Fix suggestion when there are arguments in the method

Author: estebank

compiler/rustc_hir_typeck/src/demand.rs

@@ -392,7 +392,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ),
                     match &args[..] {
                         [] => (base.span.shrink_to_hi().with_hi(deref.span.hi()), ")".to_string()),
-                        [first, ..] => (base.span.until(first.span), String::new()),
+                        [first, ..] => (base.span.between(first.span), ", ".to_string()),
                     },
                 ]
             })

src/test/ui/suggestions/shadowed-lplace-method-2.rs

@@ -0,0 +1,23 @@
+#![allow(unused)]
+
+struct X {
+    x: (),
+}
+pub trait A {
+    fn foo(&mut self, _: usize) -> &mut ();
+}
+impl A for X {
+    fn foo(&mut self, _: usize) -> &mut () {
+        &mut self.x
+    }
+}
+impl X {
+    fn foo(&mut self, _: usize) -> &mut Self {
+        self
+    }
+}
+
+fn main() {
+    let mut x = X { x: () };
+    *x.foo(0) = (); //~ ERROR E0308
+}

src/test/ui/suggestions/shadowed-lplace-method-2.stderr

@@ -0,0 +1,25 @@
+error[E0308]: mismatched types
+  --> $DIR/shadowed-lplace-method-2.rs:22:17
+   |
+LL |     *x.foo(0) = ();
+   |     ---------   ^^ expected struct `X`, found `()`
+   |     |
+   |     expected due to the type of this binding
+   |
+note: the `foo` call is resolved to the method in `X`, shadowing the method of the same name on trait `A`
+  --> $DIR/shadowed-lplace-method-2.rs:22:8
+   |
+LL |     *x.foo(0) = ();
+   |        ^^^ refers to `X::foo`
+help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly
+   |
+LL |     *<_ as A>::foo(&mut x, 0) = ();
+   |      ++++++++++++++++++  ~
+help: try wrapping the expression in `X`
+   |
+LL |     *x.foo(0) = X { x: () };
+   |                 ++++++    +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.