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Rollup merge of #45639 - LaurentMazare:master, r=petrochenkov

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Add a nicer error message for missing  in for loop, fixes #40782.

As suggested by @estebank in issue #40782, this works in the same way as #42578: if the in keyword is missing, we continue parsing the expression and if this works correctly an adapted error message is produced. Otherwise we return the old error.

A specific test case has also been added.
This is my first PR on rust-lang/rust so any feedback is very welcome.
This commit is contained in:
kennytm
2017-11-04 13:49:28 +08:00
committed by GitHub
parent ae512c4144 ed20f3b5c0
commit ea572657da
3 changed files with 30 additions and 1 deletions
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8
src/libsyntax/parse/parser.rs
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@@ -3154,7 +3154,13 @@ impl<'a> Parser<'a> {
// Parse: `for <src_pat> in <src_expr> <src_loop_block>`
let pat = self.parse_pat()?;
self.expect_keyword(keywords::In)?;
if !self.eat_keyword(keywords::In) {
let in_span = self.prev_span.between(self.span);
let mut err = self.sess.span_diagnostic
.struct_span_err(in_span, "missing `in` in `for` loop");
err.span_suggestion_short(in_span, "try adding `in` here", " in ".into());
err.emit();
}
let expr = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
let (iattrs, loop_block) = self.parse_inner_attrs_and_block()?;
attrs.extend(iattrs);