From c0c69cf7d56bb11e61180aa445b3b988cdc055ca Mon Sep 17 00:00:00 2001
From: xizheyin <xizheyin@smail.nju.edu.cn>
Date: Thu, 3 Apr 2025 18:42:13 +0800
Subject: [PATCH 1/2] Add ui test

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
---
 .../dont-suggest-within-macro-issue-139251.rs | 14 +++++++
 ...t-suggest-within-macro-issue-139251.stderr | 40 +++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 tests/ui/macros/dont-suggest-within-macro-issue-139251.rs
 create mode 100644 tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr

diff --git a/tests/ui/macros/dont-suggest-within-macro-issue-139251.rs b/tests/ui/macros/dont-suggest-within-macro-issue-139251.rs
new file mode 100644
index 00000000000..ceeb6e66950
--- /dev/null
+++ b/tests/ui/macros/dont-suggest-within-macro-issue-139251.rs
@@ -0,0 +1,14 @@
+#[macro_export]
+macro_rules! is_equal {
+    ($left:expr, $right:expr) => {
+        $left == $right //~ ERROR can't compare `&{integer}` with `{integer}` [E0277]
+    };
+}
+
+fn main() {
+    let x = 1;
+    let y = &x;
+    assert!(y == 1); //~ ERROR can't compare `&{integer}` with `{integer}` [E0277]
+    assert_eq!(y, 2); //~ ERROR can't compare `&{integer}` with `{integer}` [E0277]
+    is_equal!(y, 2);
+}
diff --git a/tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr b/tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr
new file mode 100644
index 00000000000..68c32470ab0
--- /dev/null
+++ b/tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr
@@ -0,0 +1,40 @@
+error[E0277]: can't compare `&{integer}` with `{integer}`
+  --> $DIR/dont-suggest-within-macro-issue-139251.rs:11:15
+   |
+LL |     assert!(y == 1);
+   |               ^^ no implementation for `&{integer} == {integer}`
+   |
+   = help: the trait `PartialEq<{integer}>` is not implemented for `&{integer}`
+help: consider dereferencing here
+   |
+LL |     assert!(*y == 1);
+   |             +
+
+error[E0277]: can't compare `&{integer}` with `{integer}`
+  --> $DIR/dont-suggest-within-macro-issue-139251.rs:12:5
+   |
+LL |     assert_eq!(y, 2);
+   |     ^^^^^^^^^^^^^^^^ no implementation for `&{integer} == {integer}`
+   |
+   = help: the trait `PartialEq<{integer}>` is not implemented for `&{integer}`
+   = 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}`
+  --> $DIR/dont-suggest-within-macro-issue-139251.rs:4:15
+   |
+LL |         $left == $right
+   |               ^^ no implementation for `&{integer} == {integer}`
+...
+LL |     is_equal!(y, 2);
+   |     --------------- in this macro invocation
+   |
+   = help: the trait `PartialEq<{integer}>` is not implemented for `&{integer}`
+   = note: this error originates in the macro `is_equal` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider dereferencing here
+   |
+LL |     is_equal!(*y, 2);
+   |               +
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0277`.

From 7753df37def68b78d1fb2cfb5ecd1e99d0cc1c10 Mon Sep 17 00:00:00 2001
From: xizheyin <xizheyin@smail.nju.edu.cn>
Date: Sat, 5 Apr 2025 11:19:09 +0800
Subject: [PATCH 2/2] Suppress suggestions on deref in macro when == is in
 extern macro

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>
---
 .../src/error_reporting/traits/suggestions.rs          |  4 ++++
 .../dont-suggest-within-macro-issue-139251.stderr      | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
index dc8022b95c3..55010f613aa 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+++ b/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
diff --git a/tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr b/tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr
index 68c32470ab0..e4e9b169994 100644
--- a/tests/ui/macros/dont-suggest-within-macro-issue-139251.stderr
+++ b/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}`