diff --git a/compiler/rustc_builtin_macros/src/format.rs b/compiler/rustc_builtin_macros/src/format.rs index 590db12a4cd..ede95dbf897 100644 --- a/compiler/rustc_builtin_macros/src/format.rs +++ b/compiler/rustc_builtin_macros/src/format.rs @@ -1,6 +1,6 @@ use rustc_ast::ptr::P; -use rustc_ast::token; use rustc_ast::tokenstream::TokenStream; +use rustc_ast::{token, StmtKind}; use rustc_ast::{ Expr, ExprKind, FormatAlignment, FormatArgPosition, FormatArgPositionKind, FormatArgs, FormatArgsPiece, FormatArgument, FormatArgumentKind, FormatArguments, FormatCount, @@ -163,7 +163,7 @@ fn make_format_args( let MacroInput { fmtstr: efmt, mut args, is_direct_literal } = input; - let (fmt_str, fmt_style, fmt_span) = match expr_to_spanned_string(ecx, efmt, msg) { + let (fmt_str, fmt_style, fmt_span) = match expr_to_spanned_string(ecx, efmt.clone(), msg) { Ok(mut fmt) if append_newline => { fmt.0 = Symbol::intern(&format!("{}\n", fmt.0)); fmt @@ -171,17 +171,33 @@ fn make_format_args( Ok(fmt) => fmt, Err(err) => { if let Some((mut err, suggested)) = err { - let sugg_fmt = match args.explicit_args().len() { - 0 => "{}".to_string(), - _ => format!("{}{{}}", "{} ".repeat(args.explicit_args().len())), - }; if !suggested { - err.span_suggestion( - unexpanded_fmt_span.shrink_to_lo(), - "you might be missing a string literal to format with", - format!("\"{sugg_fmt}\", "), - Applicability::MaybeIncorrect, - ); + if let ExprKind::Block(block, None) = &efmt.kind + && block.stmts.len() == 1 + && let StmtKind::Expr(expr) = &block.stmts[0].kind + && let ExprKind::Path(None, path) = &expr.kind + && path.is_potential_trivial_const_arg() + { + err.multipart_suggestion( + "quote your inlined format argument to use as string literal", + vec![ + (unexpanded_fmt_span.shrink_to_hi(), "\"".to_string()), + (unexpanded_fmt_span.shrink_to_lo(), "\"".to_string()), + ], + Applicability::MaybeIncorrect, + ); + } else { + let sugg_fmt = match args.explicit_args().len() { + 0 => "{}".to_string(), + _ => format!("{}{{}}", "{} ".repeat(args.explicit_args().len())), + }; + err.span_suggestion( + unexpanded_fmt_span.shrink_to_lo(), + "you might be missing a string literal to format with", + format!("\"{sugg_fmt}\", "), + Applicability::MaybeIncorrect, + ); + } } err.emit(); } diff --git a/tests/ui/fmt/suggest-inline-args.rs b/tests/ui/fmt/suggest-inline-args.rs new file mode 100644 index 00000000000..515335ed9f4 --- /dev/null +++ b/tests/ui/fmt/suggest-inline-args.rs @@ -0,0 +1,28 @@ +mod foo { + pub fn bar() -> i32 { + 1 + } +} + +fn bar() -> i32 { + 2 +} + +fn main() { + let stderr = 3; + eprintln!({stderr}); + //~^ ERROR format argument must be a string literal + //~| HELP quote your inlined format argument to use as string literal + eprintln!({1}); + //~^ ERROR format argument must be a string literal + //~| HELP you might be missing a string literal to format with + eprintln!({foo::bar()}); + //~^ ERROR format argument must be a string literal + //~| HELP you might be missing a string literal to format with + eprintln!({bar()}); + //~^ ERROR format argument must be a string literal + //~| HELP you might be missing a string literal to format with + eprintln!({1; 2}); + //~^ ERROR format argument must be a string literal + //~| HELP you might be missing a string literal to format with +} diff --git a/tests/ui/fmt/suggest-inline-args.stderr b/tests/ui/fmt/suggest-inline-args.stderr new file mode 100644 index 00000000000..cf70568cf3f --- /dev/null +++ b/tests/ui/fmt/suggest-inline-args.stderr @@ -0,0 +1,57 @@ +error: format argument must be a string literal + --> $DIR/suggest-inline-args.rs:13:15 + | +LL | eprintln!({stderr}); + | ^^^^^^^^ + | +help: quote your inlined format argument to use as string literal + | +LL | eprintln!("{stderr}"); + | + + + +error: format argument must be a string literal + --> $DIR/suggest-inline-args.rs:16:15 + | +LL | eprintln!({1}); + | ^^^ + | +help: you might be missing a string literal to format with + | +LL | eprintln!("{}", {1}); + | +++++ + +error: format argument must be a string literal + --> $DIR/suggest-inline-args.rs:19:15 + | +LL | eprintln!({foo::bar()}); + | ^^^^^^^^^^^^ + | +help: you might be missing a string literal to format with + | +LL | eprintln!("{}", {foo::bar()}); + | +++++ + +error: format argument must be a string literal + --> $DIR/suggest-inline-args.rs:22:15 + | +LL | eprintln!({bar()}); + | ^^^^^^^ + | +help: you might be missing a string literal to format with + | +LL | eprintln!("{}", {bar()}); + | +++++ + +error: format argument must be a string literal + --> $DIR/suggest-inline-args.rs:25:15 + | +LL | eprintln!({1; 2}); + | ^^^^^^ + | +help: you might be missing a string literal to format with + | +LL | eprintln!("{}", {1; 2}); + | +++++ + +error: aborting due to 5 previous errors +