Repository navigation
-Z unpretty=expanded leads to invalid syntax for unicode escapes in format strings #116799
Description
I tried this code (Godbolt link):
pub fn main() {
println!("\x1B[1mHello, world!\x1B[0m");
println!("\u{1B}[1mHello, world!\u{1B}[0m");
println!("{}", "\x1B[1mHello, world!\x1B[0m");
}I expected to see this happen: When running rustc -Z unpretty=expanded, the format string literals for the first two println!s should remain valid string literals.
Instead, this happened: This code is generated:
use ::std::prelude::rust_2015::*;
extern crate std;
pub fn main() {
{
::std::io::_print(format_args!("\u{{1b}}[1mHello, world!\u{{1b}}[0m\n"));
};
{
::std::io::_print(format_args!("\u{{1b}}[1mHello, world!\u{{1b}}[0m\n"));
};
{
::std::io::_print(format_args!("{0}\n",
"\x1B[1mHello, world!\x1B[0m"));
};
}Note the double {{ and }} in the \u escapes.
The escape sequences in the last println! are correctly preserved.
This is annoying because it makes it impossible to run rustfmt on the macro-expanded source, which is helpful when trying to read macro-generated code.
Meta
rustc --version --verbose:
rustc 1.75.0-nightly (42b1224e9 2023-10-15)
binary: rustc
commit-hash: 42b1224e9eb37177f608d3f6a6f2be2ee13902e4
commit-date: 2023-10-15
host: x86_64-unknown-linux-gnu
release: 1.75.0-nightly
LLVM version: 17.0.2
Reacted by nora
Activity
Noratrieb commentedon Oct 16, 2023
I haven't looked at it, but this is probably going wrong somewhere in
compiler/rustc_ast_prettywhen printingFormatArgs.narpfel commentedon Oct 16, 2023
Looks like you’re right:
rust/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
Lines 686 to 693 in e7bdc5f
As I understand this, it duplicates curlies regardless of whether they’re part of an escape sequence.
narpfel commentedon Oct 16, 2023
@rustbot claim
Rollup merge of rust-lang#116811 - narpfel:unpretty-unicode-escape-in…
Unrolled build for rust-lang#116811