Add 67684

Issue: rust-lang/rust#67684

Author: fanninpm

ices/67684.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+rustc -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2 --crate-type lib - << 'EOF'
+trait ParseError {
+    type StreamError;
+}
+impl<T> ParseError for T {
+    type StreamError = ();
+}
+trait Stream {
+    type Error;
+}
+trait Parser
+where
+    <Self as Parser>::PartialState: Default,
+{
+    type PartialState;
+    fn parse_mode(&Self, Self::PartialState) {}
+}
+struct AndThen<A, B>(core::marker::PhantomData<(A, B)>);
+impl<A, B> Parser for AndThen<A, B>
+where
+    A: Stream,
+    B: Into<<A::Error as ParseError>::StreamError>,
+{
+    type PartialState = ();
+}
+fn expr<A>() -> impl Parser
+where
+    A: Stream,
+{
+    AndThen::<A, ()>(core::marker::PhantomData)
+}
+fn parse_mode_impl<A>()
+where
+    A::Error: ParseError,
+    A: Stream,
+{
+    Parser::parse_mode(&expr::<A>(), Default::default())
+}
+EOF