From 2af92bbf2ec353cd5eafb3bd5cb1ea5c1de448d3 Mon Sep 17 00:00:00 2001 From: Obei Sideg Date: Wed, 3 Aug 2022 18:43:29 +0300 Subject: [PATCH 1/3] Suggest removing `let` if `const let` is used --- compiler/rustc_parse/src/parser/item.rs | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index 2c1e5807aa7f9..1d92213be3452 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -1124,6 +1124,16 @@ impl<'a> Parser<'a> { Applicability::MaybeIncorrect, ) .emit(); + } else if self.eat_keyword(kw::Let) { + let span = self.prev_token.span; + self.struct_span_err(const_span.to(span), "`const` and `let` are mutually exclusive") + .span_suggestion( + const_span.to(span), + "remove `let`", + "const", + Applicability::MaybeIncorrect, + ) + .emit(); } } From accb8e34c599f005eaeed010fe7ddbd47760468b Mon Sep 17 00:00:00 2001 From: Obei Sideg Date: Wed, 3 Aug 2022 18:45:26 +0300 Subject: [PATCH 2/3] Suggest removing `let` if `let const` is used --- compiler/rustc_parse/src/parser/stmt.rs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs index 51bd9d2d386ad..6990d0782b772 100644 --- a/compiler/rustc_parse/src/parser/stmt.rs +++ b/compiler/rustc_parse/src/parser/stmt.rs @@ -247,6 +247,22 @@ impl<'a> Parser<'a> { /// Parses a local variable declaration. fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P> { let lo = self.prev_token.span; + + if self.token.is_keyword(kw::Const) && self.look_ahead(1, |t| t.is_ident()) { + self.struct_span_err( + lo.to(self.token.span), + "`const` and `let` are mutually exclusive", + ) + .span_suggestion( + lo.to(self.token.span), + "remove `let`", + "const", + Applicability::MaybeIncorrect, + ) + .emit(); + self.bump(); + } + let (pat, colon) = self.parse_pat_before_ty(None, RecoverComma::Yes, "`let` bindings")?; let (err, ty) = if colon { From b3f32d1e8b3d9cee87358c3e8e31a7a6fcaf42df Mon Sep 17 00:00:00 2001 From: Obei Sideg Date: Thu, 4 Aug 2022 01:23:24 +0300 Subject: [PATCH 3/3] Add ui test for #99910 --- .../issue-99910-const-let-mutually-exclusive.fixed | 8 ++++++++ .../issue-99910-const-let-mutually-exclusive.rs | 8 ++++++++ ...issue-99910-const-let-mutually-exclusive.stderr | 14 ++++++++++++++ 3 files changed, 30 insertions(+) create mode 100644 src/test/ui/parser/issue-99910-const-let-mutually-exclusive.fixed create mode 100644 src/test/ui/parser/issue-99910-const-let-mutually-exclusive.rs create mode 100644 src/test/ui/parser/issue-99910-const-let-mutually-exclusive.stderr diff --git a/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.fixed b/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.fixed new file mode 100644 index 0000000000000..64ab6f62b77f3 --- /dev/null +++ b/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.fixed @@ -0,0 +1,8 @@ +// run-rustfix + +fn main() { + const _FOO: i32 = 123; + //~^ ERROR const` and `let` are mutually exclusive + const _BAR: i32 = 123; + //~^ ERROR `const` and `let` are mutually exclusive +} diff --git a/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.rs b/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.rs new file mode 100644 index 0000000000000..50520971ffb32 --- /dev/null +++ b/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.rs @@ -0,0 +1,8 @@ +// run-rustfix + +fn main() { + const let _FOO: i32 = 123; + //~^ ERROR const` and `let` are mutually exclusive + let const _BAR: i32 = 123; + //~^ ERROR `const` and `let` are mutually exclusive +} diff --git a/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.stderr b/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.stderr new file mode 100644 index 0000000000000..72377fc379cac --- /dev/null +++ b/src/test/ui/parser/issue-99910-const-let-mutually-exclusive.stderr @@ -0,0 +1,14 @@ +error: `const` and `let` are mutually exclusive + --> $DIR/issue-99910-const-let-mutually-exclusive.rs:4:5 + | +LL | const let _FOO: i32 = 123; + | ^^^^^^^^^ help: remove `let`: `const` + +error: `const` and `let` are mutually exclusive + --> $DIR/issue-99910-const-let-mutually-exclusive.rs:6:5 + | +LL | let const _BAR: i32 = 123; + | ^^^^^^^^^ help: remove `let`: `const` + +error: aborting due to 2 previous errors +