diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
index e98297b692c92..bfe37ce6959e7 100644
--- a/compiler/rustc_lint/src/non_fmt_panic.rs
+++ b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -69,23 +69,65 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
let (span, panic) = panic_call(cx, f);
- cx.struct_span_lint(NON_FMT_PANIC, arg.span, |lint| {
+ // Find the span of the argument to `panic!()`, before expansion in the
+ // case of `panic!(some_macro!())`.
+ // We don't use source_callsite(), because this `panic!(..)` might itself
+ // be expanded from another macro, in which case we want to stop at that
+ // expansion.
+ let mut arg_span = arg.span;
+ let mut arg_macro = None;
+ while !span.contains(arg_span) {
+ let expn = arg_span.ctxt().outer_expn_data();
+ if expn.is_root() {
+ break;
+ }
+ arg_macro = expn.macro_def_id;
+ arg_span = expn.call_site;
+ }
+
+ cx.struct_span_lint(NON_FMT_PANIC, arg_span, |lint| {
let mut l = lint.build("panic message is not a string literal");
l.note("this is no longer accepted in Rust 2021");
- if span.contains(arg.span) {
+ if !span.contains(arg_span) {
+ // No clue where this argument is coming from.
+ l.emit();
+ return;
+ }
+ if arg_macro.map_or(false, |id| cx.tcx.is_diagnostic_item(sym::format_macro, id)) {
+ // A case of `panic!(format!(..))`.
+ l.note("the panic!() macro supports formatting, so there's no need for the format!() macro here");
+ if let Some((open, close, _)) = find_delimiters(cx, arg_span) {
+ l.multipart_suggestion(
+ "remove the `format!(..)` macro call",
+ vec![
+ (arg_span.until(open.shrink_to_hi()), "".into()),
+ (close.until(arg_span.shrink_to_hi()), "".into()),
+ ],
+ Applicability::MachineApplicable,
+ );
+ }
+ } else {
l.span_suggestion_verbose(
- arg.span.shrink_to_lo(),
+ arg_span.shrink_to_lo(),
"add a \"{}\" format string to Display the message",
"\"{}\", ".into(),
Applicability::MaybeIncorrect,
);
if panic == sym::std_panic_macro {
- l.span_suggestion_verbose(
- span.until(arg.span),
- "or use std::panic::panic_any instead",
- "std::panic::panic_any(".into(),
- Applicability::MachineApplicable,
- );
+ if let Some((open, close, del)) = find_delimiters(cx, span) {
+ l.multipart_suggestion(
+ "or use std::panic::panic_any instead",
+ if del == '(' {
+ vec![(span.until(open), "std::panic::panic_any".into())]
+ } else {
+ vec![
+ (span.until(open.shrink_to_hi()), "std::panic::panic_any(".into()),
+ (close, ")".into()),
+ ]
+ },
+ Applicability::MachineApplicable,
+ );
+ }
}
}
l.emit();
@@ -175,6 +217,19 @@ fn check_panic_str<'tcx>(
}
}
+/// Given the span of `some_macro!(args);`, gives the span of `(` and `)`,
+/// and the type of (opening) delimiter used.
+fn find_delimiters<'tcx>(cx: &LateContext<'tcx>, span: Span) -> Option<(Span, Span, char)> {
+ let snippet = cx.sess().parse_sess.source_map().span_to_snippet(span).ok()?;
+ let (open, open_ch) = snippet.char_indices().find(|&(_, c)| "([{".contains(c))?;
+ let close = snippet.rfind(|c| ")]}".contains(c))?;
+ Some((
+ span.from_inner(InnerSpan { start: open, end: open + 1 }),
+ span.from_inner(InnerSpan { start: close, end: close + 1 }),
+ open_ch,
+ ))
+}
+
fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span, Symbol) {
let mut expn = f.span.ctxt().outer_expn_data();
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 20e4f7262acb9..831e82559adcc 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -554,6 +554,7 @@ symbols! {
format_args,
format_args_capture,
format_args_nl,
+ format_macro,
freeze,
freg,
frem_fast,
diff --git a/library/alloc/src/macros.rs b/library/alloc/src/macros.rs
index a64a8b32ad77f..6a64587a2237f 100644
--- a/library/alloc/src/macros.rs
+++ b/library/alloc/src/macros.rs
@@ -107,6 +107,7 @@ macro_rules! vec {
/// ```
#[macro_export]
#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "format_macro")]
macro_rules! format {
($($arg:tt)*) => {{
let res = $crate::fmt::format($crate::__export::format_args!($($arg)*));
diff --git a/src/test/ui/non-fmt-panic.rs b/src/test/ui/non-fmt-panic.rs
index 25c53316e1290..c80a90b3eaaac 100644
--- a/src/test/ui/non-fmt-panic.rs
+++ b/src/test/ui/non-fmt-panic.rs
@@ -29,6 +29,17 @@ fn main() {
fancy_panic::fancy_panic!(S);
//~^ WARN panic message is not a string literal
+ macro_rules! a {
+ () => { 123 };
+ }
+
+ panic!(a!()); //~ WARN panic message is not a string literal
+
+ panic!(format!("{}", 1)); //~ WARN panic message is not a string literal
+
+ panic![123]; //~ WARN panic message is not a string literal
+ panic!{123}; //~ WARN panic message is not a string literal
+
// Check that the lint only triggers for std::panic and core::panic,
// not any panic macro:
macro_rules! panic {
diff --git a/src/test/ui/non-fmt-panic.stderr b/src/test/ui/non-fmt-panic.stderr
index 45187c518c423..7a333b3e76abe 100644
--- a/src/test/ui/non-fmt-panic.stderr
+++ b/src/test/ui/non-fmt-panic.stderr
@@ -93,7 +93,7 @@ LL | panic!("{}", C);
help: or use std::panic::panic_any instead
|
LL | std::panic::panic_any(C);
- | ^^^^^^^^^^^^^^^^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^
warning: panic message is not a string literal
--> $DIR/non-fmt-panic.rs:20:12
@@ -109,7 +109,7 @@ LL | panic!("{}", S);
help: or use std::panic::panic_any instead
|
LL | std::panic::panic_any(S);
- | ^^^^^^^^^^^^^^^^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^
warning: panic message is not a string literal
--> $DIR/non-fmt-panic.rs:21:17
@@ -125,7 +125,7 @@ LL | std::panic!("{}", 123);
help: or use std::panic::panic_any instead
|
LL | std::panic::panic_any(123);
- | ^^^^^^^^^^^^^^^^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^
warning: panic message is not a string literal
--> $DIR/non-fmt-panic.rs:22:18
@@ -183,5 +183,66 @@ LL | fancy_panic::fancy_panic!(S);
|
= note: this is no longer accepted in Rust 2021
-warning: 14 warnings emitted
+warning: panic message is not a string literal
+ --> $DIR/non-fmt-panic.rs:36:12
+ |
+LL | panic!(a!());
+ | ^^^^
+ |
+ = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+ |
+LL | panic!("{}", a!());
+ | ^^^^^
+help: or use std::panic::panic_any instead
+ |
+LL | std::panic::panic_any(a!());
+ | ^^^^^^^^^^^^^^^^^^^^^
+
+warning: panic message is not a string literal
+ --> $DIR/non-fmt-panic.rs:38:12
+ |
+LL | panic!(format!("{}", 1));
+ | ^^^^^^^^^^^^^^^^
+ |
+ = note: this is no longer accepted in Rust 2021
+ = note: the panic!() macro supports formatting, so there's no need for the format!() macro here
+help: remove the `format!(..)` macro call
+ |
+LL | panic!("{}", 1);
+ | -- --
+
+warning: panic message is not a string literal
+ --> $DIR/non-fmt-panic.rs:40:12
+ |
+LL | panic![123];
+ | ^^^
+ |
+ = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+ |
+LL | panic!["{}", 123];
+ | ^^^^^
+help: or use std::panic::panic_any instead
+ |
+LL | std::panic::panic_any(123);
+ | ^^^^^^^^^^^^^^^^^^^^^^ ^
+
+warning: panic message is not a string literal
+ --> $DIR/non-fmt-panic.rs:41:12
+ |
+LL | panic!{123};
+ | ^^^
+ |
+ = note: this is no longer accepted in Rust 2021
+help: add a "{}" format string to Display the message
+ |
+LL | panic!{"{}", 123};
+ | ^^^^^
+help: or use std::panic::panic_any instead
+ |
+LL | std::panic::panic_any(123);
+ | ^^^^^^^^^^^^^^^^^^^^^^ ^
+
+warning: 18 warnings emitted