diff options
Diffstat (limited to 'src/ir')
| -rw-r--r-- | src/ir/gc-type-utils.h | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/src/ir/gc-type-utils.h b/src/ir/gc-type-utils.h index 6dbb3157a..2d3783591 100644 --- a/src/ir/gc-type-utils.h +++ b/src/ir/gc-type-utils.h @@ -85,16 +85,17 @@ inline EvaluationResult evaluateCastCheck(Type refType, Type castType) { return SuccessOnlyIfNull; } - // The cast will not definitely succeed nor will it definitely fail. - // - // Perhaps the heap type part of the cast can be reasoned about, at least. - // E.g. if the heap type part of the cast is definitely compatible, but the - // cast as a whole is not, that would leave only nullability as an issue, - // that is, this means that the input ref is nullable but we are casting to - // non-null. + // If the heap type part of the cast is compatible but the cast as a whole is + // not, we must have a nullable input ref that we are casting to a + // non-nullable type. if (refIsHeapSubType) { assert(refType.isNullable()); assert(castType.isNonNullable()); + if (refHeapType.isBottom()) { + // Non-null references to bottom types do not exist, so there's no value + // that could make the cast succeed. + return Failure; + } return SuccessOnlyIfNonNull; } |