Remove unnecessary label

Author: estebank

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

@@ -2312,14 +2312,17 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                         _ => self.tcx.typeck(parent_id),
                     };
                     let ty = typeck_results.expr_ty_adjusted(expr);
-                    err.span_label(
-                        expr.peel_blocks().span,
-                        &if ty.references_error() {
-                            String::new()
-                        } else {
-                            format!("this tail expression is of type `{:?}`", ty)
-                        },
-                    );
+                    let span = expr.peel_blocks().span;
+                    if Some(span) != err.span.primary_span() {
+                        err.span_label(
+                            span,
+                            &if ty.references_error() {
+                                String::new()
+                            } else {
+                                format!("this tail expression is of type `{:?}`", ty)
+                            },
+                        );
+                    }
                 }
                 if let Some(Node::Expr(hir::Expr {
                     kind:
@@ -2328,7 +2331,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     ..
                 })) = hir.find(call_hir_id)
                 {
-                    err.span_label(*span, "required by a bound introduced by this call");
+                    if Some(*span) != err.span.primary_span() {
+                        err.span_label(*span, "required by a bound introduced by this call");
+                    }
                 }
                 ensure_sufficient_stack(|| {
                     self.note_obligation_cause_code(

src/test/ui/derives/derives-span-Clone-enum-struct-variant.stderr

@@ -5,10 +5,7 @@ LL | #[derive(Clone)]
    |          ----- in this derive macro expansion
 ...
 LL |      x: Error
-   |      ^^^^^^^^
-   |      |
-   |      the trait `Clone` is not implemented for `Error`
-   |      required by a bound introduced by this call
+   |      ^^^^^^^^ the trait `Clone` is not implemented for `Error`
    |
 note: required by `clone`
   --> $SRC_DIR/core/src/clone.rs:LL:COL

src/test/ui/derives/derives-span-Clone-enum.stderr

@@ -5,10 +5,7 @@ LL | #[derive(Clone)]
    |          ----- in this derive macro expansion
 ...
 LL |      Error
-   |      ^^^^^
-   |      |
-   |      the trait `Clone` is not implemented for `Error`
-   |      required by a bound introduced by this call
+   |      ^^^^^ the trait `Clone` is not implemented for `Error`
    |
 note: required by `clone`
   --> $SRC_DIR/core/src/clone.rs:LL:COL

src/test/ui/derives/derives-span-Clone-struct.stderr

@@ -5,10 +5,7 @@ LL | #[derive(Clone)]
    |          ----- in this derive macro expansion
 LL | struct Struct {
 LL |     x: Error
-   |     ^^^^^^^^
-   |     |
-   |     the trait `Clone` is not implemented for `Error`
-   |     required by a bound introduced by this call
+   |     ^^^^^^^^ the trait `Clone` is not implemented for `Error`
    |
 note: required by `clone`
   --> $SRC_DIR/core/src/clone.rs:LL:COL

src/test/ui/derives/derives-span-Clone-tuple-struct.stderr

@@ -5,10 +5,7 @@ LL | #[derive(Clone)]
    |          ----- in this derive macro expansion
 LL | struct Struct(
 LL |     Error
-   |     ^^^^^
-   |     |
-   |     the trait `Clone` is not implemented for `Error`
-   |     required by a bound introduced by this call
+   |     ^^^^^ the trait `Clone` is not implemented for `Error`
    |
 note: required by `clone`
   --> $SRC_DIR/core/src/clone.rs:LL:COL

src/test/ui/derives/deriving-no-inner-impl-error-message.stderr

@@ -29,10 +29,7 @@ LL | #[derive(Clone)]
    |          ----- in this derive macro expansion
 LL | struct C {
 LL |     x: NoCloneOrEq
-   |     ^^^^^^^^^^^^^^
-   |     |
-   |     the trait `Clone` is not implemented for `NoCloneOrEq`
-   |     required by a bound introduced by this call
+   |     ^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `NoCloneOrEq`
    |
 note: required by `clone`
   --> $SRC_DIR/core/src/clone.rs:LL:COL

src/test/ui/rfc-1937-termination-trait/termination-trait-test-wrong-type.stderr

@@ -6,10 +6,7 @@ LL |   #[test]
 LL | / fn can_parse_zero_as_f32() -> Result<f32, ParseFloatError> {
 LL | |     "0".parse()
 LL | | }
-   | | ^
-   | | |
-   | |_`main` can only return types that implement `Termination`
-   |   required by a bound introduced by this call
+   | |_^ `main` can only return types that implement `Termination`
    |
    = help: the trait `Termination` is not implemented for `Result<f32, ParseFloatError>`
 note: required by a bound in `assert_test_result`

src/test/ui/traits/issue-71136.stderr

@@ -5,10 +5,7 @@ LL | #[derive(Clone)]
    |          ----- in this derive macro expansion
 LL | struct FooHolster {
 LL |     the_foos: Vec<Foo>,
-   |     ^^^^^^^^^^^^^^^^^^
-   |     |
-   |     expected an implementor of trait `Clone`
-   |     required by a bound introduced by this call
+   |     ^^^^^^^^^^^^^^^^^^ expected an implementor of trait `Clone`
    |
    = note: required because of the requirements on the impl of `Clone` for `Vec<Foo>`
 note: required by `clone`