Merge pull request #8497 from slavapestov/subst-fixes

Fixing some questionable uses of Type::subst()

Author: slavapestov

lib/AST/Type.cpp

@@ -3049,7 +3049,7 @@ static Type substType(Type derivedType,
     if (isa<GenericTypeParamType>(substOrig)) {
       if (options.contains(SubstFlags::UseErrorType))
         return ErrorType::get(type);
-      return Type(type);
+      return Type();
     }
 
     auto archetype = cast<ArchetypeType>(substOrig);
@@ -3065,7 +3065,7 @@ static Type substType(Type derivedType,
     if (!parent) {
       if (options.contains(SubstFlags::UseErrorType))
         return ErrorType::get(type);
-      return Type(type);
+      return Type();
     }
 
     // Substitute into the parent type.

lib/Serialization/Serialization.cpp

@@ -1394,7 +1394,7 @@ Serializer::writeConformance(ProtocolConformanceRef conformanceRef,
     auto substitutions = conf->getGenericSubstitutions();
     unsigned abbrCode = abbrCodes[SpecializedProtocolConformanceLayout::Code];
     auto type = conf->getType();
-    if (genericEnv)
+    if (genericEnv && type->hasArchetype())
       type = genericEnv->mapTypeOutOfContext(type);
     SpecializedProtocolConformanceLayout::emitRecord(Out, ScratchRecord,
                                                      abbrCode,
@@ -1412,7 +1412,7 @@ Serializer::writeConformance(ProtocolConformanceRef conformanceRef,
       = abbrCodes[InheritedProtocolConformanceLayout::Code];
 
     auto type = conf->getType();
-    if (genericEnv)
+    if (genericEnv && type->hasArchetype())
       type = genericEnv->mapTypeOutOfContext(type);
 
     InheritedProtocolConformanceLayout::emitRecord(
@@ -1451,7 +1451,7 @@ Serializer::writeSubstitutions(SubstitutionList substitutions,
 
   for (auto &sub : substitutions) {
     auto replacementType = sub.getReplacement();
-    if (genericEnv) {
+    if (genericEnv && replacementType->hasArchetype()) {
       replacementType =
         genericEnv->mapTypeOutOfContext(replacementType);
     }

validation-test/compiler_crashers/28732-type-hasarchetype-not-fully-substituted.swift renamed to validation-test/compiler_crashers_fixed/28732-type-hasarchetype-not-fully-substituted.swift

@@ -6,7 +6,7 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 // REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 {
 protocol A{
 struct A:P{