Simplify implicit cast ctors for vector & matrix. (#6408)

* Simplify implicit cast ctors for vector & matrix.

* Fix formatting.

* Fix tests.

* Fix Falcor test.

* Mark __builtin_cast as internal.

1 files changed, 52 insertions, 0 deletions

diff --git a/source/slang/slang-ast-val.cpp b/source/slang/slang-ast-val.cpp
index 9bcfd21bc..7613dbe80 100644
--- a/source/slang/slang-ast-val.cpp
+++ b/source/slang/slang-ast-val.cpp
@@ -845,6 +845,58 @@ void ExtractFromConjunctionSubtypeWitness::_toTextOverride(StringBuilder& out)
     out << ")";
 }
 
+void TypeCoercionWitness::_toTextOverride(StringBuilder& out)
+{
+    out << "TypeCoercionWitness(";
+    if (getFromType())
+        out << getFromType();
+    if (getToType())
+        out << getToType();
+    out << ")";
+}
+
+Val* TypeCoercionWitness::_substituteImplOverride(
+    ASTBuilder* astBuilder,
+    SubstitutionSet subst,
+    int* ioDiff)
+{
+    int diff = 0;
+
+    auto substDeclRef = getDeclRef().substituteImpl(astBuilder, subst, &diff);
+    auto substFrom = as<Type>(getFromType()->substituteImpl(astBuilder, subst, &diff));
+    auto substTo = as<Type>(getToType()->substituteImpl(astBuilder, subst, &diff));
+
+    if (!diff)
+        return this;
+
+    (*ioDiff)++;
+
+    TypeCoercionWitness* substValue =
+        astBuilder->getTypeCoercionWitness(substFrom, substTo, substDeclRef);
+    return substValue;
+}
+
+Val* TypeCoercionWitness::_resolveImplOverride()
+{
+    Val* resolvedDeclRef = nullptr;
+    if (getDeclRef())
+        resolvedDeclRef = getDeclRef().declRefBase->resolve();
+    if (auto resolvedVal = as<Witness>(resolvedDeclRef))
+        return resolvedVal;
+
+    auto newFrom = as<Type>(getFromType()->resolve());
+    auto newTo = as<Type>(getToType()->resolve());
+
+    auto newDeclRef = as<DeclRefBase>(resolvedDeclRef);
+    if (!newDeclRef)
+        newDeclRef = getDeclRef().declRefBase;
+    if (newFrom != getFromType() || newTo != getToType() || newDeclRef != getDeclRef())
+    {
+        return getCurrentASTBuilder()->getTypeCoercionWitness(newFrom, newTo, newDeclRef);
+    }
+    return this;
+}
+
 // UNormModifierVal
 
 void UNormModifierVal::_toTextOverride(StringBuilder& out)