fix `own_substs` ICE

2 files changed, 32 insertions, 0 deletions

diff --git a/src/test/ui/inference/need_type_info/issue-103053.rs b/src/test/ui/inference/need_type_info/issue-103053.rs
new file mode 100644
index 00000000000..05169666f83
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/issue-103053.rs
@@ -0,0 +1,18 @@
+trait TypeMapper {
+    type MapType;
+}
+
+type Mapped<T> = <T as TypeMapper>::MapType;
+
+struct Test {}
+
+impl TypeMapper for () {
+    type MapType = Test;
+}
+
+fn test() {
+    Mapped::<()> {};
+    None; //~ ERROR type annotations needed
+}
+
+fn main() {}
diff --git a/src/test/ui/inference/need_type_info/issue-103053.stderr b/src/test/ui/inference/need_type_info/issue-103053.stderr
new file mode 100644
index 00000000000..84f0475d8cd
--- /dev/null
+++ b/src/test/ui/inference/need_type_info/issue-103053.stderr
@@ -0,0 +1,14 @@
+error[E0282]: type annotations needed
+  --> $DIR/issue-103053.rs:15:5
+   |
+LL |     None;
+   |     ^^^^ cannot infer type of the type parameter `T` declared on the enum `Option`
+   |
+help: consider specifying the generic argument
+   |
+LL |     None::<T>;
+   |         +++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.