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fix match arm false positive

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This commit is contained in:
Josh Mcguigan 2020-04-10 20:14:53 -07:00
parent beb755caa2
commit d1338354ca
2 changed files with 16 additions and 12 deletions
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15
crates/ra_hir_ty/src/_match.rs
View file

@ -1315,8 +1315,9 @@ mod tests {
} }
"; ";
// Match arms with the incorrect type are filtered out. // Match statements with arms that don't match the
check_diagnostic(content); // expression pattern do not fire this diagnostic.
check_no_diagnostic(content);
} }
#[test] #[test]
@ -1330,8 +1331,9 @@ mod tests {
} }
"; ";
// Match arms with the incorrect type are filtered out. // Match statements with arms that don't match the
check_diagnostic(content); // expression pattern do not fire this diagnostic.
check_no_diagnostic(content);
} }
#[test] #[test]
@ -1344,8 +1346,9 @@ mod tests {
} }
"; ";
// Match arms with the incorrect type are filtered out. // Match statements with arms that don't match the
check_diagnostic(content); // expression pattern do not fire this diagnostic.
check_no_diagnostic(content);
} }
#[test] #[test]

13
crates/ra_hir_ty/src/expr.rs
View file

@ -163,12 +163,6 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
let mut seen = Matrix::empty(); let mut seen = Matrix::empty();
for pat in pats { for pat in pats {
// We skip any patterns whose type we cannot resolve.
//
// This could lead to false positives in this diagnostic, so
// it might be better to skip the entire diagnostic if we either
// cannot resolve a match arm or determine that the match arm has
// the wrong type.
if let Some(pat_ty) = infer.type_of_pat.get(pat) { if let Some(pat_ty) = infer.type_of_pat.get(pat) {
// We only include patterns whose type matches the type // We only include patterns whose type matches the type
// of the match expression. If we had a InvalidMatchArmPattern // of the match expression. If we had a InvalidMatchArmPattern
@ -191,8 +185,15 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
// to the matrix here. // to the matrix here.
let v = PatStack::from_pattern(pat); let v = PatStack::from_pattern(pat);
seen.push(&cx, v); seen.push(&cx, v);
continue;
} }
} }
// If we can't resolve the type of a pattern, or the pattern type doesn't
// fit the match expression, we skip this diagnostic. Skipping the entire
// diagnostic rather than just not including this match arm is preferred
// to avoid the chance of false positives.
return;
} }
match is_useful(&cx, &seen, &PatStack::from_wild()) { match is_useful(&cx, &seen, &PatStack::from_wild()) {