Add const generics failing test for pattern types

Author: spastorino

tests/ui/type/pattern_types/const_generics.rs

@@ -0,0 +1,13 @@
+#![feature(pattern_types)]
+#![feature(core_pattern_types)]
+#![feature(core_pattern_type)]
+
+use std::pat::pattern_type;
+
+trait Foo {}
+
+impl<const START: u32, const END: u32> Foo for pattern_type!(u32 is START..=END) {}
+//~^ ERROR: range patterns must have constant range start and end
+//~| ERROR: range patterns must have constant range start and end
+
+fn main() {}

tests/ui/type/pattern_types/const_generics.stderr

@@ -0,0 +1,14 @@
+error: "range patterns must have constant range start and end"
+  --> $DIR/const_generics.rs:9:69
+   |
+LL | impl<const START: u32, const END: u32> Foo for pattern_type!(u32 is START..=END) {}
+   |                                                                     ^^^^^
+
+error: "range patterns must have constant range start and end"
+  --> $DIR/const_generics.rs:9:77
+   |
+LL | impl<const START: u32, const END: u32> Foo for pattern_type!(u32 is START..=END) {}
+   |                                                                             ^^^
+
+error: aborting due to 2 previous errors
+