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Rollup merge of #112401 - WaffleLapkin:dont_compile_error, r=Nilstrieb
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Don't `use compile_error as print`

I've spent **1.5 hours** debugging this while trying to compile #112400, if we use `compile_error!`, we should not just forward user input to it, but issue a reasonable error message.

The better solution would be to use a lint like `clippy::print_stdout`, but since we don't have clippy in CI, let's at least make the macro error better.

Also note that some functions called here actually do use `println` (see for example `print_type_sizes` function).
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GuillaumeGomez committed Jun 8, 2023
2 parents b3d1a83 + fbe3a47 commit cf5e0b0
Showing 1 changed file with 8 additions and 1 deletion.
9 changes: 8 additions & 1 deletion compiler/rustc_driver_impl/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -58,11 +58,18 @@ use std::str;
use std::sync::OnceLock;
use std::time::Instant;

#[allow(unused_macros)]
macro do_not_use_print($($t:tt)*) {
std::compile_error!(
"Don't use `print` or `println` here, use `safe_print` or `safe_println` instead"
)
}

// This import blocks the use of panicking `print` and `println` in all the code
// below. Please use `safe_print` and `safe_println` to avoid ICE when
// encountering an I/O error during print.
#[allow(unused_imports)]
use std::{compile_error as print, compile_error as println};
use {do_not_use_print as print, do_not_use_print as println};

pub mod args;
pub mod pretty;
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