Add test.

src/test/ui/mir/mir-inlining/ice-issue-100550-unnormalized-projection.rs

@@ -0,0 +1,30 @@
+// This test verifies that we do not ICE due to MIR inlining in case of normalization failure
+// in a projection.
+//
+// compile-flags: --crate-type lib -C opt-level=3
+// build-pass
+
+pub trait Trait {
+    type Associated;
+}
+impl<T> Trait for T {
+    type Associated = T;
+}
+
+pub struct Struct<T>(<T as Trait>::Associated);
+
+pub fn foo<T>() -> Struct<T>
+where
+    T: Trait,
+{
+    bar()
+}
+
+#[inline]
+fn bar<T>() -> Struct<T> {
+    Struct(baz())
+}
+
+fn baz<T>() -> T {
+    unimplemented!()
+}