Add testcase to prove bug is fixed

This bug was fixed in commit cb4d935508def8b250345ba5205a90ad9e177ab4
with related PR #1223

The issue is that associated tpyes get updated depending on the context
they are used so we need to monomorphize the types when we can so that we
don't then throw off the rest of typechecking with bogus errors like this.

Fixes #1237

1 files changed, 23 insertions, 0 deletions

diff --git a/gcc/testsuite/rust/compile/issue-1237.rs b/gcc/testsuite/rust/compile/issue-1237.rs
new file mode 100644
index 0000000..542be89
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-1237.rs
@@ -0,0 +1,23 @@
+// { dg-additional-options "-w" }
+mod intrinsics {
+    extern "rust-intrinsic" {
+        pub fn offset<T>(ptr: *const T, count: isize) -> *const T;
+    }
+}
+
+impl<T> *const T {
+    pub unsafe fn offset(self, count: isize) -> *const T {
+        unsafe { intrinsics::offset(self, count) }
+    }
+}
+
+impl<T> [T] {
+    pub unsafe fn get_unchecked(&self, index: usize) -> &T {
+        unsafe { &*(self as *const [T] as *const T).offset(index as isize) }
+    }
+}
+
+#[inline]
+unsafe fn u8to64_le(buf: &[u8], start: usize, len: usize) -> u64 {
+    (unsafe { *buf.get_unchecked(start) } as u64)
+}