Rollup merge of #33107 - sanxiyn:prev-impl-item, r=eddyb

Show previous definition of duplicate impl item

Fix #32971.

src/test/compile-fail/impl-duplicate-methods.rs

@@ -9,9 +9,10 @@
 // except according to those terms.
 
 struct Foo;
+
 impl Foo {
-    fn orange(&self){}
-    fn orange(&self){}   //~ ERROR duplicate definitions
+    fn orange(&self) {} //~ NOTE previous definition of `orange` here
+    fn orange(&self) {} //~ ERROR duplicate definitions with name `orange`
 }
 
 fn main() {}