Parse the format string for the panic_fmt lint for better warnings.
This commit is contained in:
Mara Bos
parent
0f193d1a62
commit
6b44662669
@ -3831,6 +3831,7 @@ dependencies = [
|
||||
"rustc_hir",
|
||||
"rustc_index",
|
||||
"rustc_middle",
|
||||
"rustc_parse_format",
|
||||
"rustc_session",
|
||||
"rustc_span",
|
||||
"rustc_target",
|
||||
|
||||
@ -20,3 +20,4 @@ rustc_feature = { path = "../rustc_feature" }
|
||||
rustc_index = { path = "../rustc_index" }
|
||||
rustc_session = { path = "../rustc_session" }
|
||||
rustc_trait_selection = { path = "../rustc_trait_selection" }
|
||||
rustc_parse_format = { path = "../rustc_parse_format" }
|
||||
|
||||
@ -3,6 +3,7 @@
|
||||
use rustc_errors::Applicability;
|
||||
use rustc_hir as hir;
|
||||
use rustc_middle::ty;
|
||||
use rustc_parse_format::{ParseMode, Parser, Piece};
|
||||
use rustc_span::sym;
|
||||
|
||||
declare_lint! {
|
||||
@ -52,13 +53,28 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
|
||||
if cx.tcx.is_diagnostic_item(sym::std_panic_macro, id)
|
||||
|| cx.tcx.is_diagnostic_item(sym::core_panic_macro, id)
|
||||
{
|
||||
let s = sym.as_str();
|
||||
if !s.contains(&['{', '}'][..]) {
|
||||
let fmt = sym.as_str();
|
||||
if !fmt.contains(&['{', '}'][..]) {
|
||||
return;
|
||||
}
|
||||
let s = s.replace("{{", "").replace("}}", "");
|
||||
let looks_like_placeholder =
|
||||
s.find('{').map_or(false, |i| s[i + 1..].contains('}'));
|
||||
|
||||
let fmt_span = arg.span.source_callsite();
|
||||
|
||||
let (snippet, style) =
|
||||
match cx.sess().parse_sess.source_map().span_to_snippet(fmt_span) {
|
||||
Ok(snippet) => {
|
||||
// Count the number of `#`s between the `r` and `"`.
|
||||
let style = snippet.strip_prefix('r').and_then(|s| s.find('"'));
|
||||
(Some(snippet), style)
|
||||
}
|
||||
Err(_) => (None, None),
|
||||
};
|
||||
|
||||
let mut fmt_parser =
|
||||
Parser::new(fmt.as_ref(), style, snippet, false, ParseMode::Format);
|
||||
let n_arguments =
|
||||
(&mut fmt_parser).filter(|a| matches!(a, Piece::NextArgument(_))).count();
|
||||
|
||||
// Unwrap another level of macro expansion if this panic!()
|
||||
// was expanded from assert!() or debug_assert!().
|
||||
for &assert in &[sym::assert_macro, sym::debug_assert_macro] {
|
||||
@ -70,15 +86,23 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
|
||||
expn = parent;
|
||||
}
|
||||
}
|
||||
if looks_like_placeholder {
|
||||
cx.struct_span_lint(PANIC_FMT, arg.span.source_callsite(), |lint| {
|
||||
let mut l = lint.build("panic message contains an unused formatting placeholder");
|
||||
|
||||
if n_arguments > 0 && fmt_parser.errors.is_empty() {
|
||||
let arg_spans: Vec<_> = match &fmt_parser.arg_places[..] {
|
||||
[] => vec![fmt_span],
|
||||
v => v.iter().map(|span| fmt_span.from_inner(*span)).collect(),
|
||||
};
|
||||
cx.struct_span_lint(PANIC_FMT, arg_spans, |lint| {
|
||||
let mut l = lint.build(match n_arguments {
|
||||
1 => "panic message contains an unused formatting placeholder",
|
||||
_ => "panic message contains unused formatting placeholders",
|
||||
});
|
||||
l.note("this message is not used as a format string when given without arguments, but will be in a future Rust version");
|
||||
if expn.call_site.contains(arg.span) {
|
||||
l.span_suggestion(
|
||||
arg.span.shrink_to_hi(),
|
||||
"add the missing argument(s)",
|
||||
", argument".into(),
|
||||
", ...".into(),
|
||||
Applicability::HasPlaceholders,
|
||||
);
|
||||
l.span_suggestion(
|
||||
|
||||
@ -5,6 +5,6 @@ fn main() {
|
||||
panic!("here's a brace: {"); //~ WARN panic message contains a brace
|
||||
std::panic!("another one: }"); //~ WARN panic message contains a brace
|
||||
core::panic!("Hello {}"); //~ WARN panic message contains an unused formatting placeholder
|
||||
assert!(false, "{:03x} bla"); //~ WARN panic message contains an unused formatting placeholder
|
||||
assert!(false, "{:03x} {test} bla"); //~ WARN panic message contains unused formatting placeholders
|
||||
debug_assert!(false, "{{}} bla"); //~ WARN panic message contains a brace
|
||||
}
|
||||
|
||||
@ -24,35 +24,35 @@ LL | std::panic!("{}", "another one: }");
|
||||
| ^^^^^
|
||||
|
||||
warning: panic message contains an unused formatting placeholder
|
||||
--> $DIR/panic-brace.rs:7:18
|
||||
--> $DIR/panic-brace.rs:7:25
|
||||
|
|
||||
LL | core::panic!("Hello {}");
|
||||
| ^^^^^^^^^^
|
||||
| ^^
|
||||
|
|
||||
= note: this message is not used as a format string when given without arguments, but will be in a future Rust version
|
||||
help: add the missing argument(s)
|
||||
|
|
||||
LL | core::panic!("Hello {}", argument);
|
||||
| ^^^^^^^^^^
|
||||
LL | core::panic!("Hello {}", ...);
|
||||
| ^^^^^
|
||||
help: or add a "{}" format string to use the message literally
|
||||
|
|
||||
LL | core::panic!("{}", "Hello {}");
|
||||
| ^^^^^
|
||||
|
||||
warning: panic message contains an unused formatting placeholder
|
||||
--> $DIR/panic-brace.rs:8:20
|
||||
warning: panic message contains unused formatting placeholders
|
||||
--> $DIR/panic-brace.rs:8:21
|
||||
|
|
||||
LL | assert!(false, "{:03x} bla");
|
||||
| ^^^^^^^^^^^^
|
||||
LL | assert!(false, "{:03x} {test} bla");
|
||||
| ^^^^^^ ^^^^^^
|
||||
|
|
||||
= note: this message is not used as a format string when given without arguments, but will be in a future Rust version
|
||||
help: add the missing argument(s)
|
||||
|
|
||||
LL | assert!(false, "{:03x} bla", argument);
|
||||
| ^^^^^^^^^^
|
||||
LL | assert!(false, "{:03x} {test} bla", ...);
|
||||
| ^^^^^
|
||||
help: or add a "{}" format string to use the message literally
|
||||
|
|
||||
LL | assert!(false, "{}", "{:03x} bla");
|
||||
LL | assert!(false, "{}", "{:03x} {test} bla");
|
||||
| ^^^^^
|
||||
|
||||
warning: panic message contains a brace
|
||||
|
||||
Loading…
Reference in New Issue
Block a user