diff options
3 files changed, 118 insertions, 2 deletions
diff --git a/compiler/rustc_builtin_macros/src/format.rs b/compiler/rustc_builtin_macros/src/format.rs index 6415e55e0b0..ce9bda10721 100644 --- a/compiler/rustc_builtin_macros/src/format.rs +++ b/compiler/rustc_builtin_macros/src/format.rs @@ -758,8 +758,31 @@ fn report_missing_placeholders( check_foreign!(shell); } } - if !found_foreign && unused.len() == 1 { - diag.span_label(fmt_span, "formatting specifier missing"); + if !found_foreign { + if unused.len() == 1 { + diag.span_label(fmt_span, "formatting specifier missing"); + } + if used.iter().all(|used| !used) { + diag.note("format specifiers use curly braces: `{}`"); + } + + let mut suggest_fixed_fmt = format!("\"{}", &fmt_str[..fmt_str.len() - 1]); + for _ in &unused { + suggest_fixed_fmt.push_str("{}"); + } + suggest_fixed_fmt.push('"'); + + let suggest_fmt_count = if unused.len() == 1 { + "consider adding format specifier".to_string() + } else { + format!("consider adding {} format specifiers", unused.len()) + }; + diag.span_suggestion_verbose( + fmt_span, + suggest_fmt_count, + suggest_fixed_fmt, + Applicability::MaybeIncorrect, + ); } diag.emit(); diff --git a/tests/ui/suggestions/missing-format-specifiers-issue-68293.rs b/tests/ui/suggestions/missing-format-specifiers-issue-68293.rs new file mode 100644 index 00000000000..e1f8710db5a --- /dev/null +++ b/tests/ui/suggestions/missing-format-specifiers-issue-68293.rs @@ -0,0 +1,34 @@ +fn no_format_specifier_two_unused_args() { + println!("Hello", "World"); + //~^ ERROR argument never used + //~| NOTE formatting specifier missing + //~| NOTE format specifiers use curly braces: `{}` + //~| NOTE argument never used +} + +fn no_format_specifier_multiple_unused_args() { + println!("list: ", 1, 2, 3); + //~^ ERROR multiple unused formatting arguments + //~| NOTE multiple missing formatting specifiers + //~| NOTE format specifiers use curly braces: `{}` + //~| NOTE argument never used + //~| NOTE argument never used + //~| NOTE argument never used +} + +fn missing_format_specifiers_one_unused_arg() { + println!("list: {}, {}", 1, 2, 3); + //~^ ERROR argument never used + //~| NOTE formatting specifier missing + //~| NOTE argument never used +} + +fn missing_format_specifiers_multiple_unused_args() { + println!("list: {}", 1, 2, 3); + //~^ ERROR multiple unused formatting arguments + //~| NOTE multiple missing formatting specifiers + //~| NOTE argument never used + //~| NOTE argument never used +} + +fn main() { } diff --git a/tests/ui/suggestions/missing-format-specifiers-issue-68293.stderr b/tests/ui/suggestions/missing-format-specifiers-issue-68293.stderr new file mode 100644 index 00000000000..654c8b0712a --- /dev/null +++ b/tests/ui/suggestions/missing-format-specifiers-issue-68293.stderr @@ -0,0 +1,59 @@ +error: argument never used + --> $DIR/missing-format-specifiers-issue-68293.rs:2:23 + | +LL | println!("Hello", "World"); + | ------- ^^^^^^^ argument never used + | | + | formatting specifier missing + | + = note: format specifiers use curly braces: `{}` +help: consider adding format specifier + | +LL | println!("Hello{}", "World"); + | ++ + +error: multiple unused formatting arguments + --> $DIR/missing-format-specifiers-issue-68293.rs:10:24 + | +LL | println!("list: ", 1, 2, 3); + | -------- ^ ^ ^ argument never used + | | | | + | | | argument never used + | | argument never used + | multiple missing formatting specifiers + | + = note: format specifiers use curly braces: `{}` +help: consider adding 3 format specifiers + | +LL | println!("list: {}{}{}", 1, 2, 3); + | ++++++ + +error: argument never used + --> $DIR/missing-format-specifiers-issue-68293.rs:20:36 + | +LL | println!("list: {}, {}", 1, 2, 3); + | -------------- ^ argument never used + | | + | formatting specifier missing + | +help: consider adding format specifier + | +LL | println!("list: {}, {}{}", 1, 2, 3); + | ++ + +error: multiple unused formatting arguments + --> $DIR/missing-format-specifiers-issue-68293.rs:27:29 + | +LL | println!("list: {}", 1, 2, 3); + | ---------- ^ ^ argument never used + | | | + | | argument never used + | multiple missing formatting specifiers + | +help: consider adding 2 format specifiers + | +LL | println!("list: {}{}{}", 1, 2, 3); + | ++++ + +error: aborting due to 4 previous errors + |