Merge pull request swiftlang#38151 from eeckstein/fix-silgen-keypath-crash-5.5

[5.5] Revert "SILGen: avoid reusing the same opened archetype in keypath setter and getter functions."

Author: tkremenek

lib/SILGen/SILGenExpr.cpp

@@ -3521,14 +3521,6 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
     return storage->isSettable(storage->getDeclContext());
   };
 
-  // We cannot use the same opened archetype in the getter and setter. Therefore
-  // we create a new one for both the getter and the setter.
-  auto renewOpenedArchetypes = [](SubstitutableType *type) -> Type {
-    if (auto *openedTy = dyn_cast<OpenedArchetypeType>(type))
-      return OpenedArchetypeType::get(openedTy->getOpenedExistentialType());
-    return type;
-  };
-
   if (auto var = dyn_cast<VarDecl>(storage)) {
     CanType componentTy;
     if (!var->getDeclContext()->isTypeContext()) {
@@ -3552,15 +3544,13 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
     auto id = getIdForKeyPathComponentComputedProperty(*this, var,
                                                        strategy);
     auto getter = getOrCreateKeyPathGetter(*this, loc,
-             var, subs.subst(renewOpenedArchetypes,
-                             MakeAbstractConformanceForGenericType()),
+             var, subs,
              needsGenericContext ? genericEnv : nullptr,
              expansion, {}, baseTy, componentTy);
 
     if (isSettableInComponent()) {
       auto setter = getOrCreateKeyPathSetter(*this, loc,
-             var, subs.subst(renewOpenedArchetypes,
-                             MakeAbstractConformanceForGenericType()),
+             var, subs,
              needsGenericContext ? genericEnv : nullptr,
              expansion, {}, baseTy, componentTy);
       return KeyPathPatternComponent::forComputedSettableProperty(id,
@@ -3605,8 +3595,7 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
 
     auto id = getIdForKeyPathComponentComputedProperty(*this, decl, strategy);
     auto getter = getOrCreateKeyPathGetter(*this, loc,
-             decl, subs.subst(renewOpenedArchetypes,
-                              MakeAbstractConformanceForGenericType()),
+             decl, subs,
              needsGenericContext ? genericEnv : nullptr,
              expansion,
              indexTypes,
@@ -3615,8 +3604,7 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
     auto indexPatternsCopy = getASTContext().AllocateCopy(indexPatterns);
     if (isSettableInComponent()) {
       auto setter = getOrCreateKeyPathSetter(*this, loc,
-             decl, subs.subst(renewOpenedArchetypes,
-                              MakeAbstractConformanceForGenericType()),
+             decl, subs,
              needsGenericContext ? genericEnv : nullptr,
              expansion,
              indexTypes,