Fix another related ICE

Author: oli-obk

src/librustc_mir/hair/pattern/_match.rs

@@ -1355,11 +1355,6 @@ fn slice_pat_covered_by_constructor<'tcx>(
                 ConstValue::Scalar(val) | ConstValue::ScalarPair(val, _) => val,
             };
             if let Ok(ptr) = val.to_ptr() {
-                let is_array_ptr = const_val.ty
-                    .builtin_deref(true)
-                    .and_then(|t| t.ty.builtin_index())
-                    .map_or(false, |t| t == tcx.types.u8);
-                assert!(is_array_ptr);
                 tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id).bytes.as_ref()
             } else {
                 bug!("unexpected non-ptr ConstantValue")

src/test/ui/pattern/slice-pattern-const-2.rs

@@ -6,6 +6,19 @@ fn main() {
     match s {
         MAGIC_TEST => (),
         [0x00, 0x00, 0x00, 0x00] => (),
+        [4, 5, 6, 7] => (), // this should warn
+        _ => (),
+    }
+    match s {
+        [0x00, 0x00, 0x00, 0x00] => (),
+        MAGIC_TEST => (),
+        [4, 5, 6, 7] => (), // this should warn
+        _ => (),
+    }
+    match s {
+        [0x00, 0x00, 0x00, 0x00] => (),
+        [4, 5, 6, 7] => (),
+        MAGIC_TEST => (), // this should warn
         _ => (),
     }
 }

src/test/ui/pattern/slice-pattern-const-3.rs

@@ -6,6 +6,19 @@ fn main() {
     match s {
         MAGIC_TEST => (),
         ["0x00", "0x00", "0x00", "0x00"] => (),
+        ["4", "5", "6", "7"] => (), // this should warn
+        _ => (),
+    }
+    match s {
+        ["0x00", "0x00", "0x00", "0x00"] => (),
+        MAGIC_TEST => (),
+        ["4", "5", "6", "7"] => (), // this should warn
+        _ => (),
+    }
+    match s {
+        ["0x00", "0x00", "0x00", "0x00"] => (),
+        ["4", "5", "6", "7"] => (),
+        MAGIC_TEST => (), // this should warn
         _ => (),
     }
 }

src/test/ui/pattern/slice-pattern-const.rs

@@ -1,11 +1,24 @@
-// compile-pass
+//compile-pass
 
 fn main() {
     let s = &[0x00; 4][..]; //Slice of any value
     const MAGIC_TEST: &[u8] = b"TEST"; //Const slice to pattern match with
     match s {
         MAGIC_TEST => (),
         [0x00, 0x00, 0x00, 0x00] => (),
+        [84, 69, 83, 84] => (), // this should warn
+        _ => (),
+    }
+    match s {
+        [0x00, 0x00, 0x00, 0x00] => (),
+        MAGIC_TEST => (),
+        [84, 69, 83, 84] => (), // this should warn
+        _ => (),
+    }
+    match s {
+        [0x00, 0x00, 0x00, 0x00] => (),
+        [84, 69, 83, 84] => (),
+        MAGIC_TEST => (), // this should warn
         _ => (),
     }
 }