From 941615748d9000e66ff4400ae519dc60410a11f7 Mon Sep 17 00:00:00 2001 From: Josh Mcguigan Date: Tue, 7 Apr 2020 15:32:14 -0700 Subject: fix panic in match checking when tuple enum missing pattern --- crates/ra_hir_ty/src/_match.rs | 60 +++++++++++++++++++++++++++++++----------- 1 file changed, 45 insertions(+), 15 deletions(-) (limited to 'crates/ra_hir_ty/src') diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs index f29a25505..037db5cf8 100644 --- a/crates/ra_hir_ty/src/_match.rs +++ b/crates/ra_hir_ty/src/_match.rs @@ -235,7 +235,10 @@ impl From for PatIdOrWild { } #[derive(Debug, Clone, Copy, PartialEq)] -pub struct MatchCheckNotImplemented; +pub enum MatchCheckErr { + NotImplemented, + MalformedMatchArm, +} /// The return type of `is_useful` is either an indication of usefulness /// of the match arm, or an error in the case the match statement @@ -244,7 +247,7 @@ pub struct MatchCheckNotImplemented; /// /// The `std::result::Result` type is used here rather than a custom enum /// to allow the use of `?`. -pub type MatchCheckResult = Result; +pub type MatchCheckResult = Result; #[derive(Debug)] /// A row in a Matrix. @@ -335,12 +338,12 @@ impl PatStack { Expr::Literal(Literal::Bool(_)) => None, // perhaps this is actually unreachable given we have // already checked that these match arms have the appropriate type? - _ => return Err(MatchCheckNotImplemented), + _ => return Err(MatchCheckErr::NotImplemented), } } (Pat::Wild, constructor) => Some(self.expand_wildcard(cx, constructor)?), (Pat::Path(_), Constructor::Enum(constructor)) => { - // enums with no associated data become `Pat::Path` + // unit enum variants become `Pat::Path` let pat_id = self.head().as_id().expect("we know this isn't a wild"); if !enum_variant_matches(cx, pat_id, *constructor) { None @@ -348,16 +351,23 @@ impl PatStack { Some(self.to_tail()) } } - (Pat::TupleStruct { args: ref pat_ids, .. }, Constructor::Enum(constructor)) => { + (Pat::TupleStruct { args: ref pat_ids, .. }, Constructor::Enum(enum_constructor)) => { let pat_id = self.head().as_id().expect("we know this isn't a wild"); - if !enum_variant_matches(cx, pat_id, *constructor) { + if !enum_variant_matches(cx, pat_id, *enum_constructor) { None } else { + // If the enum variant matches, then we need to confirm + // that the number of patterns aligns with the expected + // number of patterns for that enum variant. + if pat_ids.len() != constructor.arity(cx)? { + return Err(MatchCheckErr::MalformedMatchArm); + } + Some(self.replace_head_with(pat_ids)) } } - (Pat::Or(_), _) => return Err(MatchCheckNotImplemented), - (_, _) => return Err(MatchCheckNotImplemented), + (Pat::Or(_), _) => return Err(MatchCheckErr::NotImplemented), + (_, _) => return Err(MatchCheckErr::NotImplemented), }; Ok(result) @@ -514,7 +524,7 @@ pub(crate) fn is_useful( return if any_useful { Ok(Usefulness::Useful) } else if found_unimplemented { - Err(MatchCheckNotImplemented) + Err(MatchCheckErr::NotImplemented) } else { Ok(Usefulness::NotUseful) }; @@ -567,7 +577,7 @@ pub(crate) fn is_useful( } if found_unimplemented { - Err(MatchCheckNotImplemented) + Err(MatchCheckErr::NotImplemented) } else { Ok(Usefulness::NotUseful) } @@ -604,7 +614,7 @@ impl Constructor { match cx.db.enum_data(e.parent).variants[e.local_id].variant_data.as_ref() { VariantData::Tuple(struct_field_data) => struct_field_data.len(), VariantData::Unit => 0, - _ => return Err(MatchCheckNotImplemented), + _ => return Err(MatchCheckErr::NotImplemented), } } }; @@ -637,20 +647,20 @@ fn pat_constructor(cx: &MatchCheckCtx, pat: PatIdOrWild) -> MatchCheckResult Some(Constructor::Tuple { arity: pats.len() }), Pat::Lit(lit_expr) => match cx.body.exprs[lit_expr] { Expr::Literal(Literal::Bool(val)) => Some(Constructor::Bool(val)), - _ => return Err(MatchCheckNotImplemented), + _ => return Err(MatchCheckErr::NotImplemented), }, Pat::TupleStruct { .. } | Pat::Path(_) => { let pat_id = pat.as_id().expect("we already know this pattern is not a wild"); let variant_id = - cx.infer.variant_resolution_for_pat(pat_id).ok_or(MatchCheckNotImplemented)?; + cx.infer.variant_resolution_for_pat(pat_id).ok_or(MatchCheckErr::NotImplemented)?; match variant_id { VariantId::EnumVariantId(enum_variant_id) => { Some(Constructor::Enum(enum_variant_id)) } - _ => return Err(MatchCheckNotImplemented), + _ => return Err(MatchCheckErr::NotImplemented), } } - _ => return Err(MatchCheckNotImplemented), + _ => return Err(MatchCheckErr::NotImplemented), }; Ok(res) @@ -1324,6 +1334,26 @@ mod tests { check_diagnostic(content); } + #[test] + fn malformed_match_arm_tuple_enum_missing_pattern() { + let content = r" + enum Either { + A, + B(u32), + } + fn test_fn() { + match Either::A { + Either::A => (), + Either::B() => (), + } + } + "; + + // We are testing to be sure we don't panic here when the match + // arm `Either::B` is missing its pattern. + check_no_diagnostic(content); + } + #[test] fn enum_not_in_scope() { let content = r" -- cgit v1.2.3