Sema: Fix existential opening for arguments to self.init/super.init delegation

Fixes rdar://problem/98404682.

Author: slavapestov

lib/Sema/CSApply.cpp

@@ -726,6 +726,8 @@ namespace {
         return inout->getSubExpr();
       } else if (auto force = dyn_cast<ForceValueExpr>(expr)) {
         return force->getSubExpr();
+      } else if (auto rebind = dyn_cast<RebindSelfInConstructorExpr>(expr)) {
+        return rebind->getSubExpr();
       } else {
         return nullptr;
       }
@@ -817,11 +819,6 @@ namespace {
       unsigned maxArgCount = member->getNumCurryLevels();
       unsigned depth = ExprStack.size() - getArgCount(maxArgCount);
 
-      // Invalid case -- direct call of a metatype. Has one less argument
-      // application because there's no ".init".
-      if (isa<ApplyExpr>(ExprStack.back()))
-        depth++;
-
       // Create the opaque opened value. If we started with a
       // metatype, it's a metatype.
       Type opaqueType = archetype;
@@ -3757,7 +3754,12 @@ namespace {
         expr->setSubExpr(newSubExpr);
       }
 
-      return expr;
+      // We might have opened existentials in the argument list of the
+      // constructor call.
+      Expr *result = expr;
+      closeExistentials(result, cs.getConstraintLocator(expr));
+
+      return result;
     }
 
     Expr *visitIfExpr(IfExpr *expr) {

lib/Sema/MiscDiagnostics.cpp

@@ -109,14 +109,16 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
     SmallPtrSet<DeclRefExpr*, 4> AlreadyDiagnosedBitCasts;
 
     bool IsExprStmt;
+    unsigned ExprNestingDepth;
     bool HasReachedSemanticsProvidingExpr;
 
     ASTContext &Ctx;
     const DeclContext *DC;
 
   public:
     DiagnoseWalker(const DeclContext *DC, bool isExprStmt)
-        : IsExprStmt(isExprStmt), HasReachedSemanticsProvidingExpr(false),
+        : IsExprStmt(isExprStmt), ExprNestingDepth(0),
+          HasReachedSemanticsProvidingExpr(false),
           Ctx(DC->getASTContext()), DC(DC) {}
 
     std::pair<bool, Pattern*> walkToPatternPre(Pattern *P) override {
@@ -130,6 +132,10 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
     bool shouldWalkIntoTapExpression() override { return false; }
 
     std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
+      if (isa<OpenExistentialExpr>(E)) {
+        // Don't increase ExprNestingDepth.
+        return { true, E };
+      }
 
       if (auto collection = dyn_cast<CollectionExpr>(E)) {
         if (collection->isTypeDefaulted()) {
@@ -275,9 +281,11 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
       }
 
       // Diagnose 'self.init' or 'super.init' nested in another expression
-      // or closure.
+      // or closure. The ExprNestingDepth thing is to allow this to be nested
+      // inside of an OpenExistentialExpr that is at the top level.
       if (auto *rebindSelfExpr = dyn_cast<RebindSelfInConstructorExpr>(E)) {
-        if (!Parent.isNull() || !IsExprStmt || DC->getParent()->isLocalContext()) {
+        if (ExprNestingDepth > 0 || !IsExprStmt ||
+            DC->getParent()->isLocalContext()) {
           bool isChainToSuper;
           (void)rebindSelfExpr->getCalledConstructor(isChainToSuper);
           Ctx.Diags.diagnose(E->getLoc(), diag::init_delegation_nested,
@@ -346,9 +354,20 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         HasReachedSemanticsProvidingExpr = true;
       }
 
+      ++ExprNestingDepth;
+
       return { true, E };
     }
 
+    Expr *walkToExprPost(Expr *E) override {
+      if (isa<OpenExistentialExpr>(E))
+        return E;
+
+      assert(ExprNestingDepth != 0);
+      --ExprNestingDepth;
+      return E;
+    }
+
     /// Visit each component of the keypath and emit a diagnostic if they
     /// refer to a member that has effects.
     void checkForEffectfulKeyPath(KeyPathExpr *keyPath) {
@@ -1500,6 +1519,7 @@ static void diagRecursivePropertyAccess(const Expr *E, const DeclContext *DC) {
   };
 
   DiagnoseWalker walker(var, fn);
+
   const_cast<Expr *>(E)->walk(walker);
 }
 

test/SILGen/opened_existential_in_init_delegation.swift

@@ -0,0 +1,16 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+protocol P {}
+class C {
+  init(x: some P) {}
+
+  convenience init(y: any P) { self.init(x: y) }
+}
+
+// CHECK-LABEL: sil hidden [ossa] @$s37opened_existential_in_init_delegation1CC1yAcA1P_p_tcfC : $@convention(method) (@in any P, @thick C.Type) -> @owned C {
+// CHECK: [[OPENED:%.*]] = open_existential_addr immutable_access %0 : $*any P to $*@opened("{{.*}}", any P) Self
+// CHECK: [[COPIED:%.*]] = alloc_stack $@opened("{{.*}}", any P) Self
+// CHECK: copy_addr [[OPENED]] to [initialization] [[COPIED]] : $*@opened("{{.*}}", any P) Self
+// CHECK: [[FN:%.*]] = class_method %1 : $@thick C.Type, #C.init!allocator :  (C.Type) -> (some P) -> C, $@convention(method) <τ_0_0 where τ_0_0 : P> (@in τ_0_0, @thick C.Type) -> @owned C
+// CHECK: apply [[FN]]<@opened("{{.*}}", any P) Self>([[COPIED]], %1) : $@convention(method) <τ_0_0 where τ_0_0 : P> (@in τ_0_0, @thick C.Type) -> @owned C
+// CHECK: dealloc_stack [[COPIED]] : $*@opened("{{.*}}", any P) Self