Add tests for checking the impl self type

crates/ra_hir_ty/src/tests.rs

@@ -3433,6 +3433,20 @@ pub fn baz() -> usize { 31usize }
     assert_eq!("(i32, usize)", type_at_pos(&db, pos));
 }
 
+#[test]
+fn method_resolution_unify_impl_self_type() {
+    let t = type_at(
+        r#"
+//- /main.rs
+struct S<T>;
+impl S<u32> { fn foo(&self) -> u8 {} }
+impl S<i32> { fn foo(&self) -> i8 {} }
+fn test() { (S::<u32>.foo(), S::<i32>.foo())<|>; }
+"#,
+    );
+    assert_eq!(t, "(u8, i8)");
+}
+
 #[test]
 fn method_resolution_trait_before_autoref() {
     let t = type_at(

crates/ra_ide/src/completion/complete_dot.rs

@@ -216,6 +216,39 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_method_completion_only_fitting_impls() {
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+            struct A<T> {}
+            impl A<u32> {
+                fn the_method(&self) {}
+            }
+            impl A<i32> {
+                fn the_other_method(&self) {}
+            }
+            fn foo(a: A<u32>) {
+               a.<|>
+            }
+            ",
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "the_method()",
+                source_range: [243; 243),
+                delete: [243; 243),
+                insert: "the_method()$0",
+                kind: Method,
+                lookup: "the_method",
+                detail: "fn the_method(&self)",
+            },
+        ]
+        "###
+        );
+    }
+
     #[test]
     fn test_trait_method_completion() {
         assert_debug_snapshot!(