Skip to content

Commit

Permalink
Auto merge of #53256 - ollie27:writeln, r=KodrAus
Browse files Browse the repository at this point in the history
Don't accept non-string literals for the format string in writeln

This is to improve diagnostics.

`println` and `eprintln` were already fixed by #52394.

Fixes #30143
  • Loading branch information
bors committed Aug 16, 2018
2 parents b837f5b + 7b0bafe commit 5050349
Show file tree
Hide file tree
Showing 3 changed files with 56 additions and 5 deletions.
8 changes: 3 additions & 5 deletions src/libcore/macros.rs
Original file line number Diff line number Diff line change
Expand Up @@ -396,18 +396,16 @@ macro_rules! write {
/// ```
#[macro_export]
#[stable(feature = "rust1", since = "1.0.0")]
#[allow_internal_unstable]
macro_rules! writeln {
($dst:expr) => (
write!($dst, "\n")
);
($dst:expr,) => (
writeln!($dst)
);
($dst:expr, $fmt:expr) => (
write!($dst, concat!($fmt, "\n"))
);
($dst:expr, $fmt:expr, $($arg:tt)*) => (
write!($dst, concat!($fmt, "\n"), $($arg)*)
($dst:expr, $($arg:tt)*) => (
$dst.write_fmt(format_args_nl!($($arg)*))
);
}

Expand Down
21 changes: 21 additions & 0 deletions src/test/ui/macros/issue-30143.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
// 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.

use std::fmt::Write;

fn main() {
println!(0);
//~^ ERROR format argument must be a string literal
eprintln!('a');
//~^ ERROR format argument must be a string literal
let mut s = String::new();
writeln!(s, true).unwrap();
//~^ ERROR format argument must be a string literal
}
32 changes: 32 additions & 0 deletions src/test/ui/macros/issue-30143.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
error: format argument must be a string literal
--> $DIR/issue-30143.rs:14:14
|
LL | println!(0);
| ^
help: you might be missing a string literal to format with
|
LL | println!("{}", 0);
| ^^^^^

error: format argument must be a string literal
--> $DIR/issue-30143.rs:16:15
|
LL | eprintln!('a');
| ^^^
help: you might be missing a string literal to format with
|
LL | eprintln!("{}", 'a');
| ^^^^^

error: format argument must be a string literal
--> $DIR/issue-30143.rs:19:17
|
LL | writeln!(s, true).unwrap();
| ^^^^
help: you might be missing a string literal to format with
|
LL | writeln!(s, "{}", true).unwrap();
| ^^^^^

error: aborting due to 3 previous errors

0 comments on commit 5050349

Please sign in to comment.