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lint based on closure pipe span

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This commit is contained in:
csmoe 2018-11-15 16:35:23 +08:00
parent 4ec0ba9545
commit 052bdff8fb
2 changed files with 17 additions and 1 deletions
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16
src/librustc/traits/error_reporting.rs
View file

@ -1092,13 +1092,27 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
if let Some(found_span) = found_span {
err.span_label(found_span, format!("takes {}", found_str));
// move |_| { ... }
// ^^^^^^^^-- def_span
//
// move |_| { ... }
// ^^^^^-- prefix
let prefix_span = self.tcx.sess.source_map().span_until_char(found_span, '|');
// move |_| { ... }
// ^^^-- pipe_span
let pipe_span = if let Some(span) = found_span.trim_start(prefix_span) {
span
} else {
found_span
};
// Suggest to take and ignore the arguments with expected_args_length `_`s if
// found arguments is empty (assume the user just wants to ignore args in this case).
// For example, if `expected_args_length` is 2, suggest `|_, _|`.
if found_args.is_empty() && is_closure {
let underscores = vec!["_"; expected_args.len()].join(", ");
err.span_suggestion_with_applicability(
found_span,
pipe_span,
&format!(
"consider changing the closure to take and ignore the expected argument{}",
if expected_args.len() < 2 {

2
src/test/ui/mismatched_types/closure-arg-count.rs
View file

@ -22,6 +22,8 @@ fn main() {
//~^ ERROR closure is expected to take
f(|| panic!());
//~^ ERROR closure is expected to take
f(move || panic!());
//~^ ERROR closure is expected to take
let _it = vec![1, 2, 3].into_iter().enumerate().map(|i, x| i);
//~^ ERROR closure is expected to take