiter::Parenthesis) {
|
|
Ok((fields, ..))
|
|
if snapshot.eat(&token::CloseDelim(Delimiter::Parenthesis)) =>
|
|
{
|
|
// We are certain we have `Enum::Foo(a: 3, b: 4)`, suggest
|
|
// `Enum::Foo { a: 3, b: 4 }` or `Enum::Foo(3, 4)`.
|
|
self.restore_snapshot(snapshot);
|
|
let close_paren = self.prev_token.span;
|
|
let span = lo.to(close_paren);
|
|
if !fields.is_empty() &&
|
|
// `token.kind` should not be compared here.
|
|
// This is because the `snapshot.token.kind` is treated as the same as
|
|
// that of the open delim in `TokenTreesReader::parse_token_tree`, even if they are different.
|
|
self.span_to_snippet(close_paren).map_or(false, |snippet| snippet == ")")
|
|
{
|
|
let mut replacement_err = errors::ParenthesesWithStructFields {
|
|
span,
|
|
r#type: path,
|
|
braces_for_struct: errors::BracesForStructLiteral {
|
|
first: open_paren,
|
|
second: close_paren,
|
|
},
|
|
no_fields_for_fn: errors::NoFieldsForFnCall {
|
|
fields: fields
|
|
.into_iter()
|
|
.map(|field| field.span.until(field.expr.span))
|
|
.collect(),
|
|
},
|
|
}
|
|
.into_diagnostic(&self.sess.span_diagnostic);
|
|
replacement_err.emit();
|
|
|
|
let old_err = mem::replace(err, replacement_err);
|
|
old_err.cancel();
|
|
} else {
|
|
err.emit();
|
|
}
|
|
return Some(self.mk_expr_err(span));
|
|
}
|
|
Ok(_) => {}
|
|
Err(err) => err.cancel(),
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
None
|
|
}
|
|
|
|
/// Parse an indexing expression `expr[...]`.
|
|
fn parse_expr_index(&mut self, lo: Span, base: P<Expr>) -> PResult<'a, P<Expr>> {
|
|
let prev_span = self.prev_token.span;
|
|
let open_delim_span = self.token.span;
|
|
self.bump(); // `[`
|
|
let index = self.parse_expr()?;
|
|
self.suggest_missing_semicolon_before_array(prev_span, open_delim_span)?;
|
|
self.expect(&token::CloseDelim(Delimiter::Bracket))?;
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_index(base, index)))
|
|
}
|
|
|
|
/// Assuming we have just parsed `.`, continue parsing into an expression.
|
|
fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
if self.token.uninterpolated_span().rust_2018() && self.eat_keyword(kw::Await) {
|
|
return Ok(self.mk_await_expr(self_arg, lo));
|
|
}
|
|
|
|
let fn_span_lo = self.token.span;
|
|
let mut seg = self.parse_path_segment(PathStyle::Expr, None)?;
|
|
self.check_trailing_angle_brackets(&seg, &[&token::OpenDelim(Delimiter::Parenthesis)]);
|
|
self.check_turbofish_missing_angle_brackets(&mut seg);
|
|
|
|
if self.check(&token::OpenDelim(Delimiter::Parenthesis)) {
|
|
// Method call `expr.f()`
|
|
let args = self.parse_expr_paren_seq()?;
|
|
let fn_span = fn_span_lo.to(self.prev_token.span);
|
|
let span = lo.to(self.prev_token.span);
|
|
Ok(self.mk_expr(
|
|
span,
|
|
ExprKind::MethodCall(Box::new(ast::MethodCall {
|
|
seg,
|
|
receiver: self_arg,
|
|
args,
|
|
span: fn_span,
|
|
})),
|
|
))
|
|
} else {
|
|
// Field access `expr.f`
|
|
if let Some(args) = seg.args {
|
|
self.sess.emit_err(errors::FieldExpressionWithGeneric(args.span()));
|
|
}
|
|
|
|
let span = lo.to(self.prev_token.span);
|
|
Ok(self.mk_expr(span, ExprKind::Field(self_arg, seg.ident)))
|
|
}
|
|
}
|
|
|
|
/// At the bottom (top?) of the precedence hierarchy,
|
|
/// Parses things like parenthesized exprs, macros, `return`, etc.
|
|
///
|
|
/// N.B., this does not parse outer attributes, and is private because it only works
|
|
/// correctly if called from `parse_dot_or_call_expr()`.
|
|
fn parse_expr_bottom(&mut self) -> PResult<'a, P<Expr>> {
|
|
maybe_recover_from_interpolated_ty_qpath!(self, true);
|
|
maybe_whole_expr!(self);
|
|
|
|
// Outer attributes are already parsed and will be
|
|
// added to the return value after the fact.
|
|
|
|
// Note: when adding new syntax here, don't forget to adjust `TokenKind::can_begin_expr()`.
|
|
let lo = self.token.span;
|
|
if let token::Literal(_) = self.token.kind {
|
|
// This match arm is a special-case of the `_` match arm below and
|
|
// could be removed without changing functionality, but it's faster
|
|
// to have it here, especially for programs with large constants.
|
|
self.parse_expr_lit()
|
|
} else if self.check(&token::OpenDelim(Delimiter::Parenthesis)) {
|
|
self.parse_expr_tuple_parens()
|
|
} else if self.check(&token::OpenDelim(Delimiter::Brace)) {
|
|
self.parse_expr_block(None, lo, BlockCheckMode::Default)
|
|
} else if self.check(&token::BinOp(token::Or)) || self.check(&token::OrOr) {
|
|
self.parse_expr_closure().map_err(|mut err| {
|
|
// If the input is something like `if a { 1 } else { 2 } | if a { 3 } else { 4 }`
|
|
// then suggest parens around the lhs.
|
|
if let Some(sp) = self.sess.ambiguous_block_expr_parse.borrow().get(&lo) {
|
|
err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
|
|
}
|
|
err
|
|
})
|
|
} else if self.check(&token::OpenDelim(Delimiter::Bracket)) {
|
|
self.parse_expr_array_or_repeat(Delimiter::Bracket)
|
|
} else if self.check_path() {
|
|
self.parse_expr_path_start()
|
|
} else if self.check_keyword(kw::Move)
|
|
|| self.check_keyword(kw::Static)
|
|
|| self.check_const_closure()
|
|
{
|
|
self.parse_expr_closure()
|
|
} else if self.eat_keyword(kw::If) {
|
|
self.parse_expr_if()
|
|
} else if self.check_keyword(kw::For) {
|
|
if self.choose_generics_over_qpath(1) {
|
|
self.parse_expr_closure()
|
|
} else {
|
|
assert!(self.eat_keyword(kw::For));
|
|
self.parse_expr_for(None, self.prev_token.span)
|
|
}
|
|
} else if self.eat_keyword(kw::While) {
|
|
self.parse_expr_while(None, self.prev_token.span)
|
|
} else if let Some(label) = self.eat_label() {
|
|
self.parse_expr_labeled(label, true)
|
|
} else if self.eat_keyword(kw::Loop) {
|
|
let sp = self.prev_token.span;
|
|
self.parse_expr_loop(None, self.prev_token.span).map_err(|mut err| {
|
|
err.span_label(sp, "while parsing this `loop` expression");
|
|
err
|
|
})
|
|
} else if self.eat_keyword(kw::Match) {
|
|
let match_sp = self.prev_token.span;
|
|
self.parse_expr_match().map_err(|mut err| {
|
|
err.span_label(match_sp, "while parsing this `match` expression");
|
|
err
|
|
})
|
|
} else if self.eat_keyword(kw::Unsafe) {
|
|
let sp = self.prev_token.span;
|
|
self.parse_expr_block(None, lo, BlockCheckMode::Unsafe(ast::UserProvided)).map_err(
|
|
|mut err| {
|
|
err.span_label(sp, "while parsing this `unsafe` expression");
|
|
err
|
|
},
|
|
)
|
|
} else if self.check_inline_const(0) {
|
|
self.parse_const_block(lo.to(self.token.span), false)
|
|
} else if self.may_recover() && self.is_do_catch_block() {
|
|
self.recover_do_catch()
|
|
} else if self.is_try_block() {
|
|
self.expect_keyword(kw::Try)?;
|
|
self.parse_try_block(lo)
|
|
} else if self.eat_keyword(kw::Return) {
|
|
self.parse_expr_return()
|
|
} else if self.eat_keyword(kw::Continue) {
|
|
self.parse_expr_continue(lo)
|
|
} else if self.eat_keyword(kw::Break) {
|
|
self.parse_expr_break()
|
|
} else if self.eat_keyword(kw::Yield) {
|
|
self.parse_expr_yield()
|
|
} else if self.is_do_yeet() {
|
|
self.parse_expr_yeet()
|
|
} else if self.check_keyword(kw::Let) {
|
|
self.parse_expr_let()
|
|
} else if self.eat_keyword(kw::Underscore) {
|
|
Ok(self.mk_expr(self.prev_token.span, ExprKind::Underscore))
|
|
} else if self.token.uninterpolated_span().rust_2018() {
|
|
// `Span::rust_2018()` is somewhat expensive; don't get it repeatedly.
|
|
if self.check_keyword(kw::Async) {
|
|
if self.is_async_block() {
|
|
// Check for `async {` and `async move {`.
|
|
self.parse_async_block()
|
|
} else {
|
|
self.parse_expr_closure()
|
|
}
|
|
} else if self.eat_keyword(kw::Await) {
|
|
self.recover_incorrect_await_syntax(lo, self.prev_token.span)
|
|
} else {
|
|
self.parse_expr_lit()
|
|
}
|
|
} else {
|
|
self.parse_expr_lit()
|
|
}
|
|
}
|
|
|
|
fn parse_expr_lit(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
match self.parse_opt_token_lit() {
|
|
Some((token_lit, _)) => {
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Lit(token_lit));
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
None => self.try_macro_suggestion(),
|
|
}
|
|
}
|
|
|
|
fn parse_expr_tuple_parens(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
self.expect(&token::OpenDelim(Delimiter::Parenthesis))?;
|
|
let (es, trailing_comma) = match self.parse_seq_to_end(
|
|
&token::CloseDelim(Delimiter::Parenthesis),
|
|
SeqSep::trailing_allowed(token::Comma),
|
|
|p| p.parse_expr_catch_underscore(),
|
|
) {
|
|
Ok(x) => x,
|
|
Err(err) => {
|
|
return Ok(self.recover_seq_parse_error(Delimiter::Parenthesis, lo, Err(err)));
|
|
}
|
|
};
|
|
let kind = if es.len() == 1 && !trailing_comma {
|
|
// `(e)` is parenthesized `e`.
|
|
ExprKind::Paren(es.into_iter().next().unwrap())
|
|
} else {
|
|
// `(e,)` is a tuple with only one field, `e`.
|
|
ExprKind::Tup(es)
|
|
};
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
fn parse_expr_array_or_repeat(&mut self, close_delim: Delimiter) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
self.bump(); // `[` or other open delim
|
|
|
|
let close = &token::CloseDelim(close_delim);
|
|
let kind = if self.eat(close) {
|
|
// Empty vector
|
|
ExprKind::Array(ThinVec::new())
|
|
} else {
|
|
// Non-empty vector
|
|
let first_expr = self.parse_expr()?;
|
|
if self.eat(&token::Semi) {
|
|
// Repeating array syntax: `[ 0; 512 ]`
|
|
let count = self.parse_expr_anon_const()?;
|
|
self.expect(close)?;
|
|
ExprKind::Repeat(first_expr, count)
|
|
} else if self.eat(&token::Comma) {
|
|
// Vector with two or more elements.
|
|
let sep = SeqSep::trailing_allowed(token::Comma);
|
|
let (mut exprs, _) = self.parse_seq_to_end(close, sep, |p| p.parse_expr())?;
|
|
exprs.insert(0, first_expr);
|
|
ExprKind::Array(exprs)
|
|
} else {
|
|
// Vector with one element
|
|
self.expect(close)?;
|
|
ExprKind::Array(thin_vec![first_expr])
|
|
}
|
|
};
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
fn parse_expr_path_start(&mut self) -> PResult<'a, P<Expr>> {
|
|
let (qself, path) = if self.eat_lt() {
|
|
let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
|
|
(Some(qself), path)
|
|
} else {
|
|
(None, self.parse_path(PathStyle::Expr)?)
|
|
};
|
|
|
|
// `!`, as an operator, is prefix, so we know this isn't that.
|
|
let (span, kind) = if self.eat(&token::Not) {
|
|
// MACRO INVOCATION expression
|
|
if qself.is_some() {
|
|
self.sess.emit_err(errors::MacroInvocationWithQualifiedPath(path.span));
|
|
}
|
|
let lo = path.span;
|
|
let mac = P(MacCall {
|
|
path,
|
|
args: self.parse_delim_args()?,
|
|
});
|
|
(lo.to(self.prev_token.span), ExprKind::MacCall(mac))
|
|
} else if self.check(&token::OpenDelim(Delimiter::Brace))
|
|
&& let Some(expr) = self.maybe_parse_struct_expr(&qself, &path)
|
|
{
|
|
if qself.is_some() {
|
|
self.sess.gated_spans.gate(sym::more_qualified_paths, path.span);
|
|
}
|
|
return expr;
|
|
} else {
|
|
(path.span, ExprKind::Path(qself, path))
|
|
};
|
|
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `'label: $expr`. The label is already parsed.
|
|
pub(super) fn parse_expr_labeled(
|
|
&mut self,
|
|
label_: Label,
|
|
mut consume_colon: bool,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let lo = label_.ident.span;
|
|
let label = Some(label_);
|
|
let ate_colon = self.eat(&token::Colon);
|
|
let expr = if self.eat_keyword(kw::While) {
|
|
self.parse_expr_while(label, lo)
|
|
} else if self.eat_keyword(kw::For) {
|
|
self.parse_expr_for(label, lo)
|
|
} else if self.eat_keyword(kw::Loop) {
|
|
self.parse_expr_loop(label, lo)
|
|
} else if self.check_noexpect(&token::OpenDelim(Delimiter::Brace))
|
|
|| self.token.is_whole_block()
|
|
{
|
|
self.parse_expr_block(label, lo, BlockCheckMode::Default)
|
|
} else if !ate_colon
|
|
&& self.may_recover()
|
|
&& (matches!(self.token.kind, token::CloseDelim(_) | token::Comma)
|
|
|| self.token.is_op())
|
|
{
|
|
let (lit, _) =
|
|
self.recover_unclosed_char(label_.ident, Parser::mk_token_lit_char, |self_| {
|
|
self_.sess.create_err(errors::UnexpectedTokenAfterLabel {
|
|
span: self_.token.span,
|
|
remove_label: None,
|
|
enclose_in_block: None,
|
|
})
|
|
});
|
|
consume_colon = false;
|
|
Ok(self.mk_expr(lo, ExprKind::Lit(lit)))
|
|
} else if !ate_colon
|
|
&& (self.check_noexpect(&TokenKind::Comma) || self.check_noexpect(&TokenKind::Gt))
|
|
{
|
|
// We're probably inside of a `Path<'a>` that needs a turbofish
|
|
self.sess.emit_err(errors::UnexpectedTokenAfterLabel {
|
|
span: self.token.span,
|
|
remove_label: None,
|
|
enclose_in_block: None,
|
|
});
|
|
consume_colon = false;
|
|
Ok(self.mk_expr_err(lo))
|
|
} else {
|
|
let mut err = errors::UnexpectedTokenAfterLabel {
|
|
span: self.token.span,
|
|
remove_label: None,
|
|
enclose_in_block: None,
|
|
};
|
|
|
|
// Continue as an expression in an effort to recover on `'label: non_block_expr`.
|
|
let expr = self.parse_expr().map(|expr| {
|
|
let span = expr.span;
|
|
|
|
let found_labeled_breaks = {
|
|
struct FindLabeledBreaksVisitor(bool);
|
|
|
|
impl<'ast> Visitor<'ast> for FindLabeledBreaksVisitor {
|
|
fn visit_expr_post(&mut self, ex: &'ast Expr) {
|
|
if let ExprKind::Break(Some(_label), _) = ex.kind {
|
|
self.0 = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
let mut vis = FindLabeledBreaksVisitor(false);
|
|
vis.visit_expr(&expr);
|
|
vis.0
|
|
};
|
|
|
|
// Suggestion involves adding a labeled block.
|
|
//
|
|
// If there are no breaks that may use this label, suggest removing the label and
|
|
// recover to the unmodified expression.
|
|
if !found_labeled_breaks {
|
|
err.remove_label = Some(lo.until(span));
|
|
|
|
return expr;
|
|
}
|
|
|
|
err.enclose_in_block = Some(errors::UnexpectedTokenAfterLabelSugg {
|
|
left: span.shrink_to_lo(),
|
|
right: span.shrink_to_hi(),
|
|
});
|
|
|
|
// Replace `'label: non_block_expr` with `'label: {non_block_expr}` in order to suppress future errors about `break 'label`.
|
|
let stmt = self.mk_stmt(span, StmtKind::Expr(expr));
|
|
let blk = self.mk_block(thin_vec![stmt], BlockCheckMode::Default, span);
|
|
self.mk_expr(span, ExprKind::Block(blk, label))
|
|
});
|
|
|
|
self.sess.emit_err(err);
|
|
expr
|
|
}?;
|
|
|
|
if !ate_colon && consume_colon {
|
|
self.sess.emit_err(errors::RequireColonAfterLabeledExpression {
|
|
span: expr.span,
|
|
label: lo,
|
|
label_end: lo.shrink_to_hi(),
|
|
});
|
|
}
|
|
|
|
Ok(expr)
|
|
}
|
|
|
|
/// Emit an error when a char is parsed as a lifetime because of a missing quote.
|
|
pub(super) fn recover_unclosed_char<L>(
|
|
&self,
|
|
lifetime: Ident,
|
|
mk_lit_char: impl FnOnce(Symbol, Span) -> L,
|
|
err: impl FnOnce(&Self) -> DiagnosticBuilder<'a, ErrorGuaranteed>,
|
|
) -> L {
|
|
if let Some(mut diag) =
|
|
self.sess.span_diagnostic.steal_diagnostic(lifetime.span, StashKey::LifetimeIsChar)
|
|
{
|
|
diag.span_suggestion_verbose(
|
|
lifetime.span.shrink_to_hi(),
|
|
"add `'` to close the char literal",
|
|
"'",
|
|
Applicability::MaybeIncorrect,
|
|
)
|
|
.emit();
|
|
} else {
|
|
err(self)
|
|
.span_suggestion_verbose(
|
|
lifetime.span.shrink_to_hi(),
|
|
"add `'` to close the char literal",
|
|
"'",
|
|
Applicability::MaybeIncorrect,
|
|
)
|
|
.emit();
|
|
}
|
|
let name = lifetime.without_first_quote().name;
|
|
mk_lit_char(name, lifetime.span)
|
|
}
|
|
|
|
/// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.
|
|
fn recover_do_catch(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
|
|
self.bump(); // `do`
|
|
self.bump(); // `catch`
|
|
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.emit_err(errors::DoCatchSyntaxRemoved { span });
|
|
|
|
self.parse_try_block(lo)
|
|
}
|
|
|
|
/// Parse an expression if the token can begin one.
|
|
fn parse_expr_opt(&mut self) -> PResult<'a, Option<P<Expr>>> {
|
|
Ok(if self.token.can_begin_expr() { Some(self.parse_expr()?) } else { None })
|
|
}
|
|
|
|
/// Parse `"return" expr?`.
|
|
fn parse_expr_return(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let kind = ExprKind::Ret(self.parse_expr_opt()?);
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"do" "yeet" expr?`.
|
|
fn parse_expr_yeet(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
|
|
self.bump(); // `do`
|
|
self.bump(); // `yeet`
|
|
|
|
let kind = ExprKind::Yeet(self.parse_expr_opt()?);
|
|
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.gated_spans.gate(sym::yeet_expr, span);
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"break" (('label (:? expr)?) | expr?)` with `"break"` token already eaten.
|
|
/// If the label is followed immediately by a `:` token, the label and `:` are
|
|
/// parsed as part of the expression (i.e. a labeled loop). The language team has
|
|
/// decided in #87026 to require parentheses as a visual aid to avoid confusion if
|
|
/// the break expression of an unlabeled break is a labeled loop (as in
|
|
/// `break 'lbl: loop {}`); a labeled break with an unlabeled loop as its value
|
|
/// expression only gets a warning for compatibility reasons; and a labeled break
|
|
/// with a labeled loop does not even get a warning because there is no ambiguity.
|
|
fn parse_expr_break(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let mut label = self.eat_label();
|
|
let kind = if self.token == token::Colon && let Some(label) = label.take() {
|
|
// The value expression can be a labeled loop, see issue #86948, e.g.:
|
|
// `loop { break 'label: loop { break 'label 42; }; }`
|
|
let lexpr = self.parse_expr_labeled(label, true)?;
|
|
self.sess.emit_err(errors::LabeledLoopInBreak {
|
|
span: lexpr.span,
|
|
sub: errors::WrapExpressionInParentheses {
|
|
left: lexpr.span.shrink_to_lo(),
|
|
right: lexpr.span.shrink_to_hi(),
|
|
},
|
|
});
|
|
Some(lexpr)
|
|
} else if self.token != token::OpenDelim(Delimiter::Brace)
|
|
|| !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
|
{
|
|
let mut expr = self.parse_expr_opt()?;
|
|
if let Some(expr) = &mut expr {
|
|
if label.is_some()
|
|
&& matches!(
|
|
expr.kind,
|
|
ExprKind::While(_, _, None)
|
|
| ExprKind::ForLoop(_, _, _, None)
|
|
| ExprKind::Loop(_, None, _)
|
|
| ExprKind::Block(_, None)
|
|
)
|
|
{
|
|
self.sess.buffer_lint_with_diagnostic(
|
|
BREAK_WITH_LABEL_AND_LOOP,
|
|
lo.to(expr.span),
|
|
ast::CRATE_NODE_ID,
|
|
"this labeled break expression is easy to confuse with an unlabeled break with a labeled value expression",
|
|
BuiltinLintDiagnostics::BreakWithLabelAndLoop(expr.span),
|
|
);
|
|
}
|
|
|
|
// Recover `break label aaaaa`
|
|
if self.may_recover()
|
|
&& let ExprKind::Path(None, p) = &expr.kind
|
|
&& let [segment] = &*p.segments
|
|
&& let &ast::PathSegment { ident, args: None, .. } = segment
|
|
&& let Some(next) = self.parse_expr_opt()?
|
|
{
|
|
label = Some(self.recover_ident_into_label(ident));
|
|
*expr = next;
|
|
}
|
|
}
|
|
|
|
expr
|
|
} else {
|
|
None
|
|
};
|
|
let expr = self.mk_expr(lo.to(self.prev_token.span), ExprKind::Break(label, kind));
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Parse `"continue" label?`.
|
|
fn parse_expr_continue(&mut self, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let mut label = self.eat_label();
|
|
|
|
// Recover `continue label` -> `continue 'label`
|
|
if self.may_recover()
|
|
&& label.is_none()
|
|
&& let Some((ident, _)) = self.token.ident()
|
|
{
|
|
self.bump();
|
|
label = Some(self.recover_ident_into_label(ident));
|
|
}
|
|
|
|
let kind = ExprKind::Continue(label);
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), kind))
|
|
}
|
|
|
|
/// Parse `"yield" expr?`.
|
|
fn parse_expr_yield(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let kind = ExprKind::Yield(self.parse_expr_opt()?);
|
|
let span = lo.to(self.prev_token.span);
|
|
self.sess.gated_spans.gate(sym::generators, span);
|
|
let expr = self.mk_expr(span, kind);
|
|
self.maybe_recover_from_bad_qpath(expr)
|
|
}
|
|
|
|
/// Returns a string literal if the next token is a string literal.
|
|
/// In case of error returns `Some(lit)` if the next token is a literal with a wrong kind,
|
|
/// and returns `None` if the next token is not literal at all.
|
|
pub fn parse_str_lit(&mut self) -> Result<ast::StrLit, Option<MetaItemLit>> {
|
|
match self.parse_opt_meta_item_lit() {
|
|
Some(lit) => match lit.kind {
|
|
ast::LitKind::Str(symbol_unescaped, style) => Ok(ast::StrLit {
|
|
style,
|
|
symbol: lit.symbol,
|
|
suffix: lit.suffix,
|
|
span: lit.span,
|
|
symbol_unescaped,
|
|
}),
|
|
_ => Err(Some(lit)),
|
|
},
|
|
None => Err(None),
|
|
}
|
|
}
|
|
|
|
pub(crate) fn mk_token_lit_char(name: Symbol, span: Span) -> (token::Lit, Span) {
|
|
(token::Lit { symbol: name, suffix: None, kind: token::Char }, span)
|
|
}
|
|
|
|
fn mk_meta_item_lit_char(name: Symbol, span: Span) -> MetaItemLit {
|
|
ast::MetaItemLit {
|
|
symbol: name,
|
|
suffix: None,
|
|
kind: ast::LitKind::Char(name.as_str().chars().next().unwrap_or('_')),
|
|
span,
|
|
}
|
|
}
|
|
|
|
fn handle_missing_lit<L>(
|
|
&mut self,
|
|
mk_lit_char: impl FnOnce(Symbol, Span) -> L,
|
|
) -> PResult<'a, L> {
|
|
if let token::Interpolated(nt) = &self.token.kind
|
|
&& let token::NtExpr(e) | token::NtLiteral(e) = &**nt
|
|
&& matches!(e.kind, ExprKind::Err)
|
|
{
|
|
let mut err = errors::InvalidInterpolatedExpression { span: self.token.span }
|
|
.into_diagnostic(&self.sess.span_diagnostic);
|
|
err.downgrade_to_delayed_bug();
|
|
return Err(err);
|
|
}
|
|
let token = self.token.clone();
|
|
let err = |self_: &Self| {
|
|
let msg = format!("unexpected token: {}", super::token_descr(&token));
|
|
self_.struct_span_err(token.span, &msg)
|
|
};
|
|
// On an error path, eagerly consider a lifetime to be an unclosed character lit
|
|
if self.token.is_lifetime() {
|
|
let lt = self.expect_lifetime();
|
|
Ok(self.recover_unclosed_char(lt.ident, mk_lit_char, err))
|
|
} else {
|
|
Err(err(self))
|
|
}
|
|
}
|
|
|
|
pub(super) fn parse_token_lit(&mut self) -> PResult<'a, (token::Lit, Span)> {
|
|
self.parse_opt_token_lit()
|
|
.ok_or(())
|
|
.or_else(|()| self.handle_missing_lit(Parser::mk_token_lit_char))
|
|
}
|
|
|
|
pub(super) fn parse_meta_item_lit(&mut self) -> PResult<'a, MetaItemLit> {
|
|
self.parse_opt_meta_item_lit()
|
|
.ok_or(())
|
|
.or_else(|()| self.handle_missing_lit(Parser::mk_meta_item_lit_char))
|
|
}
|
|
|
|
fn recover_after_dot(&mut self) -> Option<Token> {
|
|
let mut recovered = None;
|
|
if self.token == token::Dot {
|
|
// Attempt to recover `.4` as `0.4`. We don't currently have any syntax where
|
|
// dot would follow an optional literal, so we do this unconditionally.
|
|
recovered = self.look_ahead(1, |next_token| {
|
|
if let token::Literal(token::Lit { kind: token::Integer, symbol, suffix }) =
|
|
next_token.kind
|
|
{
|
|
// If this integer looks like a float, then recover as such.
|
|
//
|
|
// We will never encounter the exponent part of a floating
|
|
// point literal here, since there's no use of the exponent
|
|
// syntax that also constitutes a valid integer, so we need
|
|
// not check for that.
|
|
if suffix.map_or(true, |s| s == sym::f32 || s == sym::f64)
|
|
&& symbol.as_str().chars().all(|c| c.is_numeric() || c == '_')
|
|
&& self.token.span.hi() == next_token.span.lo()
|
|
{
|
|
let s = String::from("0.") + symbol.as_str();
|
|
let kind = TokenKind::lit(token::Float, Symbol::intern(&s), suffix);
|
|
return Some(Token::new(kind, self.token.span.to(next_token.span)));
|
|
}
|
|
}
|
|
None
|
|
});
|
|
if let Some(token) = &recovered {
|
|
self.bump();
|
|
self.sess.emit_err(errors::FloatLiteralRequiresIntegerPart {
|
|
span: token.span,
|
|
correct: pprust::token_to_string(token).into_owned(),
|
|
});
|
|
}
|
|
}
|
|
|
|
recovered
|
|
}
|
|
|
|
/// Matches `lit = true | false | token_lit`.
|
|
/// Returns `None` if the next token is not a literal.
|
|
pub(super) fn parse_opt_token_lit(&mut self) -> Option<(token::Lit, Span)> {
|
|
let recovered = self.recover_after_dot();
|
|
let token = recovered.as_ref().unwrap_or(&self.token);
|
|
let span = token.span;
|
|
token::Lit::from_token(token).map(|token_lit| {
|
|
self.bump();
|
|
(token_lit, span)
|
|
})
|
|
}
|
|
|
|
/// Matches `lit = true | false | token_lit`.
|
|
/// Returns `None` if the next token is not a literal.
|
|
pub(super) fn parse_opt_meta_item_lit(&mut self) -> Option<MetaItemLit> {
|
|
let recovered = self.recover_after_dot();
|
|
let token = recovered.as_ref().unwrap_or(&self.token);
|
|
match token::Lit::from_token(token) {
|
|
Some(token_lit) => {
|
|
match MetaItemLit::from_token_lit(token_lit, token.span) {
|
|
Ok(lit) => {
|
|
self.bump();
|
|
Some(lit)
|
|
}
|
|
Err(err) => {
|
|
let span = token.span;
|
|
let token::Literal(lit) = token.kind else {
|
|
unreachable!();
|
|
};
|
|
self.bump();
|
|
report_lit_error(&self.sess, err, lit, span);
|
|
// Pack possible quotes and prefixes from the original literal into
|
|
// the error literal's symbol so they can be pretty-printed faithfully.
|
|
let suffixless_lit = token::Lit::new(lit.kind, lit.symbol, None);
|
|
let symbol = Symbol::intern(&suffixless_lit.to_string());
|
|
let lit = token::Lit::new(token::Err, symbol, lit.suffix);
|
|
Some(
|
|
MetaItemLit::from_token_lit(lit, span)
|
|
.unwrap_or_else(|_| unreachable!()),
|
|
)
|
|
}
|
|
}
|
|
}
|
|
None => None,
|
|
}
|
|
}
|
|
|
|
pub(super) fn expect_no_tuple_index_suffix(&self, span: Span, suffix: Symbol) {
|
|
if [sym::i32, sym::u32, sym::isize, sym::usize].contains(&suffix) {
|
|
// #59553: warn instead of reject out of hand to allow the fix to percolate
|
|
// through the ecosystem when people fix their macros
|
|
self.sess.emit_warning(errors::InvalidLiteralSuffixOnTupleIndex {
|
|
span,
|
|
suffix,
|
|
exception: Some(()),
|
|
});
|
|
} else {
|
|
self.sess.emit_err(errors::InvalidLiteralSuffixOnTupleIndex {
|
|
span,
|
|
suffix,
|
|
exception: None,
|
|
});
|
|
}
|
|
}
|
|
|
|
/// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
|
|
/// Keep this in sync with `Token::can_begin_literal_maybe_minus`.
|
|
pub fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
|
|
maybe_whole_expr!(self);
|
|
|
|
let lo = self.token.span;
|
|
let minus_present = self.eat(&token::BinOp(token::Minus));
|
|
let (token_lit, span) = self.parse_token_lit()?;
|
|
let expr = self.mk_expr(span, ExprKind::Lit(token_lit));
|
|
|
|
if minus_present {
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), self.mk_unary(UnOp::Neg, expr)))
|
|
} else {
|
|
Ok(expr)
|
|
}
|
|
}
|
|
|
|
fn is_array_like_block(&mut self) -> bool {
|
|
self.look_ahead(1, |t| matches!(t.kind, TokenKind::Ident(..) | TokenKind::Literal(_)))
|
|
&& self.look_ahead(2, |t| t == &token::Comma)
|
|
&& self.look_ahead(3, |t| t.can_begin_expr())
|
|
}
|
|
|
|
/// Emits a suggestion if it looks like the user meant an array but
|
|
/// accidentally used braces, causing the code to be interpreted as a block
|
|
/// expression.
|
|
fn maybe_suggest_brackets_instead_of_braces(&mut self, lo: Span) -> Option<P<Expr>> {
|
|
let mut snapshot = self.create_snapshot_for_diagnostic();
|
|
match snapshot.parse_expr_array_or_repeat(Delimiter::Brace) {
|
|
Ok(arr) => {
|
|
self.sess.emit_err(errors::ArrayBracketsInsteadOfSpaces {
|
|
span: arr.span,
|
|
sub: errors::ArrayBracketsInsteadOfSpacesSugg {
|
|
left: lo,
|
|
right: snapshot.prev_token.span,
|
|
},
|
|
});
|
|
|
|
self.restore_snapshot(snapshot);
|
|
Some(self.mk_expr_err(arr.span))
|
|
}
|
|
Err(e) => {
|
|
e.cancel();
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
fn suggest_missing_semicolon_before_array(
|
|
&self,
|
|
prev_span: Span,
|
|
open_delim_span: Span,
|
|
) -> PResult<'a, ()> {
|
|
if !self.may_recover() {
|
|
return Ok(());
|
|
}
|
|
|
|
if self.token.kind == token::Comma {
|
|
if !self.sess.source_map().is_multiline(prev_span.until(self.token.span)) {
|
|
return Ok(());
|
|
}
|
|
let mut snapshot = self.create_snapshot_for_diagnostic();
|
|
snapshot.bump();
|
|
match snapshot.parse_seq_to_before_end(
|
|
&token::CloseDelim(Delimiter::Bracket),
|
|
SeqSep::trailing_allowed(token::Comma),
|
|
|p| p.parse_expr(),
|
|
) {
|
|
Ok(_)
|
|
// When the close delim is `)`, `token.kind` is expected to be `token::CloseDelim(Delimiter::Parenthesis)`,
|
|
// but the actual `token.kind` is `token::CloseDelim(Delimiter::Bracket)`.
|
|
// This is because the `token.kind` of the close delim is treated as the same as
|
|
// that of the open delim in `TokenTreesReader::parse_token_tree`, even if the delimiters of them are different.
|
|
// Therefore, `token.kind` should not be compared here.
|
|
if snapshot
|
|
.span_to_snippet(snapshot.token.span)
|
|
.map_or(false, |snippet| snippet == "]") =>
|
|
{
|
|
return Err(errors::MissingSemicolonBeforeArray {
|
|
open_delim: open_delim_span,
|
|
semicolon: prev_span.shrink_to_hi(),
|
|
}.into_diagnostic(&self.sess.span_diagnostic));
|
|
}
|
|
Ok(_) => (),
|
|
Err(err) => err.cancel(),
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
/// Parses a block or unsafe block.
|
|
pub(super) fn parse_expr_block(
|
|
&mut self,
|
|
opt_label: Option<Label>,
|
|
lo: Span,
|
|
blk_mode: BlockCheckMode,
|
|
) -> PResult<'a, P<Expr>> {
|
|
if self.may_recover() && self.is_array_like_block() {
|
|
if let Some(arr) = self.maybe_suggest_brackets_instead_of_braces(lo) {
|
|
return Ok(arr);
|
|
}
|
|
}
|
|
|
|
if self.token.is_whole_block() {
|
|
self.sess.emit_err(errors::InvalidBlockMacroSegment {
|
|
span: self.token.span,
|
|
context: lo.to(self.token.span),
|
|
});
|
|
}
|
|
|
|
let (attrs, blk) = self.parse_block_common(lo, blk_mode, true)?;
|
|
Ok(self.mk_expr_with_attrs(blk.span, ExprKind::Block(blk, opt_label), attrs))
|
|
}
|
|
|
|
/// Parse a block which takes no attributes and has no label
|
|
fn parse_simple_block(&mut self) -> PResult<'a, P<Expr>> {
|
|
let blk = self.parse_block()?;
|
|
Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None)))
|
|
}
|
|
|
|
/// Parses a closure expression (e.g., `move |args| expr`).
|
|
fn parse_expr_closure(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
|
|
let binder = if self.check_keyword(kw::For) {
|
|
let lo = self.token.span;
|
|
let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
|
|
let span = lo.to(self.prev_token.span);
|
|
|
|
self.sess.gated_spans.gate(sym::closure_lifetime_binder, span);
|
|
|
|
ClosureBinder::For { span, generic_params: lifetime_defs }
|
|
} else {
|
|
ClosureBinder::NotPresent
|
|
};
|
|
|
|
let constness = self.parse_closure_constness();
|
|
|
|
let movability =
|
|
if self.eat_keyword(kw::Static) { Movability::Static } else { Movability::Movable };
|
|
|
|
let asyncness = if self.token.uninterpolated_span().rust_2018() {
|
|
self.parse_asyncness(Case::Sensitive)
|
|
} else {
|
|
Async::No
|
|
};
|
|
|
|
let capture_clause = self.parse_capture_clause()?;
|
|
let (fn_decl, fn_arg_span) = self.parse_fn_block_decl()?;
|
|
let decl_hi = self.prev_token.span;
|
|
let mut body = match fn_decl.output {
|
|
FnRetTy::Default(_) => {
|
|
let restrictions = self.restrictions - Restrictions::STMT_EXPR;
|
|
self.parse_expr_res(restrictions, None)?
|
|
}
|
|
_ => {
|
|
// If an explicit return type is given, require a block to appear (RFC 968).
|
|
let body_lo = self.token.span;
|
|
self.parse_expr_block(None, body_lo, BlockCheckMode::Default)?
|
|
}
|
|
};
|
|
|
|
if let Async::Yes { span, .. } = asyncness {
|
|
// Feature-gate `async ||` closures.
|
|
self.sess.gated_spans.gate(sym::async_closure, span);
|
|
}
|
|
|
|
if self.token.kind == TokenKind::Semi
|
|
&& matches!(self.token_cursor.stack.last(), Some((_, Delimiter::Parenthesis, _)))
|
|
&& self.may_recover()
|
|
{
|
|
// It is likely that the closure body is a block but where the
|
|
// braces have been removed. We will recover and eat the next
|
|
// statements later in the parsing process.
|
|
body = self.mk_expr_err(body.span);
|
|
}
|
|
|
|
let body_span = body.span;
|
|
|
|
let closure = self.mk_expr(
|
|
lo.to(body.span),
|
|
ExprKind::Closure(Box::new(ast::Closure {
|
|
binder,
|
|
capture_clause,
|
|
constness,
|
|
asyncness,
|
|
movability,
|
|
fn_decl,
|
|
body,
|
|
fn_decl_span: lo.to(decl_hi),
|
|
fn_arg_span,
|
|
})),
|
|
);
|
|
|
|
// Disable recovery for closure body
|
|
let spans =
|
|
ClosureSpans { whole_closure: closure.span, closing_pipe: decl_hi, body: body_span };
|
|
self.current_closure = Some(spans);
|
|
|
|
Ok(closure)
|
|
}
|
|
|
|
/// Parses an optional `move` prefix to a closure-like construct.
|
|
fn parse_capture_clause(&mut self) -> PResult<'a, CaptureBy> {
|
|
if self.eat_keyword(kw::Move) {
|
|
// Check for `move async` and recover
|
|
if self.check_keyword(kw::Async) {
|
|
let move_async_span = self.token.span.with_lo(self.prev_token.span.data().lo);
|
|
Err(errors::AsyncMoveOrderIncorrect { span: move_async_span }
|
|
.into_diagnostic(&self.sess.span_diagnostic))
|
|
} else {
|
|
Ok(CaptureBy::Value)
|
|
}
|
|
} else {
|
|
Ok(CaptureBy::Ref)
|
|
}
|
|
}
|
|
|
|
/// Parses the `|arg, arg|` header of a closure.
|
|
fn parse_fn_block_decl(&mut self) -> PResult<'a, (P<FnDecl>, Span)> {
|
|
let arg_start = self.token.span.lo();
|
|
|
|
let inputs = if self.eat(&token::OrOr) {
|
|
ThinVec::new()
|
|
} else {
|
|
self.expect(&token::BinOp(token::Or))?;
|
|
let args = self
|
|
.parse_seq_to_before_tokens(
|
|
&[&token::BinOp(token::Or), &token::OrOr],
|
|
SeqSep::trailing_allowed(token::Comma),
|
|
TokenExpectType::NoExpect,
|
|
|p| p.parse_fn_block_param(),
|
|
)?
|
|
.0;
|
|
self.expect_or()?;
|
|
args
|
|
};
|
|
let arg_span = self.prev_token.span.with_lo(arg_start);
|
|
let output =
|
|
self.parse_ret_ty(AllowPlus::Yes, RecoverQPath::Yes, RecoverReturnSign::Yes)?;
|
|
|
|
Ok((P(FnDecl { inputs, output }), arg_span))
|
|
}
|
|
|
|
/// Parses a parameter in a closure header (e.g., `|arg, arg|`).
|
|
fn parse_fn_block_param(&mut self) -> PResult<'a, Param> {
|
|
let lo = self.token.span;
|
|
let attrs = self.parse_outer_attributes()?;
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let pat = this.parse_pat_no_top_alt(Some(Expected::ParameterName))?;
|
|
let ty = if this.eat(&token::Colon) {
|
|
this.parse_ty()?
|
|
} else {
|
|
this.mk_ty(this.prev_token.span, TyKind::Infer)
|
|
};
|
|
|
|
Ok((
|
|
Param {
|
|
attrs,
|
|
ty,
|
|
pat,
|
|
span: lo.to(this.prev_token.span),
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::MaybeComma,
|
|
))
|
|
})
|
|
}
|
|
|
|
/// Parses an `if` expression (`if` token already eaten).
|
|
fn parse_expr_if(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.prev_token.span;
|
|
let cond = self.parse_expr_cond()?;
|
|
self.parse_if_after_cond(lo, cond)
|
|
}
|
|
|
|
fn parse_if_after_cond(&mut self, lo: Span, mut cond: P<Expr>) -> PResult<'a, P<Expr>> {
|
|
let cond_span = cond.span;
|
|
// Tries to interpret `cond` as either a missing expression if it's a block,
|
|
// or as an unfinished expression if it's a binop and the RHS is a block.
|
|
// We could probably add more recoveries here too...
|
|
let mut recover_block_from_condition = |this: &mut Self| {
|
|
let block = match &mut cond.kind {
|
|
ExprKind::Binary(Spanned { span: binop_span, .. }, _, right)
|
|
if let ExprKind::Block(_, None) = right.kind => {
|
|
self.sess.emit_err(errors::IfExpressionMissingThenBlock {
|
|
if_span: lo,
|
|
missing_then_block_sub:
|
|
errors::IfExpressionMissingThenBlockSub::UnfinishedCondition(cond_span.shrink_to_lo().to(*binop_span)),
|
|
let_else_sub: None,
|
|
|
|
});
|
|
std::mem::replace(right, this.mk_expr_err(binop_span.shrink_to_hi()))
|
|
},
|
|
ExprKind::Block(_, None) => {
|
|
self.sess.emit_err(errors::IfExpressionMissingCondition {
|
|
if_span: lo.shrink_to_hi(),
|
|
block_span: self.sess.source_map().start_point(cond_span),
|
|
});
|
|
std::mem::replace(&mut cond, this.mk_expr_err(cond_span.shrink_to_hi()))
|
|
}
|
|
_ => {
|
|
return None;
|
|
}
|
|
};
|
|
if let ExprKind::Block(block, _) = &block.kind {
|
|
Some(block.clone())
|
|
} else {
|
|
unreachable!()
|
|
}
|
|
};
|
|
// Parse then block
|
|
let thn = if self.token.is_keyword(kw::Else) {
|
|
if let Some(block) = recover_block_from_condition(self) {
|
|
block
|
|
} else {
|
|
let let_else_sub = matches!(cond.kind, ExprKind::Let(..))
|
|
.then(|| errors::IfExpressionLetSomeSub { if_span: lo.until(cond_span) });
|
|
|
|
self.sess.emit_err(errors::IfExpressionMissingThenBlock {
|
|
if_span: lo,
|
|
missing_then_block_sub: errors::IfExpressionMissingThenBlockSub::AddThenBlock(
|
|
cond_span.shrink_to_hi(),
|
|
),
|
|
let_else_sub,
|
|
});
|
|
self.mk_block_err(cond_span.shrink_to_hi())
|
|
}
|
|
} else {
|
|
let attrs = self.parse_outer_attributes()?; // For recovery.
|
|
let block = if self.check(&token::OpenDelim(Delimiter::Brace)) {
|
|
self.parse_block()?
|
|
} else {
|
|
if let Some(block) = recover_block_from_condition(self) {
|
|
block
|
|
} else {
|
|
self.error_on_extra_if(&cond)?;
|
|
// Parse block, which will always fail, but we can add a nice note to the error
|
|
self.parse_block().map_err(|mut err| {
|
|
err.span_note(
|
|
cond_span,
|
|
"the `if` expression is missing a block after this condition",
|
|
);
|
|
err
|
|
})?
|
|
}
|
|
};
|
|
self.error_on_if_block_attrs(lo, false, block.span, attrs);
|
|
block
|
|
};
|
|
let els = if self.eat_keyword(kw::Else) { Some(self.parse_expr_else()?) } else { None };
|
|
Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::If(cond, thn, els)))
|
|
}
|
|
|
|
/// Parses the condition of a `if` or `while` expression.
|
|
fn parse_expr_cond(&mut self) -> PResult<'a, P<Expr>> {
|
|
let cond =
|
|
self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL | Restrictions::ALLOW_LET, None)?;
|
|
|
|
if let ExprKind::Let(..) = cond.kind {
|
|
// Remove the last feature gating of a `let` expression since it's stable.
|
|
self.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
|
|
}
|
|
|
|
Ok(cond)
|
|
}
|
|
|
|
/// Parses a `let $pat = $expr` pseudo-expression.
|
|
fn parse_expr_let(&mut self) -> PResult<'a, P<Expr>> {
|
|
// This is a *approximate* heuristic that detects if `let` chains are
|
|
// being parsed in the right position. It's approximate because it
|
|
// doesn't deny all invalid `let` expressions, just completely wrong usages.
|
|
let not_in_chain = !matches!(
|
|
self.prev_token.kind,
|
|
TokenKind::AndAnd | TokenKind::Ident(kw::If, _) | TokenKind::Ident(kw::While, _)
|
|
);
|
|
if !self.restrictions.contains(Restrictions::ALLOW_LET) || not_in_chain {
|
|
self.sess.emit_err(errors::ExpectedExpressionFoundLet { span: self.token.span });
|
|
}
|
|
|
|
self.bump(); // Eat `let` token
|
|
let lo = self.prev_token.span;
|
|
let pat = self.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::LikelyTuple,
|
|
)?;
|
|
if self.token == token::EqEq {
|
|
self.sess.emit_err(errors::ExpectedEqForLetExpr {
|
|
span: self.token.span,
|
|
sugg_span: self.token.span,
|
|
});
|
|
self.bump();
|
|
} else {
|
|
self.expect(&token::Eq)?;
|
|
}
|
|
let expr = self.with_res(self.restrictions | Restrictions::NO_STRUCT_LITERAL, |this| {
|
|
this.parse_expr_assoc_with(1 + prec_let_scrutinee_needs_par(), None.into())
|
|
})?;
|
|
let span = lo.to(expr.span);
|
|
self.sess.gated_spans.gate(sym::let_chains, span);
|
|
Ok(self.mk_expr(span, ExprKind::Let(pat, expr, span)))
|
|
}
|
|
|
|
/// Parses an `else { ... }` expression (`else` token already eaten).
|
|
fn parse_expr_else(&mut self) -> PResult<'a, P<Expr>> {
|
|
let else_span = self.prev_token.span; // `else`
|
|
let attrs = self.parse_outer_attributes()?; // For recovery.
|
|
let expr = if self.eat_keyword(kw::If) {
|
|
self.parse_expr_if()?
|
|
} else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
|
|
self.parse_simple_block()?
|
|
} else {
|
|
let snapshot = self.create_snapshot_for_diagnostic();
|
|
let first_tok = super::token_descr(&self.token);
|
|
let first_tok_span = self.token.span;
|
|
match self.parse_expr() {
|
|
Ok(cond)
|
|
// If it's not a free-standing expression, and is followed by a block,
|
|
// then it's very likely the condition to an `else if`.
|
|
if self.check(&TokenKind::OpenDelim(Delimiter::Brace))
|
|
&& classify::expr_requires_semi_to_be_stmt(&cond) =>
|
|
{
|
|
self.sess.emit_err(errors::ExpectedElseBlock {
|
|
first_tok_span,
|
|
first_tok,
|
|
else_span,
|
|
condition_start: cond.span.shrink_to_lo(),
|
|
});
|
|
self.parse_if_after_cond(cond.span.shrink_to_lo(), cond)?
|
|
}
|
|
Err(e) => {
|
|
e.cancel();
|
|
self.restore_snapshot(snapshot);
|
|
self.parse_simple_block()?
|
|
},
|
|
Ok(_) => {
|
|
self.restore_snapshot(snapshot);
|
|
self.parse_simple_block()?
|
|
},
|
|
}
|
|
};
|
|
self.error_on_if_block_attrs(else_span, true, expr.span, attrs);
|
|
Ok(expr)
|
|
}
|
|
|
|
fn error_on_if_block_attrs(
|
|
&self,
|
|
ctx_span: Span,
|
|
is_ctx_else: bool,
|
|
branch_span: Span,
|
|
attrs: AttrWrapper,
|
|
) {
|
|
if attrs.is_empty() {
|
|
return;
|
|
}
|
|
|
|
let attrs: &[ast::Attribute] = &attrs.take_for_recovery(self.sess);
|
|
let (attributes, last) = match attrs {
|
|
[] => return,
|
|
[x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),
|
|
};
|
|
let ctx = if is_ctx_else { "else" } else { "if" };
|
|
self.sess.emit_err(errors::OuterAttributeNotAllowedOnIfElse {
|
|
last,
|
|
branch_span,
|
|
ctx_span,
|
|
ctx: ctx.to_string(),
|
|
attributes,
|
|
});
|
|
}
|
|
|
|
fn error_on_extra_if(&mut self, cond: &P<Expr>) -> PResult<'a, ()> {
|
|
if let ExprKind::Binary(Spanned { span: binop_span, node: binop}, _, right) = &cond.kind &&
|
|
let BinOpKind::And = binop &&
|
|
let ExprKind::If(cond, ..) = &right.kind {
|
|
Err(self.sess.create_err(errors::UnexpectedIfWithIf(binop_span.shrink_to_hi().to(cond.span.shrink_to_lo()))))
|
|
} else {
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
|
|
fn parse_expr_for(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
// Record whether we are about to parse `for (`.
|
|
// This is used below for recovery in case of `for ( $stuff ) $block`
|
|
// in which case we will suggest `for $stuff $block`.
|
|
let begin_paren = match self.token.kind {
|
|
token::OpenDelim(Delimiter::Parenthesis) => Some(self.token.span),
|
|
_ => None,
|
|
};
|
|
|
|
let pat = self.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::LikelyTuple,
|
|
)?;
|
|
if !self.eat_keyword(kw::In) {
|
|
self.error_missing_in_for_loop();
|
|
}
|
|
self.check_for_for_in_in_typo(self.prev_token.span);
|
|
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
|
|
|
let pat = self.recover_parens_around_for_head(pat, begin_paren);
|
|
|
|
// Recover from missing expression in `for` loop
|
|
if matches!(expr.kind, ExprKind::Block(..))
|
|
&& !matches!(self.token.kind, token::OpenDelim(token::Delimiter::Brace))
|
|
&& self.may_recover()
|
|
{
|
|
self.sess
|
|
.emit_err(errors::MissingExpressionInForLoop { span: expr.span.shrink_to_lo() });
|
|
let err_expr = self.mk_expr(expr.span, ExprKind::Err);
|
|
let block = self.mk_block(thin_vec![], BlockCheckMode::Default, self.prev_token.span);
|
|
return Ok(self.mk_expr(
|
|
lo.to(self.prev_token.span),
|
|
ExprKind::ForLoop(pat, err_expr, block, opt_label),
|
|
));
|
|
}
|
|
|
|
let (attrs, loop_block) = self.parse_inner_attrs_and_block()?;
|
|
|
|
let kind = ExprKind::ForLoop(pat, expr, loop_block, opt_label);
|
|
|
|
self.recover_loop_else("for", lo)?;
|
|
|
|
Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
|
|
}
|
|
|
|
/// Recovers from an `else` clause after a loop (`for...else`, `while...else`)
|
|
fn recover_loop_else(&mut self, loop_kind: &'static str, loop_kw: Span) -> PResult<'a, ()> {
|
|
if self.token.is_keyword(kw::Else) && self.may_recover() {
|
|
let else_span = self.token.span;
|
|
self.bump();
|
|
let else_clause = self.parse_expr_else()?;
|
|
self.sess.emit_err(errors::LoopElseNotSupported {
|
|
span: else_span.to(else_clause.span),
|
|
loop_kind,
|
|
loop_kw,
|
|
});
|
|
}
|
|
Ok(())
|
|
}
|
|
|
|
fn error_missing_in_for_loop(&mut self) {
|
|
let (span, sub): (_, fn(_) -> _) = if self.token.is_ident_named(sym::of) {
|
|
// Possibly using JS syntax (#75311).
|
|
let span = self.token.span;
|
|
self.bump();
|
|
(span, errors::MissingInInForLoopSub::InNotOf)
|
|
} else {
|
|
(self.prev_token.span.between(self.token.span), errors::MissingInInForLoopSub::AddIn)
|
|
};
|
|
|
|
self.sess.emit_err(errors::MissingInInForLoop { span, sub: sub(span) });
|
|
}
|
|
|
|
/// Parses a `while` or `while let` expression (`while` token already eaten).
|
|
fn parse_expr_while(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let cond = self.parse_expr_cond().map_err(|mut err| {
|
|
err.span_label(lo, "while parsing the condition of this `while` expression");
|
|
err
|
|
})?;
|
|
let (attrs, body) = self.parse_inner_attrs_and_block().map_err(|mut err| {
|
|
err.span_label(lo, "while parsing the body of this `while` expression");
|
|
err.span_label(cond.span, "this `while` condition successfully parsed");
|
|
err
|
|
})?;
|
|
|
|
self.recover_loop_else("while", lo)?;
|
|
|
|
Ok(self.mk_expr_with_attrs(
|
|
lo.to(self.prev_token.span),
|
|
ExprKind::While(cond, body, opt_label),
|
|
attrs,
|
|
))
|
|
}
|
|
|
|
/// Parses `loop { ... }` (`loop` token already eaten).
|
|
fn parse_expr_loop(&mut self, opt_label: Option<Label>, lo: Span) -> PResult<'a, P<Expr>> {
|
|
let loop_span = self.prev_token.span;
|
|
let (attrs, body) = self.parse_inner_attrs_and_block()?;
|
|
self.recover_loop_else("loop", lo)?;
|
|
Ok(self.mk_expr_with_attrs(
|
|
lo.to(self.prev_token.span),
|
|
ExprKind::Loop(body, opt_label, loop_span),
|
|
attrs,
|
|
))
|
|
}
|
|
|
|
pub(crate) fn eat_label(&mut self) -> Option<Label> {
|
|
self.token.lifetime().map(|ident| {
|
|
self.bump();
|
|
Label { ident }
|
|
})
|
|
}
|
|
|
|
/// Parses a `match ... { ... }` expression (`match` token already eaten).
|
|
fn parse_expr_match(&mut self) -> PResult<'a, P<Expr>> {
|
|
let match_span = self.prev_token.span;
|
|
let lo = self.prev_token.span;
|
|
let scrutinee = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
|
|
if let Err(mut e) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
|
|
if self.token == token::Semi {
|
|
e.span_suggestion_short(
|
|
match_span,
|
|
"try removing this `match`",
|
|
"",
|
|
Applicability::MaybeIncorrect, // speculative
|
|
);
|
|
}
|
|
if self.maybe_recover_unexpected_block_label() {
|
|
e.cancel();
|
|
self.bump();
|
|
} else {
|
|
return Err(e);
|
|
}
|
|
}
|
|
let attrs = self.parse_inner_attributes()?;
|
|
|
|
let mut arms = ThinVec::new();
|
|
while self.token != token::CloseDelim(Delimiter::Brace) {
|
|
match self.parse_arm() {
|
|
Ok(arm) => arms.push(arm),
|
|
Err(mut e) => {
|
|
// Recover by skipping to the end of the block.
|
|
e.emit();
|
|
self.recover_stmt();
|
|
let span = lo.to(self.token.span);
|
|
if self.token == token::CloseDelim(Delimiter::Brace) {
|
|
self.bump();
|
|
}
|
|
return Ok(self.mk_expr_with_attrs(
|
|
span,
|
|
ExprKind::Match(scrutinee, arms),
|
|
attrs,
|
|
));
|
|
}
|
|
}
|
|
}
|
|
let hi = self.token.span;
|
|
self.bump();
|
|
Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms), attrs))
|
|
}
|
|
|
|
/// Attempt to recover from match arm body with statements and no surrounding braces.
|
|
fn parse_arm_body_missing_braces(
|
|
&mut self,
|
|
first_expr: &P<Expr>,
|
|
arrow_span: Span,
|
|
) -> Option<P<Expr>> {
|
|
if self.token.kind != token::Semi {
|
|
return None;
|
|
}
|
|
let start_snapshot = self.create_snapshot_for_diagnostic();
|
|
let semi_sp = self.token.span;
|
|
self.bump(); // `;`
|
|
let mut stmts =
|
|
vec![self.mk_stmt(first_expr.span, ast::StmtKind::Expr(first_expr.clone()))];
|
|
let err = |this: &Parser<'_>, stmts: Vec<ast::Stmt>| {
|
|
let span = stmts[0].span.to(stmts[stmts.len() - 1].span);
|
|
|
|
this.sess.emit_err(errors::MatchArmBodyWithoutBraces {
|
|
statements: span,
|
|
arrow: arrow_span,
|
|
num_statements: stmts.len(),
|
|
sub: if stmts.len() > 1 {
|
|
errors::MatchArmBodyWithoutBracesSugg::AddBraces {
|
|
left: span.shrink_to_lo(),
|
|
right: span.shrink_to_hi(),
|
|
}
|
|
} else {
|
|
errors::MatchArmBodyWithoutBracesSugg::UseComma { semicolon: semi_sp }
|
|
},
|
|
});
|
|
this.mk_expr_err(span)
|
|
};
|
|
// We might have either a `,` -> `;` typo, or a block without braces. We need
|
|
// a more subtle parsing strategy.
|
|
loop {
|
|
if self.token.kind == token::CloseDelim(Delimiter::Brace) {
|
|
// We have reached the closing brace of the `match` expression.
|
|
return Some(err(self, stmts));
|
|
}
|
|
if self.token.kind == token::Comma {
|
|
self.restore_snapshot(start_snapshot);
|
|
return None;
|
|
}
|
|
let pre_pat_snapshot = self.create_snapshot_for_diagnostic();
|
|
match self.parse_pat_no_top_alt(None) {
|
|
Ok(_pat) => {
|
|
if self.token.kind == token::FatArrow {
|
|
// Reached arm end.
|
|
self.restore_snapshot(pre_pat_snapshot);
|
|
return Some(err(self, stmts));
|
|
}
|
|
}
|
|
Err(err) => {
|
|
err.cancel();
|
|
}
|
|
}
|
|
|
|
self.restore_snapshot(pre_pat_snapshot);
|
|
match self.parse_stmt_without_recovery(true, ForceCollect::No) {
|
|
// Consume statements for as long as possible.
|
|
Ok(Some(stmt)) => {
|
|
stmts.push(stmt);
|
|
}
|
|
Ok(None) => {
|
|
self.restore_snapshot(start_snapshot);
|
|
break;
|
|
}
|
|
// We couldn't parse either yet another statement missing it's
|
|
// enclosing block nor the next arm's pattern or closing brace.
|
|
Err(stmt_err) => {
|
|
stmt_err.cancel();
|
|
self.restore_snapshot(start_snapshot);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
pub(super) fn parse_arm(&mut self) -> PResult<'a, Arm> {
|
|
// Used to check the `let_chains` and `if_let_guard` features mostly by scanning
|
|
// `&&` tokens.
|
|
fn check_let_expr(expr: &Expr) -> (bool, bool) {
|
|
match &expr.kind {
|
|
ExprKind::Binary(BinOp { node: BinOpKind::And, .. }, lhs, rhs) => {
|
|
let lhs_rslt = check_let_expr(lhs);
|
|
let rhs_rslt = check_let_expr(rhs);
|
|
(lhs_rslt.0 || rhs_rslt.0, false)
|
|
}
|
|
ExprKind::Let(..) => (true, true),
|
|
_ => (false, true),
|
|
}
|
|
}
|
|
let attrs = self.parse_outer_attributes()?;
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let lo = this.token.span;
|
|
let pat = this.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::EitherTupleOrPipe,
|
|
)?;
|
|
let guard = if this.eat_keyword(kw::If) {
|
|
let if_span = this.prev_token.span;
|
|
let cond = this.parse_expr_res(Restrictions::ALLOW_LET, None)?;
|
|
let (has_let_expr, does_not_have_bin_op) = check_let_expr(&cond);
|
|
if has_let_expr {
|
|
if does_not_have_bin_op {
|
|
// Remove the last feature gating of a `let` expression since it's stable.
|
|
this.sess.gated_spans.ungate_last(sym::let_chains, cond.span);
|
|
}
|
|
let span = if_span.to(cond.span);
|
|
this.sess.gated_spans.gate(sym::if_let_guard, span);
|
|
}
|
|
Some(cond)
|
|
} else {
|
|
None
|
|
};
|
|
let arrow_span = this.token.span;
|
|
if let Err(mut err) = this.expect(&token::FatArrow) {
|
|
// We might have a `=>` -> `=` or `->` typo (issue #89396).
|
|
if TokenKind::FatArrow
|
|
.similar_tokens()
|
|
.map_or(false, |similar_tokens| similar_tokens.contains(&this.token.kind))
|
|
{
|
|
err.span_suggestion(
|
|
this.token.span,
|
|
"try using a fat arrow here",
|
|
"=>",
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
err.emit();
|
|
this.bump();
|
|
} else if matches!(
|
|
(&this.prev_token.kind, &this.token.kind),
|
|
(token::DotDotEq, token::Gt)
|
|
) {
|
|
// `error_inclusive_range_match_arrow` handles cases like `0..=> {}`,
|
|
// so we suppress the error here
|
|
err.delay_as_bug();
|
|
this.bump();
|
|
} else {
|
|
return Err(err);
|
|
}
|
|
}
|
|
let arm_start_span = this.token.span;
|
|
|
|
let expr = this.parse_expr_res(Restrictions::STMT_EXPR, None).map_err(|mut err| {
|
|
err.span_label(arrow_span, "while parsing the `match` arm starting here");
|
|
err
|
|
})?;
|
|
|
|
let require_comma = classify::expr_requires_semi_to_be_stmt(&expr)
|
|
&& this.token != token::CloseDelim(Delimiter::Brace);
|
|
|
|
let hi = this.prev_token.span;
|
|
|
|
if require_comma {
|
|
let sm = this.sess.source_map();
|
|
if let Some(body) = this.parse_arm_body_missing_braces(&expr, arrow_span) {
|
|
let span = body.span;
|
|
return Ok((
|
|
ast::Arm {
|
|
attrs,
|
|
pat,
|
|
guard,
|
|
body,
|
|
span,
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::None,
|
|
));
|
|
}
|
|
this.expect_one_of(&[token::Comma], &[token::CloseDelim(Delimiter::Brace)])
|
|
.or_else(|mut err| {
|
|
if this.token == token::FatArrow {
|
|
if let Ok(expr_lines) = sm.span_to_lines(expr.span)
|
|
&& let Ok(arm_start_lines) = sm.span_to_lines(arm_start_span)
|
|
&& arm_start_lines.lines[0].end_col == expr_lines.lines[0].end_col
|
|
&& expr_lines.lines.len() == 2
|
|
{
|
|
// We check whether there's any trailing code in the parse span,
|
|
// if there isn't, we very likely have the following:
|
|
//
|
|
// X | &Y => "y"
|
|
// | -- - missing comma
|
|
// | |
|
|
// | arrow_span
|
|
// X | &X => "x"
|
|
// | - ^^ self.token.span
|
|
// | |
|
|
// | parsed until here as `"y" & X`
|
|
err.span_suggestion_short(
|
|
arm_start_span.shrink_to_hi(),
|
|
"missing a comma here to end this `match` arm",
|
|
",",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
return Err(err);
|
|
}
|
|
} else {
|
|
// FIXME(compiler-errors): We could also recover `; PAT =>` here
|
|
|
|
// Try to parse a following `PAT =>`, if successful
|
|
// then we should recover.
|
|
let mut snapshot = this.create_snapshot_for_diagnostic();
|
|
let pattern_follows = snapshot
|
|
.parse_pat_allow_top_alt(
|
|
None,
|
|
RecoverComma::Yes,
|
|
RecoverColon::Yes,
|
|
CommaRecoveryMode::EitherTupleOrPipe,
|
|
)
|
|
.map_err(|err| err.cancel())
|
|
.is_ok();
|
|
if pattern_follows && snapshot.check(&TokenKind::FatArrow) {
|
|
err.cancel();
|
|
this.sess.emit_err(errors::MissingCommaAfterMatchArm {
|
|
span: hi.shrink_to_hi(),
|
|
});
|
|
return Ok(true);
|
|
}
|
|
}
|
|
err.span_label(arrow_span, "while parsing the `match` arm starting here");
|
|
Err(err)
|
|
})?;
|
|
} else {
|
|
this.eat(&token::Comma);
|
|
}
|
|
|
|
Ok((
|
|
ast::Arm {
|
|
attrs,
|
|
pat,
|
|
guard,
|
|
body: expr,
|
|
span: lo.to(hi),
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::None,
|
|
))
|
|
})
|
|
}
|
|
|
|
/// Parses a `try {...}` expression (`try` token already eaten).
|
|
fn parse_try_block(&mut self, span_lo: Span) -> PResult<'a, P<Expr>> {
|
|
let (attrs, body) = self.parse_inner_attrs_and_block()?;
|
|
if self.eat_keyword(kw::Catch) {
|
|
Err(errors::CatchAfterTry { span: self.prev_token.span }
|
|
.into_diagnostic(&self.sess.span_diagnostic))
|
|
} else {
|
|
let span = span_lo.to(body.span);
|
|
self.sess.gated_spans.gate(sym::try_blocks, span);
|
|
Ok(self.mk_expr_with_attrs(span, ExprKind::TryBlock(body), attrs))
|
|
}
|
|
}
|
|
|
|
fn is_do_catch_block(&self) -> bool {
|
|
self.token.is_keyword(kw::Do)
|
|
&& self.is_keyword_ahead(1, &[kw::Catch])
|
|
&& self.look_ahead(2, |t| *t == token::OpenDelim(Delimiter::Brace))
|
|
&& !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
|
|
}
|
|
|
|
fn is_do_yeet(&self) -> bool {
|
|
self.token.is_keyword(kw::Do) && self.is_keyword_ahead(1, &[kw::Yeet])
|
|
}
|
|
|
|
fn is_try_block(&self) -> bool {
|
|
self.token.is_keyword(kw::Try)
|
|
&& self.look_ahead(1, |t| *t == token::OpenDelim(Delimiter::Brace))
|
|
&& self.token.uninterpolated_span().rust_2018()
|
|
}
|
|
|
|
/// Parses an `async move? {...}` expression.
|
|
fn parse_async_block(&mut self) -> PResult<'a, P<Expr>> {
|
|
let lo = self.token.span;
|
|
self.expect_keyword(kw::Async)?;
|
|
let capture_clause = self.parse_capture_clause()?;
|
|
let (attrs, body) = self.parse_inner_attrs_and_block()?;
|
|
let kind = ExprKind::Async(capture_clause, body);
|
|
Ok(self.mk_expr_with_attrs(lo.to(self.prev_token.span), kind, attrs))
|
|
}
|
|
|
|
fn is_async_block(&self) -> bool {
|
|
self.token.is_keyword(kw::Async)
|
|
&& ((
|
|
// `async move {`
|
|
self.is_keyword_ahead(1, &[kw::Move])
|
|
&& self.look_ahead(2, |t| *t == token::OpenDelim(Delimiter::Brace))
|
|
) || (
|
|
// `async {`
|
|
self.look_ahead(1, |t| *t == token::OpenDelim(Delimiter::Brace))
|
|
))
|
|
}
|
|
|
|
fn is_certainly_not_a_block(&self) -> bool {
|
|
self.look_ahead(1, |t| t.is_ident())
|
|
&& (
|
|
// `{ ident, ` cannot start a block.
|
|
self.look_ahead(2, |t| t == &token::Comma)
|
|
|| self.look_ahead(2, |t| t == &token::Colon)
|
|
&& (
|
|
// `{ ident: token, ` cannot start a block.
|
|
self.look_ahead(4, |t| t == &token::Comma) ||
|
|
// `{ ident: ` cannot start a block unless it's a type ascription `ident: Type`.
|
|
self.look_ahead(3, |t| !t.can_begin_type())
|
|
)
|
|
)
|
|
}
|
|
|
|
fn maybe_parse_struct_expr(
|
|
&mut self,
|
|
qself: &Option<P<ast::QSelf>>,
|
|
path: &ast::Path,
|
|
) -> Option<PResult<'a, P<Expr>>> {
|
|
let struct_allowed = !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL);
|
|
if struct_allowed || self.is_certainly_not_a_block() {
|
|
if let Err(err) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
|
|
return Some(Err(err));
|
|
}
|
|
let expr = self.parse_expr_struct(qself.clone(), path.clone(), true);
|
|
if let (Ok(expr), false) = (&expr, struct_allowed) {
|
|
// This is a struct literal, but we don't can't accept them here.
|
|
self.sess.emit_err(errors::StructLiteralNotAllowedHere {
|
|
span: expr.span,
|
|
sub: errors::StructLiteralNotAllowedHereSugg {
|
|
left: path.span.shrink_to_lo(),
|
|
right: expr.span.shrink_to_hi(),
|
|
},
|
|
});
|
|
}
|
|
return Some(expr);
|
|
}
|
|
None
|
|
}
|
|
|
|
pub(super) fn parse_struct_fields(
|
|
&mut self,
|
|
pth: ast::Path,
|
|
recover: bool,
|
|
close_delim: Delimiter,
|
|
) -> PResult<'a, (ThinVec<ExprField>, ast::StructRest, bool)> {
|
|
let mut fields = ThinVec::new();
|
|
let mut base = ast::StructRest::None;
|
|
let mut recover_async = false;
|
|
|
|
let mut async_block_err = |e: &mut Diagnostic, span: Span| {
|
|
recover_async = true;
|
|
errors::AsyncBlockIn2015 { span }.add_to_diagnostic(e);
|
|
errors::HelpUseLatestEdition::new().add_to_diagnostic(e);
|
|
};
|
|
|
|
while self.token != token::CloseDelim(close_delim) {
|
|
if self.eat(&token::DotDot) || self.recover_struct_field_dots(close_delim) {
|
|
let exp_span = self.prev_token.span;
|
|
// We permit `.. }` on the left-hand side of a destructuring assignment.
|
|
if self.check(&token::CloseDelim(close_delim)) {
|
|
base = ast::StructRest::Rest(self.prev_token.span.shrink_to_hi());
|
|
break;
|
|
}
|
|
match self.parse_expr() {
|
|
Ok(e) => base = ast::StructRest::Base(e),
|
|
Err(mut e) if recover => {
|
|
e.emit();
|
|
self.recover_stmt();
|
|
}
|
|
Err(e) => return Err(e),
|
|
}
|
|
self.recover_struct_comma_after_dotdot(exp_span);
|
|
break;
|
|
}
|
|
|
|
let recovery_field = self.find_struct_error_after_field_looking_code();
|
|
let parsed_field = match self.parse_expr_field() {
|
|
Ok(f) => Some(f),
|
|
Err(mut e) => {
|
|
if pth == kw::Async {
|
|
async_block_err(&mut e, pth.span);
|
|
} else {
|
|
e.span_label(pth.span, "while parsing this struct");
|
|
}
|
|
|
|
if !recover {
|
|
return Err(e);
|
|
}
|
|
|
|
e.emit();
|
|
|
|
// If the next token is a comma, then try to parse
|
|
// what comes next as additional fields, rather than
|
|
// bailing out until next `}`.
|
|
if self.token != token::Comma {
|
|
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
|
|
if self.token != token::Comma {
|
|
break;
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
};
|
|
|
|
let is_shorthand = parsed_field.as_ref().map_or(false, |f| f.is_shorthand);
|
|
// A shorthand field can be turned into a full field with `:`.
|
|
// We should point this out.
|
|
self.check_or_expected(!is_shorthand, TokenType::Token(token::Colon));
|
|
|
|
match self.expect_one_of(&[token::Comma], &[token::CloseDelim(close_delim)]) {
|
|
Ok(_) => {
|
|
if let Some(f) = parsed_field.or(recovery_field) {
|
|
// Only include the field if there's no parse error for the field name.
|
|
fields.push(f);
|
|
}
|
|
}
|
|
Err(mut e) => {
|
|
if pth == kw::Async {
|
|
async_block_err(&mut e, pth.span);
|
|
} else {
|
|
e.span_label(pth.span, "while parsing this struct");
|
|
if let Some(f) = recovery_field {
|
|
fields.push(f);
|
|
e.span_suggestion(
|
|
self.prev_token.span.shrink_to_hi(),
|
|
"try adding a comma",
|
|
",",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
} else if is_shorthand
|
|
&& (AssocOp::from_token(&self.token).is_some()
|
|
|| matches!(&self.token.kind, token::OpenDelim(_))
|
|
|| self.token.kind == token::Dot)
|
|
{
|
|
// Looks like they tried to write a shorthand, complex expression.
|
|
let ident = parsed_field.expect("is_shorthand implies Some").ident;
|
|
e.span_suggestion(
|
|
ident.span.shrink_to_lo(),
|
|
"try naming a field",
|
|
&format!("{ident}: "),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
}
|
|
if !recover {
|
|
return Err(e);
|
|
}
|
|
e.emit();
|
|
self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
|
|
self.eat(&token::Comma);
|
|
}
|
|
}
|
|
}
|
|
Ok((fields, base, recover_async))
|
|
}
|
|
|
|
/// Precondition: already parsed the '{'.
|
|
pub(super) fn parse_expr_struct(
|
|
&mut self,
|
|
qself: Option<P<ast::QSelf>>,
|
|
pth: ast::Path,
|
|
recover: bool,
|
|
) -> PResult<'a, P<Expr>> {
|
|
let lo = pth.span;
|
|
let (fields, base, recover_async) =
|
|
self.parse_struct_fields(pth.clone(), recover, Delimiter::Brace)?;
|
|
let span = lo.to(self.token.span);
|
|
self.expect(&token::CloseDelim(Delimiter::Brace))?;
|
|
let expr = if recover_async {
|
|
ExprKind::Err
|
|
} else {
|
|
ExprKind::Struct(P(ast::StructExpr { qself, path: pth, fields, rest: base }))
|
|
};
|
|
Ok(self.mk_expr(span, expr))
|
|
}
|
|
|
|
/// Use in case of error after field-looking code: `S { foo: () with a }`.
|
|
fn find_struct_error_after_field_looking_code(&self) -> Option<ExprField> {
|
|
match self.token.ident() {
|
|
Some((ident, is_raw))
|
|
if (is_raw || !ident.is_reserved())
|
|
&& self.look_ahead(1, |t| *t == token::Colon) =>
|
|
{
|
|
Some(ast::ExprField {
|
|
ident,
|
|
span: self.token.span,
|
|
expr: self.mk_expr_err(self.token.span),
|
|
is_shorthand: false,
|
|
attrs: AttrVec::new(),
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
})
|
|
}
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
fn recover_struct_comma_after_dotdot(&mut self, span: Span) {
|
|
if self.token != token::Comma {
|
|
return;
|
|
}
|
|
self.sess.emit_err(errors::CommaAfterBaseStruct {
|
|
span: span.to(self.prev_token.span),
|
|
comma: self.token.span,
|
|
});
|
|
self.recover_stmt();
|
|
}
|
|
|
|
fn recover_struct_field_dots(&mut self, close_delim: Delimiter) -> bool {
|
|
if !self.look_ahead(1, |t| *t == token::CloseDelim(close_delim))
|
|
&& self.eat(&token::DotDotDot)
|
|
{
|
|
// recover from typo of `...`, suggest `..`
|
|
let span = self.prev_token.span;
|
|
self.sess.emit_err(errors::MissingDotDot { token_span: span, sugg_span: span });
|
|
return true;
|
|
}
|
|
false
|
|
}
|
|
|
|
/// Converts an ident into 'label and emits an "expected a label, found an identifier" error.
|
|
fn recover_ident_into_label(&mut self, ident: Ident) -> Label {
|
|
// Convert `label` -> `'label`,
|
|
// so that nameres doesn't complain about non-existing label
|
|
let label = format!("'{}", ident.name);
|
|
let ident = Ident { name: Symbol::intern(&label), span: ident.span };
|
|
|
|
self.sess.emit_err(errors::ExpectedLabelFoundIdent {
|
|
span: ident.span,
|
|
start: ident.span.shrink_to_lo(),
|
|
});
|
|
|
|
Label { ident }
|
|
}
|
|
|
|
/// Parses `ident (COLON expr)?`.
|
|
fn parse_expr_field(&mut self) -> PResult<'a, ExprField> {
|
|
let attrs = self.parse_outer_attributes()?;
|
|
self.recover_diff_marker();
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let lo = this.token.span;
|
|
|
|
// Check if a colon exists one ahead. This means we're parsing a fieldname.
|
|
let is_shorthand = !this.look_ahead(1, |t| t == &token::Colon || t == &token::Eq);
|
|
let (ident, expr) = if is_shorthand {
|
|
// Mimic `x: x` for the `x` field shorthand.
|
|
let ident = this.parse_ident_common(false)?;
|
|
let path = ast::Path::from_ident(ident);
|
|
(ident, this.mk_expr(ident.span, ExprKind::Path(None, path)))
|
|
} else {
|
|
let ident = this.parse_field_name()?;
|
|
this.error_on_eq_field_init(ident);
|
|
this.bump(); // `:`
|
|
(ident, this.parse_expr()?)
|
|
};
|
|
|
|
Ok((
|
|
ast::ExprField {
|
|
ident,
|
|
span: lo.to(expr.span),
|
|
expr,
|
|
is_shorthand,
|
|
attrs,
|
|
id: DUMMY_NODE_ID,
|
|
is_placeholder: false,
|
|
},
|
|
TrailingToken::MaybeComma,
|
|
))
|
|
})
|
|
}
|
|
|
|
/// Check for `=`. This means the source incorrectly attempts to
|
|
/// initialize a field with an eq rather than a colon.
|
|
fn error_on_eq_field_init(&self, field_name: Ident) {
|
|
if self.token != token::Eq {
|
|
return;
|
|
}
|
|
|
|
self.sess.emit_err(errors::EqFieldInit {
|
|
span: self.token.span,
|
|
eq: field_name.span.shrink_to_hi().to(self.token.span),
|
|
});
|
|
}
|
|
|
|
fn err_dotdotdot_syntax(&self, span: Span) {
|
|
self.sess.emit_err(errors::DotDotDot { span });
|
|
}
|
|
|
|
fn err_larrow_operator(&self, span: Span) {
|
|
self.sess.emit_err(errors::LeftArrowOperator { span });
|
|
}
|
|
|
|
fn mk_assign_op(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
|
|
ExprKind::AssignOp(binop, lhs, rhs)
|
|
}
|
|
|
|
fn mk_range(
|
|
&mut self,
|
|
start: Option<P<Expr>>,
|
|
end: Option<P<Expr>>,
|
|
limits: RangeLimits,
|
|
) -> ExprKind {
|
|
if end.is_none() && limits == RangeLimits::Closed {
|
|
self.inclusive_range_with_incorrect_end();
|
|
ExprKind::Err
|
|
} else {
|
|
ExprKind::Range(start, end, limits)
|
|
}
|
|
}
|
|
|
|
fn mk_unary(&self, unop: UnOp, expr: P<Expr>) -> ExprKind {
|
|
ExprKind::Unary(unop, expr)
|
|
}
|
|
|
|
fn mk_binary(&self, binop: BinOp, lhs: P<Expr>, rhs: P<Expr>) -> ExprKind {
|
|
ExprKind::Binary(binop, lhs, rhs)
|
|
}
|
|
|
|
fn mk_index(&self, expr: P<Expr>, idx: P<Expr>) -> ExprKind {
|
|
ExprKind::Index(expr, idx)
|
|
}
|
|
|
|
fn mk_call(&self, f: P<Expr>, args: ThinVec<P<Expr>>) -> ExprKind {
|
|
ExprKind::Call(f, args)
|
|
}
|
|
|
|
fn mk_await_expr(&mut self, self_arg: P<Expr>, lo: Span) -> P<Expr> {
|
|
let span = lo.to(self.prev_token.span);
|
|
let await_expr = self.mk_expr(span, ExprKind::Await(self_arg, self.prev_token.span));
|
|
self.recover_from_await_method_call();
|
|
await_expr
|
|
}
|
|
|
|
pub(crate) fn mk_expr_with_attrs(&self, span: Span, kind: ExprKind, attrs: AttrVec) -> P<Expr> {
|
|
P(Expr { kind, span, attrs, id: DUMMY_NODE_ID, tokens: None })
|
|
}
|
|
|
|
pub(crate) fn mk_expr(&self, span: Span, kind: ExprKind) -> P<Expr> {
|
|
P(Expr { kind, span, attrs: AttrVec::new(), id: DUMMY_NODE_ID, tokens: None })
|
|
}
|
|
|
|
pub(super) fn mk_expr_err(&self, span: Span) -> P<Expr> {
|
|
self.mk_expr(span, ExprKind::Err)
|
|
}
|
|
|
|
/// Create expression span ensuring the span of the parent node
|
|
/// is larger than the span of lhs and rhs, including the attributes.
|
|
fn mk_expr_sp(&self, lhs: &P<Expr>, lhs_span: Span, rhs_span: Span) -> Span {
|
|
lhs.attrs
|
|
.iter()
|
|
.find(|a| a.style == AttrStyle::Outer)
|
|
.map_or(lhs_span, |a| a.span)
|
|
.to(rhs_span)
|
|
}
|
|
|
|
fn collect_tokens_for_expr(
|
|
&mut self,
|
|
attrs: AttrWrapper,
|
|
f: impl FnOnce(&mut Self, ast::AttrVec) -> PResult<'a, P<Expr>>,
|
|
) -> PResult<'a, P<Expr>> {
|
|
self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
|
|
let res = f(this, attrs)?;
|
|
let trailing = if this.restrictions.contains(Restrictions::STMT_EXPR)
|
|
&& this.token.kind == token::Semi
|
|
{
|
|
TrailingToken::Semi
|
|
} else if this.token.kind == token::Gt {
|
|
TrailingToken::Gt
|
|
} else {
|
|
// FIXME - pass this through from the place where we know
|
|
// we need a comma, rather than assuming that `#[attr] expr,`
|
|
// always captures a trailing comma
|
|
TrailingToken::MaybeComma
|
|
};
|
|
Ok((res, trailing))
|
|
})
|
|
}
|
|
}
|