From 6874bd27f527b6c5f40e8fd866d91813da2df35a Mon Sep 17 00:00:00 2001
From: Esteban Kuber <esteban@kuber.com.ar>
Date: Tue, 1 Mar 2022 19:40:48 +0000
Subject: [PATCH] Provide suggestion for missing `>` in a type parameter list
When encountering an inproperly terminated type parameter list, provide
a suggestion to close it after the last non-constraint type parameter
that was successfully parsed.
Fix #94058.
---
compiler/rustc_parse/src/parser/path.rs | 18 +++++++-
.../parse/trait-path-expressions.stderr | 5 +++
.../parse/trait-path-segments.stderr | 15 +++++++
.../parse/trait-path-types.stderr | 15 +++++++
src/test/ui/issues/issue-34334.stderr | 5 +++
.../ui/parser/issues/issue-20616-2.stderr | 5 +++
.../ui/parser/issues/issue-20616-3.stderr | 5 +++
.../ui/parser/issues/issue-20616-4.stderr | 5 +++
.../ui/parser/issues/issue-20616-5.stderr | 5 +++
.../ui/parser/issues/issue-20616-6.stderr | 5 +++
.../ui/parser/issues/issue-20616-7.stderr | 5 +++
src/test/ui/parser/issues/issue-62660.stderr | 5 +++
src/test/ui/parser/issues/issue-84117.stderr | 41 +++++++++++++++----
src/test/ui/parser/lifetime-semicolon.stderr | 5 +++
...closing-angle-bracket-eq-constraint.stderr | 15 +++++++
...g-closing-angle-bracket-struct-field-ty.rs | 11 +++++
...osing-angle-bracket-struct-field-ty.stderr | 15 +++++++
.../removed-syntax-closure-lifetime.stderr | 5 +++
18 files changed, 175 insertions(+), 10 deletions(-)
create mode 100644 src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.rs
create mode 100644 src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.stderr
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 07ce879de8f..596099bf2de 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -272,7 +272,23 @@ impl<'a> Parser<'a> {
lo,
ty_generics,
)?;
- self.expect_gt()?;
+ self.expect_gt().map_err(|mut err| {
+ // Attempt to find places where a missing `>` might belong.
+ if let Some(arg) = args
+ .iter()
+ .rev()
+ .skip_while(|arg| matches!(arg, AngleBracketedArg::Constraint(_)))
+ .next()
+ {
+ err.span_suggestion_verbose(
+ arg.span().shrink_to_hi(),
+ "you might have meant to end the type parameters here",
+ ">".to_string(),
+ Applicability::MaybeIncorrect,
+ );
+ }
+ err
+ })?;
let span = lo.to(self.prev_token.span);
AngleBracketedArgs { args, span }.into()
} else {
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr b/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr
index b1fea6d33a7..272afc10b17 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-expressions.stderr
@@ -13,6 +13,11 @@ LL | fn f2<'a>(arg : Box<dyn X< { 1 } = 32 >>) {}
| - ^ expected one of `,`, `:`, or `>`
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | fn f2<'a>(arg : Box<dyn X< { 1 }> = 32 >>) {}
+ | +
error: aborting due to 2 previous errors
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr b/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr
index bfb109fbfa4..7394393c05e 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-segments.stderr
@@ -5,6 +5,11 @@ LL | fn f1<'a>(arg : Box<dyn X<X::Y = u32>>) {}
| - ^ expected one of 8 possible tokens
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | fn f1<'a>(arg : Box<dyn X<X::Y> = u32>>) {}
+ | +
error: expected one of `,`, `::`, `:`, or `>`, found `=`
--> $DIR/trait-path-segments.rs:19:35
@@ -13,6 +18,11 @@ LL | impl<T : X<<Self as X>::Y<'a> = &'a u32>> Z for T {}
| - ^ expected one of `,`, `::`, `:`, or `>`
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | impl<T : X<<Self as X>::Y<'a>> = &'a u32>> Z for T {}
+ | +
error: expected one of `!`, `+`, `,`, `::`, `:`, or `>`, found `=`
--> $DIR/trait-path-segments.rs:30:25
@@ -21,6 +31,11 @@ LL | impl<T : X<X::Y<'a> = &'a u32>> Z for T {}
| - ^ expected one of `!`, `+`, `,`, `::`, `:`, or `>`
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | impl<T : X<X::Y<'a>> = &'a u32>> Z for T {}
+ | +
error: aborting due to 3 previous errors
diff --git a/src/test/ui/generic-associated-types/parse/trait-path-types.stderr b/src/test/ui/generic-associated-types/parse/trait-path-types.stderr
index c0fa41b9e0e..fe9ed579e34 100644
--- a/src/test/ui/generic-associated-types/parse/trait-path-types.stderr
+++ b/src/test/ui/generic-associated-types/parse/trait-path-types.stderr
@@ -5,6 +5,11 @@ LL | fn f<'a>(arg : Box<dyn X< [u8; 1] = u32>>) {}
| - ^ expected one of `,`, `:`, or `>`
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | fn f<'a>(arg : Box<dyn X< [u8; 1]> = u32>>) {}
+ | +
error: expected one of `,`, `:`, or `>`, found `=`
--> $DIR/trait-path-types.rs:13:37
@@ -13,6 +18,11 @@ LL | fn f1<'a>(arg : Box<dyn X<(Y<'a>) = &'a ()>>) {}
| - ^ expected one of `,`, `:`, or `>`
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | fn f1<'a>(arg : Box<dyn X<(Y<'a>)> = &'a ()>>) {}
+ | +
error: expected one of `,`, `:`, or `>`, found `=`
--> $DIR/trait-path-types.rs:18:33
@@ -21,6 +31,11 @@ LL | fn f1<'a>(arg : Box<dyn X< 'a = u32 >>) {}
| -- ^ expected one of `,`, `:`, or `>`
| |
| maybe try to close unmatched angle bracket
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | fn f1<'a>(arg : Box<dyn X< 'a> = u32 >>) {}
+ | +
error: aborting due to 3 previous errors
diff --git a/src/test/ui/issues/issue-34334.stderr b/src/test/ui/issues/issue-34334.stderr
index 49d6709a860..cd697445faf 100644
--- a/src/test/ui/issues/issue-34334.stderr
+++ b/src/test/ui/issues/issue-34334.stderr
@@ -6,6 +6,11 @@ LL | let sr: Vec<(u32, _, _) = vec![];
| | |
| | maybe try to close unmatched angle bracket
| while parsing the type for `sr`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let sr: Vec<(u32, _, _)> = vec![];
+ | +
error[E0277]: a value of type `Vec<(u32, _, _)>` cannot be built from an iterator over elements of type `()`
--> $DIR/issue-34334.rs:5:87
diff --git a/src/test/ui/parser/issues/issue-20616-2.stderr b/src/test/ui/parser/issues/issue-20616-2.stderr
index 01e3d3dd7cc..13e6aa7d605 100644
--- a/src/test/ui/parser/issues/issue-20616-2.stderr
+++ b/src/test/ui/parser/issues/issue-20616-2.stderr
@@ -3,6 +3,11 @@ error: expected one of `,`, `:`, `=`, or `>`, found `(`
|
LL | type Type_2 = Type_1_<'static ()>;
| ^ expected one of `,`, `:`, `=`, or `>`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type Type_2 = Type_1_<'static> ()>;
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-20616-3.stderr b/src/test/ui/parser/issues/issue-20616-3.stderr
index b535c7a3267..dbff116e505 100644
--- a/src/test/ui/parser/issues/issue-20616-3.stderr
+++ b/src/test/ui/parser/issues/issue-20616-3.stderr
@@ -3,6 +3,11 @@ error: expected one of `>`, a const expression, lifetime, or type, found `,`
|
LL | type Type_3<T> = Box<T,,>;
| ^ expected one of `>`, a const expression, lifetime, or type
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type Type_3<T> = Box<T>,,>;
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-20616-4.stderr b/src/test/ui/parser/issues/issue-20616-4.stderr
index 2b3b75f3119..48a06e00b24 100644
--- a/src/test/ui/parser/issues/issue-20616-4.stderr
+++ b/src/test/ui/parser/issues/issue-20616-4.stderr
@@ -3,6 +3,11 @@ error: expected one of `>`, a const expression, lifetime, or type, found `,`
|
LL | type Type_4<T> = Type_1_<'static,, T>;
| ^ expected one of `>`, a const expression, lifetime, or type
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type Type_4<T> = Type_1_<'static>,, T>;
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-20616-5.stderr b/src/test/ui/parser/issues/issue-20616-5.stderr
index 1ec1dbde695..84bee2ad184 100644
--- a/src/test/ui/parser/issues/issue-20616-5.stderr
+++ b/src/test/ui/parser/issues/issue-20616-5.stderr
@@ -3,6 +3,11 @@ error: expected one of `>`, a const expression, lifetime, or type, found `,`
|
LL | type Type_5<'a> = Type_1_<'a, (),,>;
| ^ expected one of `>`, a const expression, lifetime, or type
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type Type_5<'a> = Type_1_<'a, ()>,,>;
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-20616-6.stderr b/src/test/ui/parser/issues/issue-20616-6.stderr
index 7401abdd091..67de41b9747 100644
--- a/src/test/ui/parser/issues/issue-20616-6.stderr
+++ b/src/test/ui/parser/issues/issue-20616-6.stderr
@@ -3,6 +3,11 @@ error: expected one of `>`, a const expression, lifetime, or type, found `,`
|
LL | type Type_6 = Type_5_<'a,,>;
| ^ expected one of `>`, a const expression, lifetime, or type
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type Type_6 = Type_5_<'a>,,>;
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-20616-7.stderr b/src/test/ui/parser/issues/issue-20616-7.stderr
index e2c3efe8447..3b8e07fa0d0 100644
--- a/src/test/ui/parser/issues/issue-20616-7.stderr
+++ b/src/test/ui/parser/issues/issue-20616-7.stderr
@@ -3,6 +3,11 @@ error: expected one of `>`, a const expression, lifetime, or type, found `,`
|
LL | type Type_7 = Box<(),,>;
| ^ expected one of `>`, a const expression, lifetime, or type
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type Type_7 = Box<()>,,>;
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-62660.stderr b/src/test/ui/parser/issues/issue-62660.stderr
index a50ada9056b..be0b9a524df 100644
--- a/src/test/ui/parser/issues/issue-62660.stderr
+++ b/src/test/ui/parser/issues/issue-62660.stderr
@@ -3,6 +3,11 @@ error: expected one of `!`, `(`, `+`, `,`, `::`, `:`, `<`, `=`, or `>`, found `)
|
LL | pub fn foo(_: i32, self: Box<Self) {}
| ^ expected one of 9 possible tokens
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | pub fn foo(_: i32, self: Box<Self>) {}
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/issues/issue-84117.stderr b/src/test/ui/parser/issues/issue-84117.stderr
index 5b9cc53baa5..a2407affeef 100644
--- a/src/test/ui/parser/issues/issue-84117.stderr
+++ b/src/test/ui/parser/issues/issue-84117.stderr
@@ -2,10 +2,18 @@ error: expected one of `>`, a const expression, lifetime, or type, found `}`
--> $DIR/issue-84117.rs:2:67
|
LL | let outer_local:e_outer<&str, { let inner_local:e_inner<&str, }
- | ------------ ^ expected one of `>`, a const expression, lifetime, or type
- | | |
- | | help: use `=` if you meant to assign
+ | ----------- ^ expected one of `>`, a const expression, lifetime, or type
+ | |
| while parsing the type for `inner_local`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let outer_local:e_outer<&str, { let inner_local:e_inner<&str>, }
+ | +
+help: use `=` if you meant to assign
+ |
+LL | let outer_local:e_outer<&str, { let inner_local =e_inner<&str, }
+ | ~
error: expected one of `!`, `.`, `::`, `;`, `?`, `else`, `{`, or an operator, found `,`
--> $DIR/issue-84117.rs:2:65
@@ -17,21 +25,36 @@ error: expected one of `,`, `:`, `=`, or `>`, found `}`
--> $DIR/issue-84117.rs:8:1
|
LL | let outer_local:e_outer<&str, { let inner_local:e_inner<&str, }
- | ------------ help: use `=` if you meant to assign - expected one of `,`, `:`, `=`, or `>`
- | |
- | while parsing the type for `outer_local`
+ | ----------- while parsing the type for `outer_local` - expected one of `,`, `:`, `=`, or `>`
...
LL | }
| ^ unexpected token
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let outer_local:e_outer<&str, { let inner_local:e_inner<&str, }>
+ | +
+help: use `=` if you meant to assign
+ |
+LL | let outer_local =e_outer<&str, { let inner_local:e_inner<&str, }
+ | ~
error: expected one of `>`, a const expression, lifetime, or type, found `}`
--> $DIR/issue-84117.rs:2:67
|
LL | let outer_local:e_outer<&str, { let inner_local:e_inner<&str, }
- | ------------ ^ expected one of `>`, a const expression, lifetime, or type
- | | |
- | | help: use `=` if you meant to assign
+ | ----------- ^ expected one of `>`, a const expression, lifetime, or type
+ | |
| while parsing the type for `inner_local`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let outer_local:e_outer<&str, { let inner_local:e_inner<&str>, }
+ | +
+help: use `=` if you meant to assign
+ |
+LL | let outer_local:e_outer<&str, { let inner_local =e_inner<&str, }
+ | ~
error: expected one of `!`, `.`, `::`, `;`, `?`, `else`, `{`, or an operator, found `,`
--> $DIR/issue-84117.rs:2:65
diff --git a/src/test/ui/parser/lifetime-semicolon.stderr b/src/test/ui/parser/lifetime-semicolon.stderr
index 3b67705aae9..948f9655e1e 100644
--- a/src/test/ui/parser/lifetime-semicolon.stderr
+++ b/src/test/ui/parser/lifetime-semicolon.stderr
@@ -3,6 +3,11 @@ error: expected one of `,`, `:`, `=`, or `>`, found `;`
|
LL | fn foo<'a, 'b>(x: &mut Foo<'a; 'b>) {}
| ^ expected one of `,`, `:`, `=`, or `>`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | fn foo<'a, 'b>(x: &mut Foo<'a>; 'b>) {}
+ | +
error: aborting due to previous error
diff --git a/src/test/ui/parser/missing-closing-angle-bracket-eq-constraint.stderr b/src/test/ui/parser/missing-closing-angle-bracket-eq-constraint.stderr
index 93403372bcb..427234e97cf 100644
--- a/src/test/ui/parser/missing-closing-angle-bracket-eq-constraint.stderr
+++ b/src/test/ui/parser/missing-closing-angle-bracket-eq-constraint.stderr
@@ -6,6 +6,11 @@ LL | let v : Vec<(u32,_) = vec![];
| | |
| | maybe try to close unmatched angle bracket
| while parsing the type for `v`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let v : Vec<(u32,_)> = vec![];
+ | +
error: expected one of `!`, `(`, `+`, `,`, `::`, `<`, or `>`, found `{`
--> $DIR/missing-closing-angle-bracket-eq-constraint.rs:13:32
@@ -14,6 +19,11 @@ LL | let foo : Foo::<T1, T2 = Foo {_a : arg1, _b : arg2};
| --- ^ expected one of 7 possible tokens
| |
| while parsing the type for `foo`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let foo : Foo::<T1>, T2 = Foo {_a : arg1, _b : arg2};
+ | +
error: expected one of `,`, `:`, or `>`, found `=`
--> $DIR/missing-closing-angle-bracket-eq-constraint.rs:18:18
@@ -23,6 +33,11 @@ LL | let v : Vec<'a = vec![];
| | |
| | maybe try to close unmatched angle bracket
| while parsing the type for `v`
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | let v : Vec<'a> = vec![];
+ | +
error[E0282]: type annotations needed for `Vec<T>`
--> $DIR/missing-closing-angle-bracket-eq-constraint.rs:7:25
diff --git a/src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.rs b/src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.rs
new file mode 100644
index 00000000000..d69a56c51d3
--- /dev/null
+++ b/src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.rs
@@ -0,0 +1,11 @@
+// run-rustifx
+#![allow(unused)]
+use std::sync::{Arc, Mutex};
+
+pub struct Foo {
+ a: Mutex<usize>,
+ b: Arc<Mutex<usize>, //~ HELP you might have meant to end the type parameters here
+ c: Arc<Mutex<usize>>,
+} //~ ERROR expected one of
+
+fn main() {}
diff --git a/src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.stderr b/src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.stderr
new file mode 100644
index 00000000000..46ca1f06be6
--- /dev/null
+++ b/src/test/ui/parser/missing-closing-angle-bracket-struct-field-ty.stderr
@@ -0,0 +1,15 @@
+error: expected one of `>`, a const expression, lifetime, or type, found `}`
+ --> $DIR/missing-closing-angle-bracket-struct-field-ty.rs:9:1
+ |
+LL | c: Arc<Mutex<usize>>,
+ | - expected one of `>`, a const expression, lifetime, or type
+LL | }
+ | ^ unexpected token
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | b: Arc<Mutex<usize>>,
+ | +
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/removed-syntax-closure-lifetime.stderr b/src/test/ui/parser/removed-syntax-closure-lifetime.stderr
index 63b6e138ce5..e107c6b78b3 100644
--- a/src/test/ui/parser/removed-syntax-closure-lifetime.stderr
+++ b/src/test/ui/parser/removed-syntax-closure-lifetime.stderr
@@ -3,6 +3,11 @@ error: expected one of `!`, `(`, `+`, `,`, `::`, `:`, `<`, `=`, or `>`, found `/
|
LL | type closure = Box<lt/fn()>;
| ^ expected one of 9 possible tokens
+ |
+help: you might have meant to end the type parameters here
+ |
+LL | type closure = Box<lt>/fn()>;
+ | +
error: aborting due to previous error