Move concat test to ui and unify with new test

Author: estebank

src/test/compile-fail/concat.rs

@@ -1,4 +1,4 @@
-// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -9,7 +9,14 @@
 // except according to those terms.
 
 fn main() {
-    let _ = concat!(b"abc", b"def");
-    let _ = concat!("abc", b"def", "ghi", b"jkl");
+    concat!(b'f');    // b'' concat is supported
+    concat!(b"foo");  // b"" concat is supported
+    concat!(foo);
+    //~^ ERROR: expected a literal
+    concat!(foo());
+    //~^ ERROR: expected a literal
+    concat!(b'a', b"bc", b"def");
+    concat!("abc", b"def", 'g', "hi", b"jkl");
     //~^ ERROR cannot concatenate a byte string literal with string literals
+    // `concat!()` cannot mix "" and b"" literals (it might allow it in the future)
 }

src/test/ui/byte-concat.stderr

@@ -0,0 +1,35 @@
+error: expected a literal
+  --> $DIR/concat.rs:14:13
+   |
+LL |     concat!(foo);
+   |             ^^^
+   |
+   = note: only literals (like `"foo"`, `42` and `3.14`) can be passed to `concat!()`
+
+error: expected a literal
+  --> $DIR/concat.rs:16:13
+   |
+LL |     concat!(foo());
+   |             ^^^^^
+   |
+   = note: only literals (like `"foo"`, `42` and `3.14`) can be passed to `concat!()`
+
+error: cannot concatenate a byte string literal with string literals
+  --> $DIR/concat.rs:19:20
+   |
+LL |     concat!("abc", b"def", 'g', "hi", b"jkl");
+   |             -----  ^^^^^^  ---  ----  ^^^^^^ byte string literal
+   |             |      |       |    |
+   |             |      |       |    string literal
+   |             |      |       string literal
+   |             |      byte string literal
+   |             string literal
+   |
+   = help: do not mix byte string literals and string literals
+help: you can use byte string literals
+   |
+LL |     concat!(b"abc", b"def", b'g', b"hi", b"jkl");
+   |             ^               ^     ^
+
+error: aborting due to 3 previous errors
+