handle mixed byte literal and byte array patterns

Convert byte literal pattern to byte array patterns when they are both
used together. so matching them is properly handled. I could've done the
conversion eagerly, but that could have caused a bad worst-case for
massive byte-array matches.

Fixes #18027.
Fixes #25051.
Fixes #26510.

1 files changed, 73 insertions, 0 deletions

diff --git a/src/test/compile-fail/match-byte-array-patterns.rs b/src/test/compile-fail/match-byte-array-patterns.rs
new file mode 100644
index 00000000000..86323656b87
--- /dev/null
+++ b/src/test/compile-fail/match-byte-array-patterns.rs
@@ -0,0 +1,73 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(advanced_slice_patterns, slice_patterns)]
+
+fn main() {
+    let buf = &[0, 1, 2, 3];
+
+    match buf {
+        b"AAAA" => {},
+        &[0x41, 0x41, 0x41, 0x41] => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf {
+        &[0x41, 0x41, 0x41, 0x41] => {}
+        b"AAAA" => {}, //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf {
+        &[_, 0x41, 0x41, 0x41] => {},
+        b"AAAA" => {}, //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf {
+        &[0x41, .., 0x41] => {}
+        b"AAAA" => {}, //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf { //~ ERROR non-exhaustive
+        b"AAAA" => {}
+    }
+
+    let buf: &[u8] = buf;
+
+    match buf {
+        b"AAAA" => {},
+        &[0x41, 0x41, 0x41, 0x41] => {} //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf {
+        &[0x41, 0x41, 0x41, 0x41] => {}
+        b"AAAA" => {}, //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf {
+        &[_, 0x41, 0x41, 0x41] => {},
+        b"AAAA" => {}, //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf {
+        &[0x41, .., 0x41] => {}
+        b"AAAA" => {}, //~ ERROR unreachable pattern
+        _ => {}
+    }
+
+    match buf { //~ ERROR non-exhaustive
+        b"AAAA" => {}
+    }
+}