user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix ICE for mismatched args on target without span

Browse source 
Commit 7ed00caacc improved our error reporting by including the target
function in our error messages when there is an argument count mismatch.
A simple example from the UI tests is:

```
error[E0593]: function is expected to take a single 2-tuple as argument, but it takes 0 arguments
  --> $DIR/closure-arg-count.rs:32:53
   |
32 |     let _it = vec![1, 2, 3].into_iter().enumerate().map(foo);
   |                                                     ^^^ expected function that takes a single 2-tuple as argument
...
44 | fn foo() {}
   | -------- takes 0 arguments
```

However, this assumed the target span was always available. This does
not hold true if the target function is in `std` or another crate. A
simple example from #48046 is assigning `str::split` to a function type
with a different number of arguments.

Fix by removing all of the labels and suggestions related to the target
span when it's not found.

Fixes #48046
This commit is contained in:
Ryan Cumming 2018-02-07 18:34:45 +11:00
parent 4f93357d3b
commit daaa9a440c
3 changed files with 60 additions and 46 deletions
Download patch file Download diff file Expand all files Collapse all files

91
src/librustc/traits/error_reporting.rs
View file

@ -744,8 +744,10 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
} else {
let (closure_span, found) = found_did
.and_then(|did| self.tcx.hir.get_if_local(did))
.map(|node| self.get_fn_like_arguments(node))
.unwrap_or((found_span.unwrap(), found));
.map(|node| {
let (found_span, found) = self.get_fn_like_arguments(node);
(Some(found_span), found)
}).unwrap_or((found_span, found));
self.report_arg_count_mismatch(span,
closure_span,
@ -855,7 +857,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
fn report_arg_count_mismatch(
&self,
span: Span,
found_span: Span,
found_span: Option<Span>,
expected_args: Vec<ArgKind>,
found_args: Vec<ArgKind>,
is_closure: bool,
@ -893,48 +895,51 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
);
err.span_label(span, format!( "expected {} that takes {}", kind, expected_str));
err.span_label(found_span, format!("takes {}", found_str));
if let &[ArgKind::Tuple(_, ref fields)] = &found_args[..] {
if fields.len() == expected_args.len() {
let sugg = fields.iter()
.map(|(name, _)| name.to_owned())
.collect::<Vec<String>>().join(", ");
err.span_suggestion(found_span,
"change the closure to take multiple arguments instead of \
a single tuple",
format!("|{}|", sugg));
if let Some(found_span) = found_span {
err.span_label(found_span, format!("takes {}", found_str));
if let &[ArgKind::Tuple(_, ref fields)] = &found_args[..] {
if fields.len() == expected_args.len() {
let sugg = fields.iter()
.map(|(name, _)| name.to_owned())
.collect::<Vec<String>>().join(", ");
err.span_suggestion(found_span,
"change the closure to take multiple arguments instead of \
a single tuple",
format!("|{}|", sugg));
}
}
}
if let &[ArgKind::Tuple(_, ref fields)] = &expected_args[..] {
if fields.len() == found_args.len() && is_closure {
let sugg = format!(
"|({}){}|",
found_args.iter()
.map(|arg| match arg {
ArgKind::Arg(name, _) => name.to_owned(),
_ => "_".to_owned(),
})
.collect::<Vec<String>>()
.join(", "),
// add type annotations if available
if found_args.iter().any(|arg| match arg {
ArgKind::Arg(_, ty) => ty != "_",
_ => false,
}) {
format!(": ({})",
fields.iter()
.map(|(_, ty)| ty.to_owned())
.collect::<Vec<String>>()
.join(", "))
} else {
"".to_owned()
},
);
err.span_suggestion(found_span,
"change the closure to accept a tuple instead of individual \
arguments",
sugg);
if let &[ArgKind::Tuple(_, ref fields)] = &expected_args[..] {
if fields.len() == found_args.len() && is_closure {
let sugg = format!(
"|({}){}|",
found_args.iter()
.map(|arg| match arg {
ArgKind::Arg(name, _) => name.to_owned(),
_ => "_".to_owned(),
})
.collect::<Vec<String>>()
.join(", "),
// add type annotations if available
if found_args.iter().any(|arg| match arg {
ArgKind::Arg(_, ty) => ty != "_",
_ => false,
}) {
format!(": ({})",
fields.iter()
.map(|(_, ty)| ty.to_owned())
.collect::<Vec<String>>()
.join(", "))
} else {
"".to_owned()
},
);
err.span_suggestion(found_span,
"change the closure to accept a tuple instead of \
individual arguments",
sugg);
}
}
}

3
src/test/ui/mismatched_types/closure-arg-count.rs
View file

@ -36,6 +36,9 @@ fn main() {
//~^ ERROR closure is expected to take
let _it = vec![1, 2, 3].into_iter().enumerate().map(qux);
//~^ ERROR function is expected to take
let _it = vec![1, 2, 3].into_iter().map(usize::checked_add);
//~^ ERROR function is expected to take
}
fn foo() {}

12
src/test/ui/mismatched_types/closure-arg-count.stderr
View file

@ -90,7 +90,7 @@ error[E0593]: function is expected to take a single 2-tuple as argument, but it
32 | let _it = vec![1, 2, 3].into_iter().enumerate().map(foo);
| ^^^ expected function that takes a single 2-tuple as argument
...
41 | fn foo() {}
44 | fn foo() {}
| -------- takes 0 arguments
error[E0593]: closure is expected to take a single 2-tuple as argument, but it takes 3 distinct arguments
@ -107,8 +107,14 @@ error[E0593]: function is expected to take a single 2-tuple as argument, but it
37 | let _it = vec![1, 2, 3].into_iter().enumerate().map(qux);
| ^^^ expected function that takes a single 2-tuple as argument
...
42 | fn qux(x: usize, y: usize) {}
45 | fn qux(x: usize, y: usize) {}
| -------------------------- takes 2 distinct arguments
error: aborting due to 11 previous errors
error[E0593]: function is expected to take 1 argument, but it takes 2 arguments
--> $DIR/closure-arg-count.rs:40:41
|
40 | let _it = vec![1, 2, 3].into_iter().map(usize::checked_add);
| ^^^ expected function that takes 1 argument
error: aborting due to 12 previous errors