Auto merge of #54929 - csmoe:cfg_lint, r=petrochenkov

Suggest to remove prefix `b` in cfg attribute lint string

Closes #54926
r? @estebank

src/test/ui/conditional-compilation/cfg-attr-syntax-validation.rs

@@ -22,11 +22,14 @@ struct S7;
 #[cfg(a = 10)] //~ ERROR literal in `cfg` predicate value must be a string
 struct S8;
 
-macro_rules! generate_s9 {
+#[cfg(a = b"hi")]  //~ ERROR literal in `cfg` predicate value must be a string
+struct S9;
+
+macro_rules! generate_s10 {
     ($expr: expr) => {
         #[cfg(feature = $expr)] //~ ERROR `cfg` is not a well-formed meta-item
-        struct S9;
+        struct S10;
     }
 }
 
-generate_s9!(concat!("nonexistent"));
+generate_s10!(concat!("nonexistent"));

src/test/ui/conditional-compilation/cfg-attr-syntax-validation.stderr

@@ -40,21 +40,28 @@ error[E0537]: invalid predicate `a`
 LL | #[cfg(a())] //~ ERROR invalid predicate `a`
    |       ^^^
 
-error: literal in `cfg` predicate value must be a string
+error[E0565]: literal in `cfg` predicate value must be a string
   --> $DIR/cfg-attr-syntax-validation.rs:22:11
    |
 LL | #[cfg(a = 10)] //~ ERROR literal in `cfg` predicate value must be a string
    |           ^^
 
+error[E0565]: literal in `cfg` predicate value must be a string
+  --> $DIR/cfg-attr-syntax-validation.rs:25:11
+   |
+LL | #[cfg(a = b"hi")]  //~ ERROR literal in `cfg` predicate value must be a string
+   |           ^^^^^ help: consider removing the prefix: `"hi"`
+
 error: `cfg` is not a well-formed meta-item
-  --> $DIR/cfg-attr-syntax-validation.rs:27:9
+  --> $DIR/cfg-attr-syntax-validation.rs:30:9
    |
 LL |         #[cfg(feature = $expr)] //~ ERROR `cfg` is not a well-formed meta-item
    |         ^^^^^^^^^^^^^^^^^^^^^^^ help: expected syntax is: `#[cfg(/* predicate */)]`
 ...
-LL | generate_s9!(concat!("nonexistent"));
-   | ------------------------------------- in this macro invocation
+LL | generate_s10!(concat!("nonexistent"));
+   | -------------------------------------- in this macro invocation
 
-error: aborting due to 9 previous errors
+error: aborting due to 10 previous errors
 
-For more information about this error, try `rustc --explain E0537`.
+Some errors occurred: E0537, E0565.
+For more information about an error, try `rustc --explain E0537`.

src/test/ui/error-codes/E0565-1.stderr

@@ -1,4 +1,4 @@
-error[E0565]: unsupported literal
+error[E0565]: item in `deprecated` must be a key/value pair
   --> $DIR/E0565-1.rs:12:14
    |
 LL | #[deprecated("since")] //~ ERROR E0565

src/test/ui/error-codes/E0565-2.rs

@@ -0,0 +1,15 @@
+// Copyright 2018 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.
+
+// repr currently doesn't support literals
+#[deprecated(since = b"1.29", note = "hi")] //~ ERROR E0565
+struct A {  }
+
+fn main() {  }

src/test/ui/error-codes/E0565-2.stderr

@@ -0,0 +1,9 @@
+error[E0565]: literal in `deprecated` value must be a string
+  --> $DIR/E0565-2.rs:12:22
+   |
+LL | #[deprecated(since = b"1.29", note = "hi")] //~ ERROR E0565
+   |                      ^^^^^^^ help: consider removing the prefix: `"1.29"`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0565`.

src/test/ui/error-codes/E0565.stderr

@@ -1,4 +1,4 @@
-error[E0565]: unsupported literal
+error[E0565]: meta item in `repr` must be an identifier
   --> $DIR/E0565.rs:12:8
    |
 LL | #[repr("C")] //~ ERROR E0565