diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index c4add4dbdfb2f..aa1294d2c3acb 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -856,6 +856,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             format!("impl {}", all_bounds_str),
             Applicability::MaybeIncorrect,
         );
+
+        let ty::Param(found_ty_as_param) = found.kind() else { return };
+        err.note(format!("the type of `{}` is chosen by the caller and may be a type that is different from `{}`", expected_ty_as_param.name, found_ty_as_param.name));
     }
 
     pub(in super::super) fn suggest_missing_break_or_return_expr(
diff --git a/tests/ui/return/return-impl-trait-bad.stderr b/tests/ui/return/return-impl-trait-bad.stderr
index 237b85ee66a10..30d7dd4f9541d 100644
--- a/tests/ui/return/return-impl-trait-bad.stderr
+++ b/tests/ui/return/return-impl-trait-bad.stderr
@@ -53,6 +53,7 @@ LL |     "don't suggest this, because the generic param is used in the bound."
    |
    = note: expected type parameter `T`
                    found reference `&'static str`
+   = note: the type of `T` is chosen by the caller and may be a type that is different than `T`
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/return/return-impl-trait.stderr b/tests/ui/return/return-impl-trait.stderr
index 43d40972fcac0..55e52d323ff24 100644
--- a/tests/ui/return/return-impl-trait.stderr
+++ b/tests/ui/return/return-impl-trait.stderr
@@ -12,6 +12,7 @@ LL |     ()
    |
    = note: expected type parameter `T`
                    found unit type `()`
+   = note: the type of `T` is chosen by the caller and may be a type that is different than `T`
 
 error[E0308]: mismatched types
   --> $DIR/return-impl-trait.rs:23:5
@@ -28,6 +29,7 @@ LL |     ()
    |
    = note: expected type parameter `T`
                    found unit type `()`
+   = note: the type of `T` is chosen by the caller and may be a type that is different than `T`
 
 error: aborting due to 2 previous errors