Auto merge of rust-lang#111248 - Dylan-DPC:rollup-lbp0ui3, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - rust-lang#103056 (Fix `checked_{add,sub}_duration` incorrectly returning `None` when `other` has more than `i64::MAX` seconds)
 - rust-lang#108801 (Implement RFC 3348, `c"foo"` literals)
 - rust-lang#110773 (Reduce MIR dump file count for MIR-opt tests)
 - rust-lang#110876 (Added default target cpu to `--print target-cpus` output and updated docs)
 - rust-lang#111068 (Improve check-cfg implementation)
 - rust-lang#111238 (btree_map: `Cursor{,Mut}::peek_prev` must agree)

Failed merges:

 - rust-lang#110694 (Implement builtin # syntax and use it for offset_of!(...))

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_ast/src/ast.rs

@@ -1821,6 +1821,8 @@ pub enum LitKind {
     /// A byte string (`b"foo"`). Not stored as a symbol because it might be
     /// non-utf8, and symbols only allow utf8 strings.
     ByteStr(Lrc<[u8]>, StrStyle),
+    /// A C String (`c"foo"`). Guaranteed to only have `\0` at the end.
+    CStr(Lrc<[u8]>, StrStyle),
     /// A byte char (`b'f'`).
     Byte(u8),
     /// A character literal (`'a'`).
@@ -1875,6 +1877,7 @@ impl LitKind {
             // unsuffixed variants
             LitKind::Str(..)
             | LitKind::ByteStr(..)
+            | LitKind::CStr(..)
             | LitKind::Byte(..)
             | LitKind::Char(..)
             | LitKind::Int(_, LitIntType::Unsuffixed)

compiler/rustc_ast/src/token.rs

@@ -74,6 +74,8 @@ pub enum LitKind {
     StrRaw(u8), // raw string delimited by `n` hash symbols
     ByteStr,
     ByteStrRaw(u8), // raw byte string delimited by `n` hash symbols
+    CStr,
+    CStrRaw(u8),
     Err,
 }
 
@@ -141,6 +143,10 @@ impl fmt::Display for Lit {
                 delim = "#".repeat(n as usize),
                 string = symbol
             )?,
+            CStr => write!(f, "c\"{symbol}\"")?,
+            CStrRaw(n) => {
+                write!(f, "cr{delim}\"{symbol}\"{delim}", delim = "#".repeat(n as usize))?
+            }
             Integer | Float | Bool | Err => write!(f, "{symbol}")?,
         }
 
@@ -170,6 +176,7 @@ impl LitKind {
             Float => "float",
             Str | StrRaw(..) => "string",
             ByteStr | ByteStrRaw(..) => "byte string",
+            CStr | CStrRaw(..) => "C string",
             Err => "error",
         }
     }