Revert the lexing of c_str_literals

Author: fmease

compiler/rustc_lexer/src/lib.rs

@@ -367,13 +367,6 @@ impl Cursor<'_> {
                 Some(|terminated| Byte { terminated }),
             ),
 
-            // c-string literal, raw c-string literal or identifier.
-            'c' => self.c_or_byte_string(
-                |terminated| CStr { terminated },
-                |n_hashes| RawCStr { n_hashes },
-                None,
-            ),
-
             // Identifier (this should be checked after other variant that can
             // start as identifier).
             c if is_id_start(c) => self.ident_or_unknown_prefix(),

tests/ui/rfcs/rfc-3348-c-string-literals/basic.rs

@@ -1,4 +1,6 @@
-// run-pass
+// FIXME(c_str_literals): This should be `run-pass`
+// known-bug: #113333
+// edition: 2021
 
 #![feature(c_str_literals)]
 

tests/ui/rfcs/rfc-3348-c-string-literals/basic.stderr

@@ -0,0 +1,25 @@
+error: prefix `c` is unknown
+  --> $DIR/basic.rs:8:27
+   |
+LL |     assert_eq!(b"test\0", c"test".to_bytes_with_nul());
+   |                           ^ unknown prefix
+   |
+   = note: prefixed identifiers and literals are reserved since Rust 2021
+help: consider inserting whitespace here
+   |
+LL |     assert_eq!(b"test\0", c "test".to_bytes_with_nul());
+   |                            +
+
+error: no rules expected the token `"test"`
+  --> $DIR/basic.rs:8:28
+   |
+LL |     assert_eq!(b"test\0", c"test".to_bytes_with_nul());
+   |                            -^^^^^
+   |                            |
+   |                            no rules expected this token in macro call
+   |                            help: missing comma here
+   |
+   = note: while trying to match sequence start
+
+error: aborting due to 2 previous errors
+

tests/ui/rfcs/rfc-3348-c-string-literals/gate.rs

@@ -1,13 +1,15 @@
 // gate-test-c_str_literals
+// known-bug: #113333
+// edition: 2021
 
 macro_rules! m {
     ($t:tt) => {}
 }
 
 fn main() {
     c"foo";
-    //~^ ERROR: `c".."` literals are experimental
+    // FIXME(c_str_literals): This should be ``c".."` literals are experimental`
 
     m!(c"test");
-    //~^ ERROR: `c".."` literals are experimental
+    // FIXME(c_str_literals): This should be ``c".."` literals are experimental`
 }

tests/ui/rfcs/rfc-3348-c-string-literals/gate.stderr

@@ -1,21 +1,32 @@
-error[E0658]: `c".."` literals are experimental
-  --> $DIR/gate.rs:8:5
+error: prefix `c` is unknown
+  --> $DIR/gate.rs:10:5
    |
 LL |     c"foo";
-   |     ^^^^^^
+   |     ^ unknown prefix
    |
-   = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
-   = help: add `#![feature(c_str_literals)]` to the crate attributes to enable
+   = note: prefixed identifiers and literals are reserved since Rust 2021
+help: consider inserting whitespace here
+   |
+LL |     c "foo";
+   |      +
 
-error[E0658]: `c".."` literals are experimental
-  --> $DIR/gate.rs:11:8
+error: prefix `c` is unknown
+  --> $DIR/gate.rs:13:8
    |
 LL |     m!(c"test");
-   |        ^^^^^^^
+   |        ^ unknown prefix
+   |
+   = note: prefixed identifiers and literals are reserved since Rust 2021
+help: consider inserting whitespace here
    |
-   = note: see issue #105723 <https://github.com/rust-lang/rust/issues/105723> for more information
-   = help: add `#![feature(c_str_literals)]` to the crate attributes to enable
+LL |     m!(c "test");
+   |         +
+
+error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `"foo"`
+  --> $DIR/gate.rs:10:6
+   |
+LL |     c"foo";
+   |      ^^^^^ expected one of 8 possible tokens
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0658`.

tests/ui/rfcs/rfc-3348-c-string-literals/no-nuls.rs

@@ -1,4 +1,6 @@
-// run-pass
+// FIXME(c_str_literals): This should be `run-pass`
+// known-bug: #113333
+// edition: 2021
 
 #![feature(c_str_literals)]
 

tests/ui/rfcs/rfc-3348-c-string-literals/no-nuls.stderr

@@ -0,0 +1,38 @@
+error: prefix `c` is unknown
+  --> $DIR/non-ascii.rs:9:9
+   |
+LL |         c"\xEF\x80🦀\u{1F980}".to_bytes_with_nul(),
+   |         ^ unknown prefix
+   |
+   = note: prefixed identifiers and literals are reserved since Rust 2021
+help: consider inserting whitespace here
+   |
+LL |         c "\xEF\x80🦀\u{1F980}".to_bytes_with_nul(),
+   |          +
+
+error: out of range hex escape
+  --> $DIR/non-ascii.rs:9:11
+   |
+LL |         c"\xEF\x80🦀\u{1F980}".to_bytes_with_nul(),
+   |           ^^^^ must be a character in the range [\x00-\x7f]
+
+error: out of range hex escape
+  --> $DIR/non-ascii.rs:9:15
+   |
+LL |         c"\xEF\x80🦀\u{1F980}".to_bytes_with_nul(),
+   |               ^^^^ must be a character in the range [\x00-\x7f]
+
+error: no rules expected the token `"\xEF\x80🦀\u{1F980}"`
+  --> $DIR/non-ascii.rs:9:10
+   |
+LL |         c"\xEF\x80🦀\u{1F980}".to_bytes_with_nul(),
+   |          -^^^^^^^^^^^^^^^^^^^^
+   |          |
+   |          no rules expected this token in macro call
+   |          help: missing comma here
+   |
+note: while trying to match `,`
+  --> $SRC_DIR/core/src/macros/mod.rs:LL:COL
+
+error: aborting due to 4 previous errors
+