Alternative wording for inference failure

rust-lang · Jun 1, 2019 · 65c2a7b · 65c2a7b
1 parent 8bb094d
commit 65c2a7b
Show file tree

Hide file tree

Showing 15 changed files with 42 additions and 52 deletions.
diff --git a/src/librustc/infer/error_reporting/need_type_info.rs b/src/librustc/infer/error_reporting/need_type_info.rs
@@ -15,7 +15,7 @@ struct FindLocalByTypeVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     hir_map: &'a hir::map::Map<'gcx>,
     found_local_pattern: Option<&'gcx Pat>,
     found_arg_pattern: Option<&'gcx Pat>,
-    found_ty: Option<Ty<'tcx>>,
+    found_ty: Option<String>,
 }
 
 impl<'a, 'gcx, 'tcx> FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
@@ -55,7 +55,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
     fn visit_local(&mut self, local: &'gcx Local) {
         if let (None, Some(ty)) = (self.found_local_pattern, self.node_matches_type(local.hir_id)) {
             self.found_local_pattern = Some(&*local.pat);
-            self.found_ty = Some(ty);
+            self.found_ty = Some(ty.to_string());
         }
         intravisit::walk_local(self, local);
     }
@@ -67,7 +67,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
                 self.node_matches_type(argument.hir_id),
             ) {
                 self.found_arg_pattern = Some(&*argument.pat);
-                self.found_ty = Some(ty);
+                self.found_ty = Some(ty.to_string());
             }
         }
         intravisit::walk_body(self, body);
@@ -108,7 +108,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         let name = self.extract_type_name(&ty, None);
 
         let mut err_span = span;
-        let mut labels = vec![(span, InferCtxt::missing_type_msg(&name))];
 
         let mut local_visitor = FindLocalByTypeVisitor {
             infcx: &self,
@@ -124,10 +123,12 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             local_visitor.visit_expr(expr);
         }
 
-        let ty_msg = match local_visitor.found_ty {
+        let ty_msg = match &local_visitor.found_ty {
-            Some(ty) if &ty.to_string() != "_" => format!(" for `{}`", ty),
+            Some(ty) if &ty[..] != "_" && ty != &name => format!(" in `{}`", ty),
             _ => String::new(),
         };
+        let mut labels = vec![(span, InferCtxt::missing_type_msg(&name, &ty_msg))];
+
         if let Some(pattern) = local_visitor.found_arg_pattern {
             err_span = pattern.span;
             // We don't want to show the default label for closures.
@@ -148,8 +149,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             labels.clear();
             labels.push((pattern.span, format!(
                 "consider giving this closure parameter {}",
-                match local_visitor.found_ty {
+                match &local_visitor.found_ty {
-                    Some(ty) if &ty.to_string() != "_" => format!(
+                    Some(ty) if &ty[..] != "_" && ty != &name => format!(
                         "the type `{}` with the type parameter `{}` specified",
                         ty,
                         name,
@@ -162,18 +163,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 match pattern.span.compiler_desugaring_kind() {
                     None => labels.push((
                         pattern.span,
-                        format!(
+                        format!("consider giving `{}` a type", simple_ident),
-                            "consider giving `{}` {}",
-                            simple_ident,
-                            match local_visitor.found_ty {
-                                Some(ty) if &ty.to_string() != "_" => format!(
-                                    "the type `{}` with the type parameter `{}` specified",
-                                    ty,
-                                    name,
-                                ),
-                                _ => "a type".to_owned(),
-                            },
-                        ),
                     )),
                     Some(CompilerDesugaringKind::ForLoop) => labels.push((
                         pattern.span,
@@ -213,15 +203,15 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                        span,
                        E0698,
                        "type inside generator must be known in this context");
-        err.span_label(span, InferCtxt::missing_type_msg(&name));
+        err.span_label(span, InferCtxt::missing_type_msg(&name, ""));
         err
     }
 
-    fn missing_type_msg(type_name: &str) -> String {
+    fn missing_type_msg(type_name: &str, postfix: &str) -> String {
         if type_name == "_" {
             "cannot infer type".to_owned()
         } else {
-            format!("cannot infer type for `{}`", type_name)
+            format!("cannot infer type for `{}`{}", type_name, postfix)
         }
     }
 }
diff --git a/src/test/ui/issues/issue-12187-1.stderr b/src/test/ui/issues/issue-12187-1.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed for `&_`
+error[E0282]: type annotations needed in `&_`
   --> $DIR/issue-12187-1.rs:6:10
    |
 LL |     let &v = new();

diff --git a/src/test/ui/issues/issue-12187-2.stderr b/src/test/ui/issues/issue-12187-2.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed for `&_`
+error[E0282]: type annotations needed in `&_`
   --> $DIR/issue-12187-2.rs:6:10
    |
 LL |     let &v = new();

diff --git a/src/test/ui/issues/issue-17551.stderr b/src/test/ui/issues/issue-17551.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `B<_>`
+error[E0282]: type annotations needed in `B<_>`
   --> $DIR/issue-17551.rs:6:15
    |
 LL |     let foo = B(marker::PhantomData);
-   |         ---   ^ cannot infer type for `T`
+   |         ---   ^ cannot infer type for `T` in `B<_>`
    |         |
-   |         consider giving `foo` the type `B<_>` with the type parameter `T` specified
+   |         consider giving `foo` a type
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/issues/issue-20261.stderr b/src/test/ui/issues/issue-20261.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed for `&(_,)`
+error[E0282]: type annotations needed in `&(_,)`
   --> $DIR/issue-20261.rs:4:11
    |
 LL |     for (ref i,) in [].iter() {

diff --git a/src/test/ui/issues/issue-23046.stderr b/src/test/ui/issues/issue-23046.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed for `Expr<'_, _>`
+error[E0282]: type annotations needed in `Expr<'_, _>`
   --> $DIR/issue-23046.rs:17:15
    |
 LL |     let ex = |x| {

diff --git a/src/test/ui/issues/issue-25368.stderr b/src/test/ui/issues/issue-25368.stderr
@@ -1,11 +1,11 @@
-error[E0282]: type annotations needed for `(std::sync::mpsc::Sender<Foo<_>>, std::sync::mpsc::Receiver<Foo<_>>)`
+error[E0282]: type annotations needed in `(std::sync::mpsc::Sender<Foo<_>>, std::sync::mpsc::Receiver<Foo<_>>)`
   --> $DIR/issue-25368.rs:11:17
    |
 LL |     let (tx, rx) = channel();
    |         -------- consider giving the pattern a type
 ...
 LL |         tx.send(Foo{ foo: PhantomData });
-   |                 ^^^ cannot infer type for `T`
+   |                 ^^^ cannot infer type for `T` in `(std::sync::mpsc::Sender<Foo<_>>, std::sync::mpsc::Receiver<Foo<_>>)`
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/issues/issue-7813.stderr b/src/test/ui/issues/issue-7813.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `&[_; 0]`
+error[E0282]: type annotations needed in `&[_; 0]`
   --> $DIR/issue-7813.rs:2:13
    |
 LL |     let v = &[];
    |         -   ^^^ cannot infer type
    |         |
-   |         consider giving `v` the type `&[_; 0]` with the type parameter `_` specified
+   |         consider giving `v` a type
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/methods/method-ambig-one-trait-unknown-int-type.stderr b/src/test/ui/methods/method-ambig-one-trait-unknown-int-type.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `std::vec::Vec<_>`
+error[E0282]: type annotations needed in `std::vec::Vec<_>`
   --> $DIR/method-ambig-one-trait-unknown-int-type.rs:24:17
    |
 LL |     let mut x = Vec::new();
-   |         -----   ^^^^^^^^ cannot infer type for `T`
+   |         -----   ^^^^^^^^ cannot infer type for `T` in `std::vec::Vec<_>`
    |         |
-   |         consider giving `x` the type `std::vec::Vec<_>` with the type parameter `T` specified
+   |         consider giving `x` a type
 
 error[E0308]: mismatched types
   --> $DIR/method-ambig-one-trait-unknown-int-type.rs:33:20

diff --git a/src/test/ui/span/issue-42234-unknown-receiver-type.stderr b/src/test/ui/span/issue-42234-unknown-receiver-type.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `std::option::Option<_>`
+error[E0282]: type annotations needed in `std::option::Option<_>`
   --> $DIR/issue-42234-unknown-receiver-type.rs:7:5
    |
 LL |     let x: Option<_> = None;
-   |         - consider giving `x` the type `std::option::Option<_>` with the type parameter `T` specified
+   |         - consider giving `x` a type
 LL |     x.unwrap().method_that_could_exist_on_some_type();
-   |     ^^^^^^^^^^ cannot infer type for `T`
+   |     ^^^^^^^^^^ cannot infer type for `T` in `std::option::Option<_>`
    |
    = note: type must be known at this point
 

diff --git a/src/test/ui/type/type-check/cannot_infer_local_or_array.stderr b/src/test/ui/type/type-check/cannot_infer_local_or_array.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `[_; 0]`
+error[E0282]: type annotations needed in `[_; 0]`
   --> $DIR/cannot_infer_local_or_array.rs:2:13
    |
 LL |     let x = [];
    |         -   ^^ cannot infer type
    |         |
-   |         consider giving `x` the type `[_; 0]` with the type parameter `_` specified
+   |         consider giving `x` a type
 
 error: aborting due to previous error
 

diff --git a/src/test/ui/type/type-check/cannot_infer_local_or_vec.stderr b/src/test/ui/type/type-check/cannot_infer_local_or_vec.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `std::vec::Vec<_>`
+error[E0282]: type annotations needed in `std::vec::Vec<_>`
   --> $DIR/cannot_infer_local_or_vec.rs:2:13
    |
 LL |     let x = vec![];
-   |         -   ^^^^^^ cannot infer type for `T`
+   |         -   ^^^^^^ cannot infer type for `T` in `std::vec::Vec<_>`
    |         |
-   |         consider giving `x` the type `std::vec::Vec<_>` with the type parameter `T` specified
+   |         consider giving `x` a type
    |
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 

diff --git a/src/test/ui/type/type-check/cannot_infer_local_or_vec_in_tuples.stderr b/src/test/ui/type/type-check/cannot_infer_local_or_vec_in_tuples.stderr
@@ -1,8 +1,8 @@
-error[E0282]: type annotations needed for `(std::vec::Vec<_>,)`
+error[E0282]: type annotations needed in `(std::vec::Vec<_>,)`
   --> $DIR/cannot_infer_local_or_vec_in_tuples.rs:2:18
    |
 LL |     let (x, ) = (vec![], );
-   |         -----    ^^^^^^ cannot infer type for `T`
+   |         -----    ^^^^^^ cannot infer type for `T` in `(std::vec::Vec<_>,)`
    |         |
    |         consider giving the pattern a type
    |

diff --git a/src/test/ui/unboxed-closures/unboxed-closures-failed-recursive-fn-2.stderr b/src/test/ui/unboxed-closures/unboxed-closures-failed-recursive-fn-2.stderr
@@ -1,8 +1,8 @@
-error[E0282]: type annotations needed for `std::option::Option<_>`
+error[E0282]: type annotations needed in `std::option::Option<_>`
   --> $DIR/unboxed-closures-failed-recursive-fn-2.rs:16:32
    |
 LL |     let mut closure0 = None;
-   |         ------------ consider giving `closure0` the type `std::option::Option<_>` with the type parameter `_` specified
+   |         ------------ consider giving `closure0` a type
 ...
 LL |                         return c();
    |                                ^^^ cannot infer type

diff --git a/src/test/ui/vector-no-ann.stderr b/src/test/ui/vector-no-ann.stderr
@@ -1,10 +1,10 @@
-error[E0282]: type annotations needed for `std::vec::Vec<_>`
+error[E0282]: type annotations needed in `std::vec::Vec<_>`
   --> $DIR/vector-no-ann.rs:2:16
    |
 LL |     let _foo = Vec::new();
-   |         ----   ^^^^^^^^ cannot infer type for `T`
+   |         ----   ^^^^^^^^ cannot infer type for `T` in `std::vec::Vec<_>`
    |         |
-   |         consider giving `_foo` the type `std::vec::Vec<_>` with the type parameter `T` specified
+   |         consider giving `_foo` a type
 
 error: aborting due to previous error