1 files changed, 45 insertions, 0 deletions
diff --git a/src/test/ui/const-generics/min_const_generics/invalid-patterns.rs b/src/test/ui/const-generics/min_const_generics/invalid-patterns.rs
new file mode 100644
index 000000000..682e0eced
--- /dev/null
+++ b/src/test/ui/const-generics/min_const_generics/invalid-patterns.rs
@@ -0,0 +1,45 @@
+// stderr-per-bitwidth
+use std::mem::transmute;
+
+fn get_flag<const FlagSet: bool, const ShortName: char>() -> Option<char> {
+  if FlagSet {
+    Some(ShortName)
+  } else {
+    None
+  }
+}
+
+union CharRaw {
+  byte: u8,
+  character: char,
+}
+
+union BoolRaw {
+  byte: u8,
+  boolean: bool,
+}
+
+const char_raw: CharRaw = CharRaw { byte: 0xFF };
+const bool_raw: BoolRaw = BoolRaw { byte: 0x42 };
+
+fn main() {
+  // Test that basic cases don't work
+  assert!(get_flag::<true, 'c'>().is_some());
+  assert!(get_flag::<false, 'x'>().is_none());
+  get_flag::<false, 0xFF>();
+  //~^ ERROR mismatched types
+  get_flag::<7, 'c'>();
+  //~^ ERROR mismatched types
+  get_flag::<42, 0x5ad>();
+  //~^ ERROR mismatched types
+  //~| ERROR mismatched types
+
+
+  get_flag::<false, { unsafe { char_raw.character } }>();
+  //~^ ERROR it is undefined behavior
+  get_flag::<{ unsafe { bool_raw.boolean } }, 'z'>();
+  //~^ ERROR it is undefined behavior
+  get_flag::<{ unsafe { bool_raw.boolean } }, { unsafe { char_raw.character } }>();
+  //~^ ERROR it is undefined behavior
+  //~| ERROR it is undefined behavior
+}