Merge pull request #75641 from slavapestov/fix-issue-74651

Sema: Fix crash with property override and almost-valid superclass

Author: slavapestov

lib/Sema/TypeCheckDeclOverride.cpp

@@ -857,19 +857,6 @@ namespace {
 
       return cachedDeclType;
     }
-
-    /// Adjust the interface of the given declaration, which is found in
-    /// a supertype of the given type.
-    Type getSuperMemberDeclType(ValueDecl *baseDecl) const {
-      auto selfType = decl->getDeclContext()->getSelfInterfaceType();
-      if (selfType->getClassOrBoundGenericClass()) {
-        selfType = selfType->getSuperclass();
-        assert(selfType && "No superclass type?");
-      }
-
-      return selfType->adjustSuperclassMemberDeclType(
-               baseDecl, decl, baseDecl->getInterfaceType());
-    }
   };
 }
 
@@ -1283,7 +1270,9 @@ bool OverrideMatcher::checkOverride(ValueDecl *baseDecl,
     }
   } else if (auto property = dyn_cast<VarDecl>(decl)) {
     auto propertyTy = property->getInterfaceType();
-    auto parentPropertyTy = getSuperMemberDeclType(baseDecl);
+    auto selfType = decl->getDeclContext()->getSelfInterfaceType();
+    auto parentPropertyTy = selfType->adjustSuperclassMemberDeclType(
+             baseDecl, decl, baseDecl->getInterfaceType());
 
     CanType parentPropertyCanTy =
       parentPropertyTy->getReducedType(

test/decl/class/override.swift

@@ -236,7 +236,10 @@ class IUOTestSubclassOkay : IUOTestBaseClass {
   override func oneC(_ x: AnyObject) {}
 }
 
-class GenericBase<T> {}
+class GenericBase<T> { // expected-note{{generic type 'GenericBase' declared here}}
+  var values: Int { 0 } // expected-note{{attempt to override property here}}
+}
+
 class ConcreteDerived: GenericBase<Int> {}
 
 class OverriddenWithConcreteDerived<T> {
@@ -424,3 +427,7 @@ class OverrideTypoSubclass: OverrideTypoBaseClass {
   override func foo(_ x: Itn) {} // expected-error {{cannot find type 'Itn' in scope}}
 }
 
+// https://github.com/swiftlang/swift/issues/74651
+class InvalidSubclass: GenericBase { // expected-error {{reference to generic type 'GenericBase' requires arguments in <...>}}
+  var values: Float { 0 } // expected-error {{property 'values' with type 'Float' cannot override a property with type 'Int'}}
+}