Merge pull request swiftlang#23485 from johnno1962/Self-fallback-followup

Exclude properties of class with type Self

Author: slavapestov

lib/Sema/TypeCheckType.cpp

@@ -1063,8 +1063,10 @@ static Type diagnoseUnknownType(TypeResolution resolution,
         AbstractFunctionDecl *methodDecl = dc->getInnermostMethodContext();
         bool declaringMethod = methodDecl &&
           methodDecl->getDeclContext() == dc->getParentForLookup();
+        bool isPropertyOfClass = insideClass &&
+          options.is(TypeResolverContext::PatternBindingDecl);
 
-        if (((!insideClass || !declaringMethod) &&
+        if (((!insideClass || !declaringMethod) && !isPropertyOfClass &&
              !options.is(TypeResolverContext::GenericRequirement)) ||
             options.is(TypeResolverContext::ExplicitCastExpr)) {
           Type SelfType = nominal->getSelfInterfaceType();

test/type/self.swift

@@ -70,6 +70,15 @@ class A<T> {
     // expected-warning@-1 {{conditional cast from 'Self' to 'Self' always succeeds}}
     // expected-warning@-2 {{conditional downcast from 'Self?' to 'A<T>' is equivalent to an implicit conversion to an optional 'A<T>'}}
   }
+  func copy() -> Self {
+    let copy = Self.init(a: 11)
+    return copy
+  }
+
+  var copied: Self { // expected-error {{'Self' is only available in a protocol or as the result of a method in a class; did you mean 'A'?}}
+    let copy = Self.init(a: 11)
+    return copy
+  }
 }
 
 class B: A<Int> {
@@ -88,6 +97,14 @@ class B: A<Int> {
   override class func y() {
     print("override \(Self.self).\(#function)")
   }
+  override func copy() -> Self {
+    let copy = super.copy() as! Self // supported
+    return copy
+  }
+  override var copied: Self { // expected-error {{'Self' is only available in a protocol or as the result of a method in a class; did you mean 'B'?}}
+    let copy = super.copied as! Self // unsupported
+    return copy
+  }
 }
 
 class C {
@@ -121,6 +138,15 @@ struct S2 {
       // expected-warning@-1 {{conditional cast from 'S2.S3<T>' to 'S2.S3<T>' always succeeds}}
     }
   }
+  func copy() -> Self {
+    let copy = Self.init()
+    return copy
+  }
+
+  var copied: Self {
+    let copy = Self.init()
+    return copy
+  }
 }
 
 extension S2 {