SILGen: avoid reusing the same opened archetype in keypath setter and getter functions.

Author: eeckstein

lib/SILGen/SILGenExpr.cpp

@@ -3521,6 +3521,14 @@ 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()) {
@@ -3544,13 +3552,15 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
     auto id = getIdForKeyPathComponentComputedProperty(*this, var,
                                                        strategy);
     auto getter = getOrCreateKeyPathGetter(*this, loc,
-             var, subs,
+             var, subs.subst(renewOpenedArchetypes,
+                             MakeAbstractConformanceForGenericType()),
              needsGenericContext ? genericEnv : nullptr,
              expansion, {}, baseTy, componentTy);
 
     if (isSettableInComponent()) {
       auto setter = getOrCreateKeyPathSetter(*this, loc,
-             var, subs,
+             var, subs.subst(renewOpenedArchetypes,
+                             MakeAbstractConformanceForGenericType()),
              needsGenericContext ? genericEnv : nullptr,
              expansion, {}, baseTy, componentTy);
       return KeyPathPatternComponent::forComputedSettableProperty(id,
@@ -3595,7 +3605,8 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
 
     auto id = getIdForKeyPathComponentComputedProperty(*this, decl, strategy);
     auto getter = getOrCreateKeyPathGetter(*this, loc,
-             decl, subs,
+             decl, subs.subst(renewOpenedArchetypes,
+                              MakeAbstractConformanceForGenericType()),
              needsGenericContext ? genericEnv : nullptr,
              expansion,
              indexTypes,
@@ -3604,7 +3615,8 @@ SILGenModule::emitKeyPathComponentForDecl(SILLocation loc,
     auto indexPatternsCopy = getASTContext().AllocateCopy(indexPatterns);
     if (isSettableInComponent()) {
       auto setter = getOrCreateKeyPathSetter(*this, loc,
-             decl, subs,
+             decl, subs.subst(renewOpenedArchetypes,
+                              MakeAbstractConformanceForGenericType()),
              needsGenericContext ? genericEnv : nullptr,
              expansion,
              indexTypes,

test/stdlib/KeyPath.swift

@@ -329,12 +329,17 @@ class ABC: AB, ABCProtocol {
   var a = LifetimeTracked(1)
   var b = LifetimeTracked(2)
   var c = LifetimeTracked(3)
+  subscript(x: Int) -> Int {
+    get { return x + 27 }
+    set { }
+  }
 }
 
 protocol ABCProtocol {
   var a: LifetimeTracked { get }
   var b: LifetimeTracked { get set }
   var c: LifetimeTracked { get nonmutating set }
+  subscript(x: Int) -> Int { get set }
 }
 
 keyPath.test("dynamically-typed application") {
@@ -369,6 +374,7 @@ keyPath.test("dynamically-typed application") {
   let protoErasedPathA = \ABCProtocol.a
   let protoErasedPathB = \ABCProtocol.b
   let protoErasedPathC = \ABCProtocol.c
+  let protoErasedSubscript = \ABCProtocol[100]
 
   do {
     expectTrue(protoErasedSubject.a ===
@@ -389,6 +395,8 @@ keyPath.test("dynamically-typed application") {
     expectTrue(protoErasedSubject.c ===
                   protoErasedSubject[keyPath: protoErasedPathC])
     expectTrue(protoErasedSubject.c === newC)
+
+    expectTrue(protoErasedSubject[keyPath: protoErasedSubscript] == 127)
   }
 }