Merge pull request #25937 from hamishknight/all-the-sugar

Author: swift-ci

lib/AST/Type.cpp

@@ -1233,16 +1233,23 @@ CanType TypeBase::getCanonicalType(GenericSignature *sig) {
 }
 
 TypeBase *TypeBase::reconstituteSugar(bool Recursive) {
-  auto Func = [](Type Ty) -> Type {
+  auto Func = [Recursive](Type Ty) -> Type {
     if (auto boundGeneric = dyn_cast<BoundGenericType>(Ty.getPointer())) {
+
+      auto getGenericArg = [&](unsigned i) -> Type {
+        auto arg = boundGeneric->getGenericArgs()[i];
+        if (Recursive)
+          arg = arg->reconstituteSugar(Recursive);
+        return arg;
+      };
+
       auto &ctx = boundGeneric->getASTContext();
       if (boundGeneric->getDecl() == ctx.getArrayDecl())
-        return ArraySliceType::get(boundGeneric->getGenericArgs()[0]);
+        return ArraySliceType::get(getGenericArg(0));
       if (boundGeneric->getDecl() == ctx.getDictionaryDecl())
-        return DictionaryType::get(boundGeneric->getGenericArgs()[0],
-                                   boundGeneric->getGenericArgs()[1]);
+        return DictionaryType::get(getGenericArg(0), getGenericArg(1));
       if (boundGeneric->getDecl() == ctx.getOptionalDecl())
-        return OptionalType::get(boundGeneric->getGenericArgs()[0]);
+        return OptionalType::get(getGenericArg(0));
     }
     return Ty;
   };

test/Constraints/fixes.swift

@@ -261,6 +261,8 @@ struct FooStruct {
   }
 
   let e: BarStruct? = BarStruct()
+
+  func f() -> Optional<Optional<Int>> { return 29 }
 }
 
 struct BarStruct {
@@ -290,6 +292,9 @@ let _: Int = thing?.e?.a() // expected-error {{value of optional type 'Int?' mus
 let _: Int? = thing?.e?.b // expected-error {{value of optional type 'Int??' must be unwrapped to a value of type 'Int?'}}
 // expected-note@-1{{coalesce}}
 // expected-note@-2{{force-unwrap}}
+let _: Int? = thing?.f() // expected-error {{value of optional type 'Int??' must be unwrapped to a value of type 'Int?'}}
+// expected-note@-1{{coalesce}}
+// expected-note@-2{{force-unwrap}}
 
 // SR-9851 - https://bugs.swift.org/browse/SR-9851
 func coalesceWithParensRootExprFix() {