1 files changed, 75 insertions, 0 deletions
diff --git a/tests/ui/resolve/issue-21221-1.rs b/tests/ui/resolve/issue-21221-1.rs
new file mode 100644
index 00000000000..b180624d2f4
--- /dev/null
+++ b/tests/ui/resolve/issue-21221-1.rs
@@ -0,0 +1,75 @@
+mod mul1 {
+    pub trait Mul {}
+}
+
+mod mul2 {
+    pub trait Mul {}
+}
+
+mod mul3 {
+    enum Mul {
+      Yes,
+      No
+    }
+}
+
+mod mul4 {
+    type Mul = String;
+}
+
+mod mul5 {
+    struct Mul{
+        left_term: u32,
+        right_term: u32
+    }
+}
+
+#[derive(Debug)]
+struct Foo;
+
+// When we comment the next line:
+//use mul1::Mul;
+
+// BEFORE, we got the following error for the `impl` below:
+//   error: use of undeclared trait name `Mul` [E0405]
+// AFTER, we get this message:
+//   error: trait `Mul` is not in scope.
+//   help: ...
+//   help: you can import several candidates into scope (`use ...;`):
+//   help:   `mul1::Mul`
+//   help:   `mul2::Mul`
+//   help:   `std::ops::Mul`
+
+impl Mul for Foo {
+//~^ ERROR cannot find trait `Mul`
+}
+
+// BEFORE, we got:
+//   error: use of undeclared type name `Mul` [E0412]
+// AFTER, we get:
+//   error: type name `Mul` is not in scope. Maybe you meant:
+//   help: ...
+//   help: you can import several candidates into scope (`use ...;`):
+//   help:   `mul1::Mul`
+//   help:   `mul2::Mul`
+//   help:   `mul3::Mul`
+//   help:   `mul4::Mul`
+//   help:   and 2 other candidates
+fn getMul() -> Mul {
+//~^ ERROR cannot find type `Mul`
+}
+
+// Let's also test what happens if the trait doesn't exist:
+impl ThisTraitReallyDoesntExistInAnyModuleReally for Foo {
+//~^ ERROR cannot find trait `ThisTraitReallyDoesntExistInAnyModuleReally`
+}
+
+// Let's also test what happens if there's just one alternative:
+impl Div for Foo {
+//~^ ERROR cannot find trait `Div`
+}
+
+fn main() {
+    let foo = Foo();
+    println!("Hello, {:?}!", foo);
+}