Suppress suggestions on deref in macro when == is in extern macro

Signed-off-by: xizheyin <[email protected]>

Author: xizheyin

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

@@ -449,6 +449,10 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
         err: &mut Diag<'_>,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> bool {
+        if obligation.cause.span.in_external_macro(self.infcx.tcx.sess.source_map()) {
+            return false;
+        }
+
         let mut code = obligation.cause.code();
         if let ObligationCauseCode::FunctionArg { arg_hir_id, call_hir_id, .. } = code
             && let Some(typeck_results) = &self.typeck_results

tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr

@@ -17,6 +17,16 @@ LL |     assert_eq!(y, 2);
    |     ^^^^^^^^^^^^^^^^ no implementation for `&{integer} == {integer}`
    |
    = help: the trait `PartialEq<{integer}>` is not implemented for `&{integer}`
+   = help: the following other types implement trait `PartialEq<Rhs>`:
+             f128
+             f16
+             f32
+             f64
+             i128
+             i16
+             i32
+             i64
+           and 8 others
    = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: can't compare `&{integer}` with `{integer}`