From fea630ef9d738aabaf6cbf3ccedb1bc1adae1e6d Mon Sep 17 00:00:00 2001 From: Vadim Petrochenkov Date: Wed, 19 Oct 2016 23:33:41 +0300 Subject: [PATCH] Tweak path parsing logic --- src/libsyntax/parse/parser.rs | 38 +++++++++++-------- src/libsyntax/parse/token.rs | 11 ++++-- src/test/compile-fail/associated-path-shl.rs | 20 ++++++++++ .../keyword-self-as-identifier.rs | 4 +- .../keyword-super-as-identifier.rs | 4 +- .../keyword-super.rs | 4 +- .../compile-fail/self-vs-path-ambiguity.rs | 23 +++++++++++ src/test/compile-fail/self_type_keyword-2.rs | 12 +++++- src/test/compile-fail/self_type_keyword.rs | 7 ---- src/test/run-pass/union/union-backcomp.rs | 6 +++ 10 files changed, 93 insertions(+), 36 deletions(-) create mode 100644 src/test/compile-fail/associated-path-shl.rs rename src/test/{parse-fail => compile-fail}/keyword-self-as-identifier.rs (81%) rename src/test/{parse-fail => compile-fail}/keyword-super-as-identifier.rs (81%) rename src/test/{parse-fail => compile-fail}/keyword-super.rs (81%) create mode 100644 src/test/compile-fail/self-vs-path-ambiguity.rs diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index 2509fd12d03..463ec334cc5 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -3620,7 +3620,7 @@ impl<'a> Parser<'a> { // Parse box pat let subpat = self.parse_pat()?; pat = PatKind::Box(subpat); - } else if self.token.is_ident() && self.token.is_path_start() && + } else if self.token.is_ident() && !self.token.is_any_keyword() && self.look_ahead(1, |t| match *t { token::OpenDelim(token::Paren) | token::OpenDelim(token::Brace) | token::DotDotDot | token::ModSep | token::Not => false, @@ -3871,6 +3871,11 @@ impl<'a> Parser<'a> { }) } + fn is_union_item(&mut self) -> bool { + self.token.is_keyword(keywords::Union) && + self.look_ahead(1, |t| t.is_ident() && !t.is_any_keyword()) + } + fn parse_stmt_without_recovery(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option> { @@ -3885,10 +3890,10 @@ impl<'a> Parser<'a> { node: StmtKind::Local(self.parse_local(attrs.into())?), span: mk_sp(lo, self.prev_span.hi), } - } else if self.token.is_path_start() && self.token != token::Lt && { - !self.check_keyword(keywords::Union) || - self.look_ahead(1, |t| *t == token::Not || *t == token::ModSep) - } { + // Starts like a simple path, but not a union item. + } else if self.token.is_path_start() && + !self.token.is_qpath_start() && + !self.is_union_item() { let pth = self.parse_path(PathStyle::Expr)?; if !self.eat(&token::Not) { @@ -4599,6 +4604,10 @@ impl<'a> Parser<'a> { token::Ident(ident) => { this.bump(); codemap::respan(this.prev_span, ident) } _ => unreachable!() }; + let isolated_self = |this: &mut Self, n| { + this.look_ahead(n, |t| t.is_keyword(keywords::SelfValue)) && + this.look_ahead(n + 1, |t| t != &token::ModSep) + }; // Parse optional self parameter of a method. // Only a limited set of initial token sequences is considered self parameters, anything @@ -4611,22 +4620,22 @@ impl<'a> Parser<'a> { // &'lt self // &'lt mut self // ¬_self - if self.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) { + if isolated_self(self, 1) { self.bump(); (SelfKind::Region(None, Mutability::Immutable), expect_ident(self)) } else if self.look_ahead(1, |t| t.is_keyword(keywords::Mut)) && - self.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) { + isolated_self(self, 2) { self.bump(); self.bump(); (SelfKind::Region(None, Mutability::Mutable), expect_ident(self)) } else if self.look_ahead(1, |t| t.is_lifetime()) && - self.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) { + isolated_self(self, 2) { self.bump(); let lt = self.parse_lifetime()?; (SelfKind::Region(Some(lt), Mutability::Immutable), expect_ident(self)) } else if self.look_ahead(1, |t| t.is_lifetime()) && self.look_ahead(2, |t| t.is_keyword(keywords::Mut)) && - self.look_ahead(3, |t| t.is_keyword(keywords::SelfValue)) { + isolated_self(self, 3) { self.bump(); let lt = self.parse_lifetime()?; self.bump(); @@ -4641,12 +4650,12 @@ impl<'a> Parser<'a> { // *mut self // *not_self // Emit special error for `self` cases. - if self.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) { + if isolated_self(self, 1) { self.bump(); self.span_err(self.span, "cannot pass `self` by raw pointer"); (SelfKind::Value(Mutability::Immutable), expect_ident(self)) } else if self.look_ahead(1, |t| t.is_mutability()) && - self.look_ahead(2, |t| t.is_keyword(keywords::SelfValue)) { + isolated_self(self, 2) { self.bump(); self.bump(); self.span_err(self.span, "cannot pass `self` by raw pointer"); @@ -4656,7 +4665,7 @@ impl<'a> Parser<'a> { } } token::Ident(..) => { - if self.token.is_keyword(keywords::SelfValue) { + if isolated_self(self, 0) { // self // self: TYPE let eself_ident = expect_ident(self); @@ -4667,7 +4676,7 @@ impl<'a> Parser<'a> { (SelfKind::Value(Mutability::Immutable), eself_ident) } } else if self.token.is_keyword(keywords::Mut) && - self.look_ahead(1, |t| t.is_keyword(keywords::SelfValue)) { + isolated_self(self, 1) { // mut self // mut self: TYPE self.bump(); @@ -5958,8 +5967,7 @@ impl<'a> Parser<'a> { maybe_append(attrs, extra_attrs)); return Ok(Some(item)); } - if self.check_keyword(keywords::Union) && - self.look_ahead(1, |t| t.is_ident() && !t.is_any_keyword()) { + if self.is_union_item() { // UNION ITEM self.bump(); let (ident, item_, extra_attrs) = self.parse_item_union()?; diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs index 26b5b99c8cc..4d0da660302 100644 --- a/src/libsyntax/parse/token.rs +++ b/src/libsyntax/parse/token.rs @@ -159,10 +159,8 @@ impl Token { /// Returns `true` if the token can appear at the start of an expression. pub fn can_begin_expr(&self) -> bool { match *self { - OpenDelim(_) => true, + OpenDelim(..) => true, Ident(..) => true, - Underscore => true, - Tilde => true, Literal(..) => true, Not => true, BinOp(Minus) => true, @@ -172,6 +170,7 @@ impl Token { OrOr => true, // in lambda syntax AndAnd => true, // double borrow DotDot | DotDotDot => true, // range notation + Lt | BinOp(Shl) => true, // associated path ModSep => true, Interpolated(NtExpr(..)) => true, Interpolated(NtIdent(..)) => true, @@ -236,8 +235,12 @@ impl Token { self.is_keyword(keywords::Const) } + pub fn is_qpath_start(&self) -> bool { + self == &Lt || self == &BinOp(Shl) + } + pub fn is_path_start(&self) -> bool { - self == &ModSep || self == &Lt || self.is_path() || + self == &ModSep || self.is_qpath_start() || self.is_path() || self.is_path_segment_keyword() || self.is_ident() && !self.is_any_keyword() } diff --git a/src/test/compile-fail/associated-path-shl.rs b/src/test/compile-fail/associated-path-shl.rs new file mode 100644 index 00000000000..6bc110239cd --- /dev/null +++ b/src/test/compile-fail/associated-path-shl.rs @@ -0,0 +1,20 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Check that associated paths starting with `<<` are successfully parsed. + +fn main() { + let _: <::B>::C; //~ ERROR type name `A` is undefined or not in scope + let _ = <::B>::C; //~ ERROR type name `A` is undefined or not in scope + let <::B>::C; //~ ERROR type name `A` is undefined or not in scope + let 0 ... <::B>::C; //~ ERROR type name `A` is undefined or not in scope + //~^ ERROR only char and numeric types are allowed in range patterns + <::B>::C; //~ ERROR type name `A` is undefined or not in scope +} diff --git a/src/test/parse-fail/keyword-self-as-identifier.rs b/src/test/compile-fail/keyword-self-as-identifier.rs similarity index 81% rename from src/test/parse-fail/keyword-self-as-identifier.rs rename to src/test/compile-fail/keyword-self-as-identifier.rs index f8b93a1796b..650874711a6 100644 --- a/src/test/parse-fail/keyword-self-as-identifier.rs +++ b/src/test/compile-fail/keyword-self-as-identifier.rs @@ -8,8 +8,6 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -// compile-flags: -Z parse-only - fn main() { - let Self = "foo"; //~ error: expected identifier, found keyword `Self` + let Self = "foo"; //~ ERROR unresolved unit struct/variant or constant `Self` } diff --git a/src/test/parse-fail/keyword-super-as-identifier.rs b/src/test/compile-fail/keyword-super-as-identifier.rs similarity index 81% rename from src/test/parse-fail/keyword-super-as-identifier.rs rename to src/test/compile-fail/keyword-super-as-identifier.rs index a48683a4f54..531705563e2 100644 --- a/src/test/parse-fail/keyword-super-as-identifier.rs +++ b/src/test/compile-fail/keyword-super-as-identifier.rs @@ -8,8 +8,6 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -// compile-flags: -Z parse-only - fn main() { - let super = "foo"; //~ error: expected identifier, found keyword `super` + let super = "foo"; //~ ERROR unresolved unit struct/variant or constant `super` } diff --git a/src/test/parse-fail/keyword-super.rs b/src/test/compile-fail/keyword-super.rs similarity index 81% rename from src/test/parse-fail/keyword-super.rs rename to src/test/compile-fail/keyword-super.rs index 671be8c44b9..9ac9e800c84 100644 --- a/src/test/parse-fail/keyword-super.rs +++ b/src/test/compile-fail/keyword-super.rs @@ -8,8 +8,6 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -// compile-flags: -Z parse-only - fn main() { - let super: isize; //~ ERROR expected identifier, found keyword `super` + let super: isize; //~ ERROR unresolved unit struct/variant or constant `super` } diff --git a/src/test/compile-fail/self-vs-path-ambiguity.rs b/src/test/compile-fail/self-vs-path-ambiguity.rs new file mode 100644 index 00000000000..9753014e781 --- /dev/null +++ b/src/test/compile-fail/self-vs-path-ambiguity.rs @@ -0,0 +1,23 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// Check that `self::foo` is parsed as a general pattern and not a self argument. + +struct S; + +impl S { + fn f(self::S: S) {} + fn g(&self::S: &S) {} + fn h(&mut self::S: &mut S) {} + fn i(&'a self::S: &S) {} //~ ERROR unexpected lifetime `'a` in pattern + //~^ ERROR expected one of `)` or `mut`, found `'a` +} + +fn main() {} diff --git a/src/test/compile-fail/self_type_keyword-2.rs b/src/test/compile-fail/self_type_keyword-2.rs index 613f54eb331..118d3d8a0be 100644 --- a/src/test/compile-fail/self_type_keyword-2.rs +++ b/src/test/compile-fail/self_type_keyword-2.rs @@ -10,4 +10,14 @@ use self::Self as Foo; //~ ERROR unresolved import `self::Self` -pub fn main() {} +pub fn main() { + let Self = 5; + //~^ ERROR unresolved unit struct/variant or constant `Self` + + match 15 { + Self => (), + //~^ ERROR unresolved unit struct/variant or constant `Self` + Foo { x: Self } => (), + //~^ ERROR unresolved unit struct/variant or constant `Self` + } +} diff --git a/src/test/compile-fail/self_type_keyword.rs b/src/test/compile-fail/self_type_keyword.rs index 0f2a3f12107..db6bcc611b8 100644 --- a/src/test/compile-fail/self_type_keyword.rs +++ b/src/test/compile-fail/self_type_keyword.rs @@ -17,12 +17,7 @@ struct Bar<'Self>; //~^ ERROR lifetimes cannot use keyword names pub fn main() { - let Self = 5; - //~^ ERROR expected identifier, found keyword `Self` - match 15 { - Self => (), - //~^ ERROR expected identifier, found keyword `Self` ref Self => (), //~^ ERROR expected identifier, found keyword `Self` mut Self => (), @@ -31,8 +26,6 @@ pub fn main() { //~^ ERROR expected identifier, found keyword `Self` Self!() => (), //~^ ERROR macro undefined: 'Self!' - Foo { x: Self } => (), - //~^ ERROR expected identifier, found keyword `Self` Foo { Self } => (), //~^ ERROR expected identifier, found keyword `Self` } diff --git a/src/test/run-pass/union/union-backcomp.rs b/src/test/run-pass/union/union-backcomp.rs index 9394b618ddf..0f8c996bebd 100644 --- a/src/test/run-pass/union/union-backcomp.rs +++ b/src/test/run-pass/union/union-backcomp.rs @@ -10,6 +10,12 @@ #![feature(untagged_unions)] +macro_rules! union { + () => (struct S;) +} + +union!(); + fn union() {} fn main() {