Show more information when multiple `impl` apply

1 files changed, 50 insertions, 0 deletions

diff --git a/tests/ui/inference/multiple-impl-apply.rs b/tests/ui/inference/multiple-impl-apply.rs
new file mode 100644
index 00000000000..e6a6b928e56
--- /dev/null
+++ b/tests/ui/inference/multiple-impl-apply.rs
@@ -0,0 +1,50 @@
+struct Foo {
+    inner: u32,
+}
+
+struct Bar {
+    inner: u32,
+}
+
+#[derive(Clone, Copy)]
+struct Baz {
+    inner: u32,
+}
+
+impl From<Baz> for Bar {
+    fn from(other: Baz) -> Self {
+        Self {
+            inner: other.inner,
+        }
+    }
+}
+
+impl From<Baz> for Foo {
+    fn from(other: Baz) -> Self {
+        Self {
+            inner: other.inner,
+        }
+    }
+}
+
+fn main() {
+    let x: Baz = Baz { inner: 42 };
+
+    // DOESN'T Compile: Multiple options!
+    let y = x.into();
+    //~^ ERROR E0282
+    //~| ERROR E0283
+
+    let y_1: Foo = x.into();
+    let y_2: Bar = x.into();
+
+    let z_1 = Foo::from(y_1);
+    let z_2 = Bar::from(y_2);
+
+    // No type annotations needed, the compiler KNOWS the type must be `Foo`!
+    let m = magic_foo(x);
+}
+
+fn magic_foo(arg: Baz) -> Foo {
+    arg.into()
+}