Remove a has_errors check that does not prevent follow up error noise

Author: oli-obk

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -2641,10 +2641,6 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 if let Some(e) = self.tainted_by_errors() {
                     return e;
                 }
-                if let Some(e) = self.dcx().has_errors() {
-                    // no need to overload user in such cases
-                    return e;
-                }
                 let SubtypePredicate { a_is_expected: _, a, b } = data;
                 // both must be type variables, or the other would've been instantiated
                 assert!(a.is_ty_var() && b.is_ty_var());

tests/ui/generic-const-items/parameter-defaults.stderr

@@ -8,7 +8,7 @@ error[E0282]: type annotations needed for `Option<T>`
   --> $DIR/parameter-defaults.rs:13:9
    |
 LL |     let _ = NONE;
-   |         ^
+   |         ^   ---- type must be known at this point
    |
 help: consider giving this pattern a type, where the type for type parameter `T` is specified
    |

tests/ui/parser/issues/issue-89574.rs

@@ -1,4 +1,6 @@
 fn main() {
     const EMPTY_ARRAY = [];
     //~^ missing type for `const` item
+    //~| ERROR type annotations needed
+    //~| ERROR type annotations needed
 }

tests/ui/parser/issues/issue-89574.stderr

@@ -1,8 +1,23 @@
+error[E0282]: type annotations needed
+  --> $DIR/issue-89574.rs:2:25
+   |
+LL |     const EMPTY_ARRAY = [];
+   |                         ^^ cannot infer type
+
 error: missing type for `const` item
   --> $DIR/issue-89574.rs:2:22
    |
 LL |     const EMPTY_ARRAY = [];
    |                      ^ help: provide a type for the item: `: <type>`
 
-error: aborting due to 1 previous error
+error[E0282]: type annotations needed
+  --> $DIR/issue-89574.rs:2:25
+   |
+LL |     const EMPTY_ARRAY = [];
+   |                         ^^ cannot infer type
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0282`.

tests/ui/parser/missing-closing-angle-bracket-eq-constraint.stderr

@@ -41,7 +41,7 @@ error[E0282]: type annotations needed for `Vec<_>`
   --> $DIR/missing-closing-angle-bracket-eq-constraint.rs:7:7
    |
 LL |   let v : Vec<(u32,_) = vec![];
-   |       ^
+   |       ^                 ------ type must be known at this point
    |
 help: consider giving `v` an explicit type, where the placeholders `_` are specified
    |
@@ -52,7 +52,7 @@ error[E0282]: type annotations needed for `Vec<_>`
   --> $DIR/missing-closing-angle-bracket-eq-constraint.rs:18:7
    |
 LL |   let v : Vec<'a = vec![];
-   |       ^
+   |       ^            ------ type must be known at this point
    |
 help: consider giving `v` an explicit type, where the placeholders `_` are specified
    |