test: add test case for impl trait arg suggestion

tests/ui/suggestions/suggest-assoc-fn-call-for-impl-trait.fixed

@@ -0,0 +1,29 @@
+// run-rustfix
+
+struct A {
+
+}
+
+trait M {
+    fn foo(_a: Self);
+    fn bar(_a: Self);
+    fn baz(_a: i32);
+}
+
+impl M for A {
+    fn foo(_a: Self) {}
+    fn bar(_a: A) {}
+    fn baz(_a: i32) {}
+}
+
+fn main() {
+    let _a = A {};
+    A::foo(_a);
+    //~^ ERROR no method named `foo` found
+    A::baz(0);
+    //~^ ERROR no method named `baz` found
+
+    let _b = A {};
+    A::bar(_b);
+    //~^ ERROR no method named `bar` found
+}

tests/ui/suggestions/suggest-assoc-fn-call-for-impl-trait.rs

@@ -0,0 +1,29 @@
+// run-rustfix
+
+struct A {
+
+}
+
+trait M {
+    fn foo(_a: Self);
+    fn bar(_a: Self);
+    fn baz(_a: i32);
+}
+
+impl M for A {
+    fn foo(_a: Self) {}
+    fn bar(_a: A) {}
+    fn baz(_a: i32) {}
+}
+
+fn main() {
+    let _a = A {};
+    _a.foo();
+    //~^ ERROR no method named `foo` found
+    _a.baz(0);
+    //~^ ERROR no method named `baz` found
+
+    let _b = A {};
+    _b.bar();
+    //~^ ERROR no method named `bar` found
+}

tests/ui/suggestions/suggest-assoc-fn-call-for-impl-trait.stderr

@@ -0,0 +1,60 @@
+error[E0599]: no method named `foo` found for struct `A` in the current scope
+  --> $DIR/suggest-assoc-fn-call-for-impl-trait.rs:21:8
+   |
+LL | struct A {
+   | -------- method `foo` not found for this struct
+...
+LL |     _a.foo();
+   |     ---^^^--
+   |     |  |
+   |     |  this is an associated function, not a method
+   |     help: use associated function syntax instead: `A::foo(_a)`
+   |
+   = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
+note: the candidate is defined in the trait `M`
+  --> $DIR/suggest-assoc-fn-call-for-impl-trait.rs:8:5
+   |
+LL |     fn foo(_a: Self);
+   |     ^^^^^^^^^^^^^^^^^
+
+error[E0599]: no method named `baz` found for struct `A` in the current scope
+  --> $DIR/suggest-assoc-fn-call-for-impl-trait.rs:23:8
+   |
+LL | struct A {
+   | -------- method `baz` not found for this struct
+...
+LL |     _a.baz(0);
+   |     ---^^^---
+   |     |  |
+   |     |  this is an associated function, not a method
+   |     help: use associated function syntax instead: `A::baz(0)`
+   |
+   = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
+note: the candidate is defined in the trait `M`
+  --> $DIR/suggest-assoc-fn-call-for-impl-trait.rs:10:5
+   |
+LL |     fn baz(_a: i32);
+   |     ^^^^^^^^^^^^^^^^
+
+error[E0599]: no method named `bar` found for struct `A` in the current scope
+  --> $DIR/suggest-assoc-fn-call-for-impl-trait.rs:27:8
+   |
+LL | struct A {
+   | -------- method `bar` not found for this struct
+...
+LL |     _b.bar();
+   |     ---^^^--
+   |     |  |
+   |     |  this is an associated function, not a method
+   |     help: use associated function syntax instead: `A::bar(_b)`
+   |
+   = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
+note: the candidate is defined in the trait `M`
+  --> $DIR/suggest-assoc-fn-call-for-impl-trait.rs:9:5
+   |
+LL |     fn bar(_a: Self);
+   |     ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0599`.