From 7740f7905fdebebdbe22011787d432b385f4cd9d Mon Sep 17 00:00:00 2001 From: kaizhangNV <149626564+kaizhangNV@users.noreply.github.com> Date: Tue, 23 Sep 2025 10:12:09 -0500 Subject: fix a crash when using type equality constaint (#8515) Close #8193. When constructing `TransitiveTypeWitness` node, we should check if there is operand that represents two equal times. Currently, we only check whether the operand is `TypeEqualityWitness`, which is not good enough, because a `DeclaredSubtypeWitness` could also be representing two same types, in that case, we should also const fold this kind of witness. Fails to do so, we could finally ends up with a generating a lookup witness IR on a generic parameter that is not supposed to be looked up. --- source/slang/slang-ast-builder.cpp | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'source/slang/slang-ast-builder.cpp') diff --git a/source/slang/slang-ast-builder.cpp b/source/slang/slang-ast-builder.cpp index f7304f308..be71fc334 100644 --- a/source/slang/slang-ast-builder.cpp +++ b/source/slang/slang-ast-builder.cpp @@ -936,6 +936,11 @@ top: { return bIsSubtypeOfCWitness; } + else if (auto declAIsSubtypeOfBWitness = as(aIsSubtypeOfBWitness)) + { + if (declAIsSubtypeOfBWitness->isEquality()) + return bIsSubtypeOfCWitness; + } // Similarly, if `b == c`, then the `a <: b` witness is a witness for `a <: c` // @@ -943,6 +948,11 @@ top: { return aIsSubtypeOfBWitness; } + else if (auto declBIsSubtypeOfCWitness = as(bIsSubtypeOfCWitness)) + { + if (declBIsSubtypeOfCWitness->isEquality()) + return declBIsSubtypeOfCWitness; + } // HACK: There is downstream code generation logic that assumes that // a `TransitiveSubtypeWitness` will never have a transitive witness -- cgit v1.2.3