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https://github.com/rust-lang/rust.git
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Moved the functions starting with check to a separate file
This commit is contained in:
Nicholas-Baron
parent
16d0205d5c
commit
84878794ed
975
compiler/rustc_typeck/src/check/fn_ctxt_checks.rs
Normal file
975
compiler/rustc_typeck/src/check/fn_ctxt_checks.rs
Normal file
@ -0,0 +1,975 @@
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use super::coercion::CoerceMany;
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use super::method::MethodCallee;
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use super::Expectation::*;
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use super::TupleArgumentsFlag::*;
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use super::{
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potentially_plural_count, struct_span_err, BreakableCtxt, Diverges, Expectation, FnCtxt,
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LocalTy, Needs, TupleArgumentsFlag,
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};
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use crate::astconv::AstConv;
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use rustc_ast as ast;
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use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticId};
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, Res};
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use rustc_hir::def_id::DefId;
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use rustc_hir::{ExprKind, Node, QPath};
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use rustc_middle::ty::adjustment::AllowTwoPhase;
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use rustc_middle::ty::fold::TypeFoldable;
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use rustc_middle::ty::{self, Ty};
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use rustc_session::Session;
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use rustc_span::symbol::{sym, Ident};
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use rustc_span::{self, Span};
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use rustc_trait_selection::traits::{self, ObligationCauseCode};
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use std::mem::replace;
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use std::slice;
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impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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pub(super) fn check_casts(&self) {
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let mut deferred_cast_checks = self.deferred_cast_checks.borrow_mut();
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for cast in deferred_cast_checks.drain(..) {
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cast.check(self);
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}
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}
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pub(super) fn check_method_argument_types(
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&self,
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sp: Span,
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expr: &'tcx hir::Expr<'tcx>,
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method: Result<MethodCallee<'tcx>, ()>,
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args_no_rcvr: &'tcx [hir::Expr<'tcx>],
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tuple_arguments: TupleArgumentsFlag,
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expected: Expectation<'tcx>,
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) -> Ty<'tcx> {
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let has_error = match method {
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Ok(method) => method.substs.references_error() || method.sig.references_error(),
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Err(_) => true,
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};
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if has_error {
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let err_inputs = self.err_args(args_no_rcvr.len());
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let err_inputs = match tuple_arguments {
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DontTupleArguments => err_inputs,
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TupleArguments => vec![self.tcx.intern_tup(&err_inputs[..])],
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};
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self.check_argument_types(
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sp,
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expr,
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&err_inputs[..],
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&[],
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args_no_rcvr,
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false,
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tuple_arguments,
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None,
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);
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return self.tcx.ty_error();
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}
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let method = method.unwrap();
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// HACK(eddyb) ignore self in the definition (see above).
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let expected_arg_tys = self.expected_inputs_for_expected_output(
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sp,
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expected,
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method.sig.output(),
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&method.sig.inputs()[1..],
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);
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self.check_argument_types(
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sp,
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expr,
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&method.sig.inputs()[1..],
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&expected_arg_tys[..],
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args_no_rcvr,
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method.sig.c_variadic,
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tuple_arguments,
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self.tcx.hir().span_if_local(method.def_id),
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);
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method.sig.output()
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}
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/// Generic function that factors out common logic from function calls,
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/// method calls and overloaded operators.
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pub(super) fn check_argument_types(
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&self,
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sp: Span,
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expr: &'tcx hir::Expr<'tcx>,
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fn_inputs: &[Ty<'tcx>],
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expected_arg_tys: &[Ty<'tcx>],
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args: &'tcx [hir::Expr<'tcx>],
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c_variadic: bool,
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tuple_arguments: TupleArgumentsFlag,
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def_span: Option<Span>,
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) {
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let tcx = self.tcx;
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// Grab the argument types, supplying fresh type variables
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// if the wrong number of arguments were supplied
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let supplied_arg_count = if tuple_arguments == DontTupleArguments { args.len() } else { 1 };
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// All the input types from the fn signature must outlive the call
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// so as to validate implied bounds.
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for (&fn_input_ty, arg_expr) in fn_inputs.iter().zip(args.iter()) {
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self.register_wf_obligation(fn_input_ty.into(), arg_expr.span, traits::MiscObligation);
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}
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let expected_arg_count = fn_inputs.len();
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let param_count_error = |expected_count: usize,
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arg_count: usize,
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error_code: &str,
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c_variadic: bool,
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sugg_unit: bool| {
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let (span, start_span, args) = match &expr.kind {
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hir::ExprKind::Call(hir::Expr { span, .. }, args) => (*span, *span, &args[..]),
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hir::ExprKind::MethodCall(path_segment, span, args, _) => (
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*span,
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// `sp` doesn't point at the whole `foo.bar()`, only at `bar`.
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path_segment
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.args
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.and_then(|args| args.args.iter().last())
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// Account for `foo.bar::<T>()`.
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.map(|arg| {
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// Skip the closing `>`.
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tcx.sess
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.source_map()
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.next_point(tcx.sess.source_map().next_point(arg.span()))
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})
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.unwrap_or(*span),
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&args[1..], // Skip the receiver.
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),
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k => span_bug!(sp, "checking argument types on a non-call: `{:?}`", k),
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};
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let arg_spans = if args.is_empty() {
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// foo()
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// ^^^-- supplied 0 arguments
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// |
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// expected 2 arguments
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vec![tcx.sess.source_map().next_point(start_span).with_hi(sp.hi())]
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} else {
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// foo(1, 2, 3)
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// ^^^ - - - supplied 3 arguments
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// |
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// expected 2 arguments
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args.iter().map(|arg| arg.span).collect::<Vec<Span>>()
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};
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let mut err = tcx.sess.struct_span_err_with_code(
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span,
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&format!(
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"this function takes {}{} but {} {} supplied",
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if c_variadic { "at least " } else { "" },
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potentially_plural_count(expected_count, "argument"),
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potentially_plural_count(arg_count, "argument"),
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if arg_count == 1 { "was" } else { "were" }
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),
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DiagnosticId::Error(error_code.to_owned()),
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);
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let label = format!("supplied {}", potentially_plural_count(arg_count, "argument"));
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for (i, span) in arg_spans.into_iter().enumerate() {
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err.span_label(
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span,
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if arg_count == 0 || i + 1 == arg_count { &label } else { "" },
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);
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}
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if let Some(def_s) = def_span.map(|sp| tcx.sess.source_map().guess_head_span(sp)) {
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err.span_label(def_s, "defined here");
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}
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if sugg_unit {
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let sugg_span = tcx.sess.source_map().end_point(expr.span);
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// remove closing `)` from the span
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let sugg_span = sugg_span.shrink_to_lo();
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err.span_suggestion(
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sugg_span,
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"expected the unit value `()`; create it with empty parentheses",
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String::from("()"),
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Applicability::MachineApplicable,
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);
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} else {
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err.span_label(
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span,
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format!(
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"expected {}{}",
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if c_variadic { "at least " } else { "" },
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potentially_plural_count(expected_count, "argument")
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),
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);
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}
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err.emit();
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};
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let mut expected_arg_tys = expected_arg_tys.to_vec();
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let formal_tys = if tuple_arguments == TupleArguments {
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let tuple_type = self.structurally_resolved_type(sp, fn_inputs[0]);
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match tuple_type.kind() {
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ty::Tuple(arg_types) if arg_types.len() != args.len() => {
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param_count_error(arg_types.len(), args.len(), "E0057", false, false);
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expected_arg_tys = vec![];
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self.err_args(args.len())
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}
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ty::Tuple(arg_types) => {
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expected_arg_tys = match expected_arg_tys.get(0) {
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Some(&ty) => match ty.kind() {
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ty::Tuple(ref tys) => tys.iter().map(|k| k.expect_ty()).collect(),
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_ => vec![],
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},
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None => vec![],
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};
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arg_types.iter().map(|k| k.expect_ty()).collect()
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}
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_ => {
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struct_span_err!(
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tcx.sess,
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sp,
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E0059,
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"cannot use call notation; the first type parameter \
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for the function trait is neither a tuple nor unit"
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)
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.emit();
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expected_arg_tys = vec![];
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self.err_args(args.len())
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}
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}
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} else if expected_arg_count == supplied_arg_count {
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fn_inputs.to_vec()
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} else if c_variadic {
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if supplied_arg_count >= expected_arg_count {
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fn_inputs.to_vec()
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} else {
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param_count_error(expected_arg_count, supplied_arg_count, "E0060", true, false);
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expected_arg_tys = vec![];
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self.err_args(supplied_arg_count)
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}
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} else {
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// is the missing argument of type `()`?
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let sugg_unit = if expected_arg_tys.len() == 1 && supplied_arg_count == 0 {
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self.resolve_vars_if_possible(&expected_arg_tys[0]).is_unit()
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} else if fn_inputs.len() == 1 && supplied_arg_count == 0 {
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self.resolve_vars_if_possible(&fn_inputs[0]).is_unit()
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} else {
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false
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};
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param_count_error(expected_arg_count, supplied_arg_count, "E0061", false, sugg_unit);
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expected_arg_tys = vec![];
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self.err_args(supplied_arg_count)
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};
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debug!(
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"check_argument_types: formal_tys={:?}",
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formal_tys.iter().map(|t| self.ty_to_string(*t)).collect::<Vec<String>>()
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);
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// If there is no expectation, expect formal_tys.
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let expected_arg_tys =
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if !expected_arg_tys.is_empty() { expected_arg_tys } else { formal_tys.clone() };
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let mut final_arg_types: Vec<(usize, Ty<'_>, Ty<'_>)> = vec![];
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// Check the arguments.
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// We do this in a pretty awful way: first we type-check any arguments
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// that are not closures, then we type-check the closures. This is so
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// that we have more information about the types of arguments when we
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// type-check the functions. This isn't really the right way to do this.
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for &check_closures in &[false, true] {
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debug!("check_closures={}", check_closures);
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// More awful hacks: before we check argument types, try to do
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// an "opportunistic" trait resolution of any trait bounds on
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// the call. This helps coercions.
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if check_closures {
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self.select_obligations_where_possible(false, |errors| {
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self.point_at_type_arg_instead_of_call_if_possible(errors, expr);
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self.point_at_arg_instead_of_call_if_possible(
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errors,
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&final_arg_types[..],
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sp,
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&args,
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);
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})
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}
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// For C-variadic functions, we don't have a declared type for all of
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// the arguments hence we only do our usual type checking with
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// the arguments who's types we do know.
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let t = if c_variadic {
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expected_arg_count
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} else if tuple_arguments == TupleArguments {
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args.len()
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} else {
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supplied_arg_count
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};
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for (i, arg) in args.iter().take(t).enumerate() {
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// Warn only for the first loop (the "no closures" one).
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// Closure arguments themselves can't be diverging, but
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// a previous argument can, e.g., `foo(panic!(), || {})`.
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if !check_closures {
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self.warn_if_unreachable(arg.hir_id, arg.span, "expression");
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}
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let is_closure = match arg.kind {
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ExprKind::Closure(..) => true,
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_ => false,
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};
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if is_closure != check_closures {
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continue;
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}
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debug!("checking the argument");
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let formal_ty = formal_tys[i];
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// The special-cased logic below has three functions:
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// 1. Provide as good of an expected type as possible.
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let expected = Expectation::rvalue_hint(self, expected_arg_tys[i]);
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let checked_ty = self.check_expr_with_expectation(&arg, expected);
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// 2. Coerce to the most detailed type that could be coerced
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// to, which is `expected_ty` if `rvalue_hint` returns an
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// `ExpectHasType(expected_ty)`, or the `formal_ty` otherwise.
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let coerce_ty = expected.only_has_type(self).unwrap_or(formal_ty);
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// We're processing function arguments so we definitely want to use
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// two-phase borrows.
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self.demand_coerce(&arg, checked_ty, coerce_ty, None, AllowTwoPhase::Yes);
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final_arg_types.push((i, checked_ty, coerce_ty));
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// 3. Relate the expected type and the formal one,
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// if the expected type was used for the coercion.
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self.demand_suptype(arg.span, formal_ty, coerce_ty);
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}
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}
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// We also need to make sure we at least write the ty of the other
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// arguments which we skipped above.
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if c_variadic {
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fn variadic_error<'tcx>(s: &Session, span: Span, t: Ty<'tcx>, cast_ty: &str) {
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use crate::structured_errors::{StructuredDiagnostic, VariadicError};
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VariadicError::new(s, span, t, cast_ty).diagnostic().emit();
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}
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for arg in args.iter().skip(expected_arg_count) {
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let arg_ty = self.check_expr(&arg);
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// There are a few types which get autopromoted when passed via varargs
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// in C but we just error out instead and require explicit casts.
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let arg_ty = self.structurally_resolved_type(arg.span, arg_ty);
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match arg_ty.kind() {
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ty::Float(ast::FloatTy::F32) => {
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variadic_error(tcx.sess, arg.span, arg_ty, "c_double");
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}
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ty::Int(ast::IntTy::I8 | ast::IntTy::I16) | ty::Bool => {
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variadic_error(tcx.sess, arg.span, arg_ty, "c_int");
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}
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ty::Uint(ast::UintTy::U8 | ast::UintTy::U16) => {
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variadic_error(tcx.sess, arg.span, arg_ty, "c_uint");
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}
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ty::FnDef(..) => {
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let ptr_ty = self.tcx.mk_fn_ptr(arg_ty.fn_sig(self.tcx));
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let ptr_ty = self.resolve_vars_if_possible(&ptr_ty);
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variadic_error(tcx.sess, arg.span, arg_ty, &ptr_ty.to_string());
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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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|
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// AST fragment checking
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pub(super) fn check_lit(&self, lit: &hir::Lit, expected: Expectation<'tcx>) -> Ty<'tcx> {
|
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let tcx = self.tcx;
|
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|
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match lit.node {
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ast::LitKind::Str(..) => tcx.mk_static_str(),
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ast::LitKind::ByteStr(ref v) => {
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tcx.mk_imm_ref(tcx.lifetimes.re_static, tcx.mk_array(tcx.types.u8, v.len() as u64))
|
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}
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ast::LitKind::Byte(_) => tcx.types.u8,
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ast::LitKind::Char(_) => tcx.types.char,
|
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ast::LitKind::Int(_, ast::LitIntType::Signed(t)) => tcx.mk_mach_int(t),
|
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ast::LitKind::Int(_, ast::LitIntType::Unsigned(t)) => tcx.mk_mach_uint(t),
|
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ast::LitKind::Int(_, ast::LitIntType::Unsuffixed) => {
|
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let opt_ty = expected.to_option(self).and_then(|ty| match ty.kind() {
|
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ty::Int(_) | ty::Uint(_) => Some(ty),
|
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ty::Char => Some(tcx.types.u8),
|
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ty::RawPtr(..) => Some(tcx.types.usize),
|
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ty::FnDef(..) | ty::FnPtr(_) => Some(tcx.types.usize),
|
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_ => None,
|
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});
|
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opt_ty.unwrap_or_else(|| self.next_int_var())
|
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}
|
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ast::LitKind::Float(_, ast::LitFloatType::Suffixed(t)) => tcx.mk_mach_float(t),
|
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ast::LitKind::Float(_, ast::LitFloatType::Unsuffixed) => {
|
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let opt_ty = expected.to_option(self).and_then(|ty| match ty.kind() {
|
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ty::Float(_) => Some(ty),
|
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_ => None,
|
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});
|
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opt_ty.unwrap_or_else(|| self.next_float_var())
|
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}
|
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ast::LitKind::Bool(_) => tcx.types.bool,
|
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ast::LitKind::Err(_) => tcx.ty_error(),
|
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}
|
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}
|
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|
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pub fn check_struct_path(
|
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&self,
|
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qpath: &QPath<'_>,
|
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hir_id: hir::HirId,
|
||||
) -> Option<(&'tcx ty::VariantDef, Ty<'tcx>)> {
|
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let path_span = qpath.qself_span();
|
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let (def, ty) = self.finish_resolving_struct_path(qpath, path_span, hir_id);
|
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let variant = match def {
|
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Res::Err => {
|
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self.set_tainted_by_errors();
|
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return None;
|
||||
}
|
||||
Res::Def(DefKind::Variant, _) => match ty.kind() {
|
||||
ty::Adt(adt, substs) => Some((adt.variant_of_res(def), adt.did, substs)),
|
||||
_ => bug!("unexpected type: {:?}", ty),
|
||||
},
|
||||
Res::Def(DefKind::Struct | DefKind::Union | DefKind::TyAlias | DefKind::AssocTy, _)
|
||||
| Res::SelfTy(..) => match ty.kind() {
|
||||
ty::Adt(adt, substs) if !adt.is_enum() => {
|
||||
Some((adt.non_enum_variant(), adt.did, substs))
|
||||
}
|
||||
_ => None,
|
||||
},
|
||||
_ => bug!("unexpected definition: {:?}", def),
|
||||
};
|
||||
|
||||
if let Some((variant, did, substs)) = variant {
|
||||
debug!("check_struct_path: did={:?} substs={:?}", did, substs);
|
||||
self.write_user_type_annotation_from_substs(hir_id, did, substs, None);
|
||||
|
||||
// Check bounds on type arguments used in the path.
|
||||
let (bounds, _) = self.instantiate_bounds(path_span, did, substs);
|
||||
let cause =
|
||||
traits::ObligationCause::new(path_span, self.body_id, traits::ItemObligation(did));
|
||||
self.add_obligations_for_parameters(cause, bounds);
|
||||
|
||||
Some((variant, ty))
|
||||
} else {
|
||||
struct_span_err!(
|
||||
self.tcx.sess,
|
||||
path_span,
|
||||
E0071,
|
||||
"expected struct, variant or union type, found {}",
|
||||
ty.sort_string(self.tcx)
|
||||
)
|
||||
.span_label(path_span, "not a struct")
|
||||
.emit();
|
||||
None
|
||||
}
|
||||
}
|
||||
|
||||
pub fn check_decl_initializer(
|
||||
&self,
|
||||
local: &'tcx hir::Local<'tcx>,
|
||||
init: &'tcx hir::Expr<'tcx>,
|
||||
) -> Ty<'tcx> {
|
||||
// FIXME(tschottdorf): `contains_explicit_ref_binding()` must be removed
|
||||
// for #42640 (default match binding modes).
|
||||
//
|
||||
// See #44848.
|
||||
let ref_bindings = local.pat.contains_explicit_ref_binding();
|
||||
|
||||
let local_ty = self.local_ty(init.span, local.hir_id).revealed_ty;
|
||||
if let Some(m) = ref_bindings {
|
||||
// Somewhat subtle: if we have a `ref` binding in the pattern,
|
||||
// we want to avoid introducing coercions for the RHS. This is
|
||||
// both because it helps preserve sanity and, in the case of
|
||||
// ref mut, for soundness (issue #23116). In particular, in
|
||||
// the latter case, we need to be clear that the type of the
|
||||
// referent for the reference that results is *equal to* the
|
||||
// type of the place it is referencing, and not some
|
||||
// supertype thereof.
|
||||
let init_ty = self.check_expr_with_needs(init, Needs::maybe_mut_place(m));
|
||||
self.demand_eqtype(init.span, local_ty, init_ty);
|
||||
init_ty
|
||||
} else {
|
||||
self.check_expr_coercable_to_type(init, local_ty, None)
|
||||
}
|
||||
}
|
||||
|
||||
/// Type check a `let` statement.
|
||||
pub fn check_decl_local(&self, local: &'tcx hir::Local<'tcx>) {
|
||||
// Determine and write the type which we'll check the pattern against.
|
||||
let ty = self.local_ty(local.span, local.hir_id).decl_ty;
|
||||
self.write_ty(local.hir_id, ty);
|
||||
|
||||
// Type check the initializer.
|
||||
if let Some(ref init) = local.init {
|
||||
let init_ty = self.check_decl_initializer(local, &init);
|
||||
self.overwrite_local_ty_if_err(local, ty, init_ty);
|
||||
}
|
||||
|
||||
// Does the expected pattern type originate from an expression and what is the span?
|
||||
let (origin_expr, ty_span) = match (local.ty, local.init) {
|
||||
(Some(ty), _) => (false, Some(ty.span)), // Bias towards the explicit user type.
|
||||
(_, Some(init)) => (true, Some(init.span)), // No explicit type; so use the scrutinee.
|
||||
_ => (false, None), // We have `let $pat;`, so the expected type is unconstrained.
|
||||
};
|
||||
|
||||
// Type check the pattern. Override if necessary to avoid knock-on errors.
|
||||
self.check_pat_top(&local.pat, ty, ty_span, origin_expr);
|
||||
let pat_ty = self.node_ty(local.pat.hir_id);
|
||||
self.overwrite_local_ty_if_err(local, ty, pat_ty);
|
||||
}
|
||||
|
||||
pub fn check_stmt(&self, stmt: &'tcx hir::Stmt<'tcx>) {
|
||||
// Don't do all the complex logic below for `DeclItem`.
|
||||
match stmt.kind {
|
||||
hir::StmtKind::Item(..) => return,
|
||||
hir::StmtKind::Local(..) | hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => {}
|
||||
}
|
||||
|
||||
self.warn_if_unreachable(stmt.hir_id, stmt.span, "statement");
|
||||
|
||||
// Hide the outer diverging and `has_errors` flags.
|
||||
let old_diverges = self.diverges.replace(Diverges::Maybe);
|
||||
let old_has_errors = self.has_errors.replace(false);
|
||||
|
||||
match stmt.kind {
|
||||
hir::StmtKind::Local(ref l) => {
|
||||
self.check_decl_local(&l);
|
||||
}
|
||||
// Ignore for now.
|
||||
hir::StmtKind::Item(_) => {}
|
||||
hir::StmtKind::Expr(ref expr) => {
|
||||
// Check with expected type of `()`.
|
||||
self.check_expr_has_type_or_error(&expr, self.tcx.mk_unit(), |err| {
|
||||
self.suggest_semicolon_at_end(expr.span, err);
|
||||
});
|
||||
}
|
||||
hir::StmtKind::Semi(ref expr) => {
|
||||
self.check_expr(&expr);
|
||||
}
|
||||
}
|
||||
|
||||
// Combine the diverging and `has_error` flags.
|
||||
self.diverges.set(self.diverges.get() | old_diverges);
|
||||
self.has_errors.set(self.has_errors.get() | old_has_errors);
|
||||
}
|
||||
|
||||
pub fn check_block_no_value(&self, blk: &'tcx hir::Block<'tcx>) {
|
||||
let unit = self.tcx.mk_unit();
|
||||
let ty = self.check_block_with_expected(blk, ExpectHasType(unit));
|
||||
|
||||
// if the block produces a `!` value, that can always be
|
||||
// (effectively) coerced to unit.
|
||||
if !ty.is_never() {
|
||||
self.demand_suptype(blk.span, unit, ty);
|
||||
}
|
||||
}
|
||||
|
||||
pub(super) fn check_block_with_expected(
|
||||
&self,
|
||||
blk: &'tcx hir::Block<'tcx>,
|
||||
expected: Expectation<'tcx>,
|
||||
) -> Ty<'tcx> {
|
||||
let prev = {
|
||||
let mut fcx_ps = self.ps.borrow_mut();
|
||||
let unsafety_state = fcx_ps.recurse(blk);
|
||||
replace(&mut *fcx_ps, unsafety_state)
|
||||
};
|
||||
|
||||
// In some cases, blocks have just one exit, but other blocks
|
||||
// can be targeted by multiple breaks. This can happen both
|
||||
// with labeled blocks as well as when we desugar
|
||||
// a `try { ... }` expression.
|
||||
//
|
||||
// Example 1:
|
||||
//
|
||||
// 'a: { if true { break 'a Err(()); } Ok(()) }
|
||||
//
|
||||
// Here we would wind up with two coercions, one from
|
||||
// `Err(())` and the other from the tail expression
|
||||
// `Ok(())`. If the tail expression is omitted, that's a
|
||||
// "forced unit" -- unless the block diverges, in which
|
||||
// case we can ignore the tail expression (e.g., `'a: {
|
||||
// break 'a 22; }` would not force the type of the block
|
||||
// to be `()`).
|
||||
let tail_expr = blk.expr.as_ref();
|
||||
let coerce_to_ty = expected.coercion_target_type(self, blk.span);
|
||||
let coerce = if blk.targeted_by_break {
|
||||
CoerceMany::new(coerce_to_ty)
|
||||
} else {
|
||||
let tail_expr: &[&hir::Expr<'_>] = match tail_expr {
|
||||
Some(e) => slice::from_ref(e),
|
||||
None => &[],
|
||||
};
|
||||
CoerceMany::with_coercion_sites(coerce_to_ty, tail_expr)
|
||||
};
|
||||
|
||||
let prev_diverges = self.diverges.get();
|
||||
let ctxt = BreakableCtxt { coerce: Some(coerce), may_break: false };
|
||||
|
||||
let (ctxt, ()) = self.with_breakable_ctxt(blk.hir_id, ctxt, || {
|
||||
for s in blk.stmts {
|
||||
self.check_stmt(s);
|
||||
}
|
||||
|
||||
// check the tail expression **without** holding the
|
||||
// `enclosing_breakables` lock below.
|
||||
let tail_expr_ty = tail_expr.map(|t| self.check_expr_with_expectation(t, expected));
|
||||
|
||||
let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
|
||||
let ctxt = enclosing_breakables.find_breakable(blk.hir_id);
|
||||
let coerce = ctxt.coerce.as_mut().unwrap();
|
||||
if let Some(tail_expr_ty) = tail_expr_ty {
|
||||
let tail_expr = tail_expr.unwrap();
|
||||
let span = self.get_expr_coercion_span(tail_expr);
|
||||
let cause = self.cause(span, ObligationCauseCode::BlockTailExpression(blk.hir_id));
|
||||
coerce.coerce(self, &cause, tail_expr, tail_expr_ty);
|
||||
} else {
|
||||
// Subtle: if there is no explicit tail expression,
|
||||
// that is typically equivalent to a tail expression
|
||||
// of `()` -- except if the block diverges. In that
|
||||
// case, there is no value supplied from the tail
|
||||
// expression (assuming there are no other breaks,
|
||||
// this implies that the type of the block will be
|
||||
// `!`).
|
||||
//
|
||||
// #41425 -- label the implicit `()` as being the
|
||||
// "found type" here, rather than the "expected type".
|
||||
if !self.diverges.get().is_always() {
|
||||
// #50009 -- Do not point at the entire fn block span, point at the return type
|
||||
// span, as it is the cause of the requirement, and
|
||||
// `consider_hint_about_removing_semicolon` will point at the last expression
|
||||
// if it were a relevant part of the error. This improves usability in editors
|
||||
// that highlight errors inline.
|
||||
let mut sp = blk.span;
|
||||
let mut fn_span = None;
|
||||
if let Some((decl, ident)) = self.get_parent_fn_decl(blk.hir_id) {
|
||||
let ret_sp = decl.output.span();
|
||||
if let Some(block_sp) = self.parent_item_span(blk.hir_id) {
|
||||
// HACK: on some cases (`ui/liveness/liveness-issue-2163.rs`) the
|
||||
// output would otherwise be incorrect and even misleading. Make sure
|
||||
// the span we're aiming at correspond to a `fn` body.
|
||||
if block_sp == blk.span {
|
||||
sp = ret_sp;
|
||||
fn_span = Some(ident.span);
|
||||
}
|
||||
}
|
||||
}
|
||||
coerce.coerce_forced_unit(
|
||||
self,
|
||||
&self.misc(sp),
|
||||
&mut |err| {
|
||||
if let Some(expected_ty) = expected.only_has_type(self) {
|
||||
self.consider_hint_about_removing_semicolon(blk, expected_ty, err);
|
||||
}
|
||||
if let Some(fn_span) = fn_span {
|
||||
err.span_label(
|
||||
fn_span,
|
||||
"implicitly returns `()` as its body has no tail or `return` \
|
||||
expression",
|
||||
);
|
||||
}
|
||||
},
|
||||
false,
|
||||
);
|
||||
}
|
||||
}
|
||||
});
|
||||
|
||||
if ctxt.may_break {
|
||||
// If we can break from the block, then the block's exit is always reachable
|
||||
// (... as long as the entry is reachable) - regardless of the tail of the block.
|
||||
self.diverges.set(prev_diverges);
|
||||
}
|
||||
|
||||
let mut ty = ctxt.coerce.unwrap().complete(self);
|
||||
|
||||
if self.has_errors.get() || ty.references_error() {
|
||||
ty = self.tcx.ty_error()
|
||||
}
|
||||
|
||||
self.write_ty(blk.hir_id, ty);
|
||||
|
||||
*self.ps.borrow_mut() = prev;
|
||||
ty
|
||||
}
|
||||
|
||||
pub(super) fn check_rustc_args_require_const(
|
||||
&self,
|
||||
def_id: DefId,
|
||||
hir_id: hir::HirId,
|
||||
span: Span,
|
||||
) {
|
||||
// We're only interested in functions tagged with
|
||||
// #[rustc_args_required_const], so ignore anything that's not.
|
||||
if !self.tcx.has_attr(def_id, sym::rustc_args_required_const) {
|
||||
return;
|
||||
}
|
||||
|
||||
// If our calling expression is indeed the function itself, we're good!
|
||||
// If not, generate an error that this can only be called directly.
|
||||
if let Node::Expr(expr) = self.tcx.hir().get(self.tcx.hir().get_parent_node(hir_id)) {
|
||||
if let ExprKind::Call(ref callee, ..) = expr.kind {
|
||||
if callee.hir_id == hir_id {
|
||||
return;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
self.tcx.sess.span_err(
|
||||
span,
|
||||
"this function can only be invoked directly, not through a function pointer",
|
||||
);
|
||||
}
|
||||
|
||||
/// A common error is to add an extra semicolon:
|
||||
///
|
||||
/// ```
|
||||
/// fn foo() -> usize {
|
||||
/// 22;
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// This routine checks if the final statement in a block is an
|
||||
/// expression with an explicit semicolon whose type is compatible
|
||||
/// with `expected_ty`. If so, it suggests removing the semicolon.
|
||||
fn consider_hint_about_removing_semicolon(
|
||||
&self,
|
||||
blk: &'tcx hir::Block<'tcx>,
|
||||
expected_ty: Ty<'tcx>,
|
||||
err: &mut DiagnosticBuilder<'_>,
|
||||
) {
|
||||
if let Some(span_semi) = self.could_remove_semicolon(blk, expected_ty) {
|
||||
err.span_suggestion(
|
||||
span_semi,
|
||||
"consider removing this semicolon",
|
||||
String::new(),
|
||||
Applicability::MachineApplicable,
|
||||
);
|
||||
}
|
||||
}
|
||||
|
||||
fn parent_item_span(&self, id: hir::HirId) -> Option<Span> {
|
||||
let node = self.tcx.hir().get(self.tcx.hir().get_parent_item(id));
|
||||
match node {
|
||||
Node::Item(&hir::Item { kind: hir::ItemKind::Fn(_, _, body_id), .. })
|
||||
| Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Fn(_, body_id), .. }) => {
|
||||
let body = self.tcx.hir().body(body_id);
|
||||
if let ExprKind::Block(block, _) = &body.value.kind {
|
||||
return Some(block.span);
|
||||
}
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
None
|
||||
}
|
||||
|
||||
/// Given a function block's `HirId`, returns its `FnDecl` if it exists, or `None` otherwise.
|
||||
fn get_parent_fn_decl(&self, blk_id: hir::HirId) -> Option<(&'tcx hir::FnDecl<'tcx>, Ident)> {
|
||||
let parent = self.tcx.hir().get(self.tcx.hir().get_parent_item(blk_id));
|
||||
self.get_node_fn_decl(parent).map(|(fn_decl, ident, _)| (fn_decl, ident))
|
||||
}
|
||||
|
||||
/// If `expr` is a `match` expression that has only one non-`!` arm, use that arm's tail
|
||||
/// expression's `Span`, otherwise return `expr.span`. This is done to give better errors
|
||||
/// when given code like the following:
|
||||
/// ```text
|
||||
/// if false { return 0i32; } else { 1u32 }
|
||||
/// // ^^^^ point at this instead of the whole `if` expression
|
||||
/// ```
|
||||
fn get_expr_coercion_span(&self, expr: &hir::Expr<'_>) -> rustc_span::Span {
|
||||
if let hir::ExprKind::Match(_, arms, _) = &expr.kind {
|
||||
let arm_spans: Vec<Span> = arms
|
||||
.iter()
|
||||
.filter_map(|arm| {
|
||||
self.in_progress_typeck_results
|
||||
.and_then(|typeck_results| {
|
||||
typeck_results.borrow().node_type_opt(arm.body.hir_id)
|
||||
})
|
||||
.and_then(|arm_ty| {
|
||||
if arm_ty.is_never() {
|
||||
None
|
||||
} else {
|
||||
Some(match &arm.body.kind {
|
||||
// Point at the tail expression when possible.
|
||||
hir::ExprKind::Block(block, _) => {
|
||||
block.expr.as_ref().map(|e| e.span).unwrap_or(block.span)
|
||||
}
|
||||
_ => arm.body.span,
|
||||
})
|
||||
}
|
||||
})
|
||||
})
|
||||
.collect();
|
||||
if arm_spans.len() == 1 {
|
||||
return arm_spans[0];
|
||||
}
|
||||
}
|
||||
expr.span
|
||||
}
|
||||
|
||||
fn overwrite_local_ty_if_err(
|
||||
&self,
|
||||
local: &'tcx hir::Local<'tcx>,
|
||||
decl_ty: Ty<'tcx>,
|
||||
ty: Ty<'tcx>,
|
||||
) {
|
||||
if ty.references_error() {
|
||||
// Override the types everywhere with `err()` to avoid knock on errors.
|
||||
self.write_ty(local.hir_id, ty);
|
||||
self.write_ty(local.pat.hir_id, ty);
|
||||
let local_ty = LocalTy { decl_ty, revealed_ty: ty };
|
||||
self.locals.borrow_mut().insert(local.hir_id, local_ty);
|
||||
self.locals.borrow_mut().insert(local.pat.hir_id, local_ty);
|
||||
}
|
||||
}
|
||||
|
||||
// Finish resolving a path in a struct expression or pattern `S::A { .. }` if necessary.
|
||||
// The newly resolved definition is written into `type_dependent_defs`.
|
||||
fn finish_resolving_struct_path(
|
||||
&self,
|
||||
qpath: &QPath<'_>,
|
||||
path_span: Span,
|
||||
hir_id: hir::HirId,
|
||||
) -> (Res, Ty<'tcx>) {
|
||||
match *qpath {
|
||||
QPath::Resolved(ref maybe_qself, ref path) => {
|
||||
let self_ty = maybe_qself.as_ref().map(|qself| self.to_ty(qself));
|
||||
let ty = AstConv::res_to_ty(self, self_ty, path, true);
|
||||
(path.res, ty)
|
||||
}
|
||||
QPath::TypeRelative(ref qself, ref segment) => {
|
||||
let ty = self.to_ty(qself);
|
||||
|
||||
let res = if let hir::TyKind::Path(QPath::Resolved(_, ref path)) = qself.kind {
|
||||
path.res
|
||||
} else {
|
||||
Res::Err
|
||||
};
|
||||
let result =
|
||||
AstConv::associated_path_to_ty(self, hir_id, path_span, ty, res, segment, true);
|
||||
let ty = result.map(|(ty, _, _)| ty).unwrap_or_else(|_| self.tcx().ty_error());
|
||||
let result = result.map(|(_, kind, def_id)| (kind, def_id));
|
||||
|
||||
// Write back the new resolution.
|
||||
self.write_resolution(hir_id, result);
|
||||
|
||||
(result.map(|(kind, def_id)| Res::Def(kind, def_id)).unwrap_or(Res::Err), ty)
|
||||
}
|
||||
QPath::LangItem(lang_item, span) => {
|
||||
self.resolve_lang_item_path(lang_item, span, hir_id)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Given a vec of evaluated `FulfillmentError`s and an `fn` call argument expressions, we walk
|
||||
/// the checked and coerced types for each argument to see if any of the `FulfillmentError`s
|
||||
/// reference a type argument. The reason to walk also the checked type is that the coerced type
|
||||
/// can be not easily comparable with predicate type (because of coercion). If the types match
|
||||
/// for either checked or coerced type, and there's only *one* argument that does, we point at
|
||||
/// the corresponding argument's expression span instead of the `fn` call path span.
|
||||
fn point_at_arg_instead_of_call_if_possible(
|
||||
&self,
|
||||
errors: &mut Vec<traits::FulfillmentError<'tcx>>,
|
||||
final_arg_types: &[(usize, Ty<'tcx>, Ty<'tcx>)],
|
||||
call_sp: Span,
|
||||
args: &'tcx [hir::Expr<'tcx>],
|
||||
) {
|
||||
// We *do not* do this for desugared call spans to keep good diagnostics when involving
|
||||
// the `?` operator.
|
||||
if call_sp.desugaring_kind().is_some() {
|
||||
return;
|
||||
}
|
||||
|
||||
for error in errors {
|
||||
// Only if the cause is somewhere inside the expression we want try to point at arg.
|
||||
// Otherwise, it means that the cause is somewhere else and we should not change
|
||||
// anything because we can break the correct span.
|
||||
if !call_sp.contains(error.obligation.cause.span) {
|
||||
continue;
|
||||
}
|
||||
|
||||
if let ty::PredicateAtom::Trait(predicate, _) =
|
||||
error.obligation.predicate.skip_binders()
|
||||
{
|
||||
// Collect the argument position for all arguments that could have caused this
|
||||
// `FulfillmentError`.
|
||||
let mut referenced_in = final_arg_types
|
||||
.iter()
|
||||
.map(|&(i, checked_ty, _)| (i, checked_ty))
|
||||
.chain(final_arg_types.iter().map(|&(i, _, coerced_ty)| (i, coerced_ty)))
|
||||
.flat_map(|(i, ty)| {
|
||||
let ty = self.resolve_vars_if_possible(&ty);
|
||||
// We walk the argument type because the argument's type could have
|
||||
// been `Option<T>`, but the `FulfillmentError` references `T`.
|
||||
if ty.walk().any(|arg| arg == predicate.self_ty().into()) {
|
||||
Some(i)
|
||||
} else {
|
||||
None
|
||||
}
|
||||
})
|
||||
.collect::<Vec<usize>>();
|
||||
|
||||
// Both checked and coerced types could have matched, thus we need to remove
|
||||
// duplicates.
|
||||
|
||||
// We sort primitive type usize here and can use unstable sort
|
||||
referenced_in.sort_unstable();
|
||||
referenced_in.dedup();
|
||||
|
||||
if let (Some(ref_in), None) = (referenced_in.pop(), referenced_in.pop()) {
|
||||
// We make sure that only *one* argument matches the obligation failure
|
||||
// and we assign the obligation's span to its expression's.
|
||||
error.obligation.cause.make_mut().span = args[ref_in].span;
|
||||
error.points_at_arg_span = true;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Given a vec of evaluated `FulfillmentError`s and an `fn` call expression, we walk the
|
||||
/// `PathSegment`s and resolve their type parameters to see if any of the `FulfillmentError`s
|
||||
/// were caused by them. If they were, we point at the corresponding type argument's span
|
||||
/// instead of the `fn` call path span.
|
||||
fn point_at_type_arg_instead_of_call_if_possible(
|
||||
&self,
|
||||
errors: &mut Vec<traits::FulfillmentError<'tcx>>,
|
||||
call_expr: &'tcx hir::Expr<'tcx>,
|
||||
) {
|
||||
if let hir::ExprKind::Call(path, _) = &call_expr.kind {
|
||||
if let hir::ExprKind::Path(qpath) = &path.kind {
|
||||
if let hir::QPath::Resolved(_, path) = &qpath {
|
||||
for error in errors {
|
||||
if let ty::PredicateAtom::Trait(predicate, _) =
|
||||
error.obligation.predicate.skip_binders()
|
||||
{
|
||||
// If any of the type arguments in this path segment caused the
|
||||
// `FullfillmentError`, point at its span (#61860).
|
||||
for arg in path
|
||||
.segments
|
||||
.iter()
|
||||
.filter_map(|seg| seg.args.as_ref())
|
||||
.flat_map(|a| a.args.iter())
|
||||
{
|
||||
if let hir::GenericArg::Type(hir_ty) = &arg {
|
||||
if let hir::TyKind::Path(hir::QPath::TypeRelative(..)) =
|
||||
&hir_ty.kind
|
||||
{
|
||||
// Avoid ICE with associated types. As this is best
|
||||
// effort only, it's ok to ignore the case. It
|
||||
// would trigger in `is_send::<T::AssocType>();`
|
||||
// from `typeck-default-trait-impl-assoc-type.rs`.
|
||||
} else {
|
||||
let ty = AstConv::ast_ty_to_ty(self, hir_ty);
|
||||
let ty = self.resolve_vars_if_possible(&ty);
|
||||
if ty == predicate.self_ty() {
|
||||
error.obligation.cause.make_mut().span = hir_ty.span;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
File diff suppressed because it is too large
Load Diff
@ -76,6 +76,7 @@ pub mod dropck;
|
||||
mod expectation;
|
||||
mod expr;
|
||||
mod fn_ctxt;
|
||||
mod fn_ctxt_checks;
|
||||
mod fn_ctxt_impl;
|
||||
mod fn_ctxt_suggestions;
|
||||
mod gather_locals;
|
||||
@ -99,6 +100,7 @@ pub use check::{check_item_type, check_wf_new};
|
||||
pub use diverges::Diverges;
|
||||
pub use expectation::Expectation;
|
||||
pub use fn_ctxt::FnCtxt;
|
||||
pub use fn_ctxt_checks::*;
|
||||
pub use fn_ctxt_impl::*;
|
||||
pub use fn_ctxt_suggestions::*;
|
||||
pub use inherited::{Inherited, InheritedBuilder};
|
||||
|
||||
Loading…
Reference in New Issue
Block a user