add ui-suggestion-test

Author: WhyNovaa

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -43,6 +43,7 @@ use rustc_trait_selection::traits::{
     FulfillmentError, Obligation, ObligationCauseCode, supertraits,
 };
 use tracing::{debug, info, instrument};
+
 use super::probe::{AutorefOrPtrAdjustment, IsSuggestion, Mode, ProbeScope};
 use super::{CandidateSource, MethodError, NoMatchData};
 use crate::errors::{self, CandidateTraitNote, NoAssociatedItem};
@@ -3314,7 +3315,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let trait_def_id = trait_pred.def_id();
                 let adt_def_id = adt.did();
 
-                let has_impl = self.tcx.trait_impls_of(trait_def_id)
+                let has_impl = self
+                    .tcx
+                    .trait_impls_of(trait_def_id)
                     .non_blanket_impls()
                     .values()
                     .flatten()

tests/ui/suggestions/derive-clone-already-present-issue-146515.rs

@@ -0,0 +1,15 @@
+// issue: https://github.com/rust-lang/rust/issues/146515
+
+use std::rc::Rc;
+
+#[derive(Clone)]
+struct ContainsRc<T> {
+    value: Rc<T>,
+}
+
+fn clone_me<T>(x: &ContainsRc<T>) -> ContainsRc<T> {
+    x.clone()
+    //~^ ERROR mismatched types
+}
+
+fn main() {}

tests/ui/suggestions/derive-clone-already-present-issue-146515.stderr

@@ -0,0 +1,22 @@
+error[E0308]: mismatched types
+  --> $DIR/derive-clone-already-present-issue-146515.rs:11:5
+   |
+LL | fn clone_me<T>(x: &ContainsRc<T>) -> ContainsRc<T> {
+   |                                      ------------- expected `ContainsRc<T>` because of return type
+LL |     x.clone()
+   |     ^^^^^^^^^ expected `ContainsRc<T>`, found `&ContainsRc<T>`
+   |
+   = note: expected struct `ContainsRc<_>`
+           found reference `&ContainsRc<_>`
+note: `ContainsRc<T>` does not implement `Clone`, so `&ContainsRc<T>` was cloned instead
+  --> $DIR/derive-clone-already-present-issue-146515.rs:11:5
+   |
+LL |     x.clone()
+   |     ^
+   = help: `Clone` is not implemented because the trait bound `T: Clone` is not satisfied
+note: the trait `Clone` must be implemented
+  --> $SRC_DIR/core/src/clone.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.