Add a Fixit to Rewrite NSObject.hash(into:) Overrides

Author: CodaFi

lib/Sema/TypeCheckDeclOverride.cpp

@@ -1012,10 +1012,12 @@ static void checkOverrideAccessControl(ValueDecl *baseDecl, ValueDecl *decl,
     // NSObject.hashValue and NSObject.hash(into:) are not overridable;
     // one should override NSObject.hash instead.
     if (isNSObjectHashValue(baseDecl)) {
-      diags.diagnose(decl, diag::override_nsobject_hashvalue_error)
+      decl->diagnose(diag::override_nsobject_hashvalue_error)
         .fixItReplace(SourceRange(decl->getNameLoc()), "hash");
     } else if (isNSObjectHashMethod(baseDecl)) {
-      diags.diagnose(decl, diag::override_nsobject_hash_error);
+      decl->diagnose(diag::override_nsobject_hash_error)
+        .fixItReplace(cast<FuncDecl>(decl)->getFuncLoc(), getTokenText(tok::kw_var))
+        .fixItReplace(cast<FuncDecl>(decl)->getParameters()->getSourceRange(), ": Int");
     } else {
       diags.diagnose(decl, diag::override_of_non_open,
                      decl->getDescriptiveKind());

stdlib/public/Darwin/ObjectiveC/ObjectiveC.swift

@@ -231,7 +231,7 @@ extension NSObject : Equatable, Hashable {
   ///
   /// NSObject implements this by feeding `self.hash` to the hasher.
   ///
-  /// 'NSObject.hash(into:)' is not overridable; subclasses can customize
+  /// `NSObject.hash(into:)` is not overridable; subclasses can customize
   /// hashing by overriding the `hash` property.
   public func hash(into hasher: inout Hasher) {
     hasher.combine(self.hash)

test/ClangImporter/objc_override.swift

@@ -116,7 +116,7 @@ class MyHashableNSObject: NSObject {
   }
 
   override func hash(into hasher: inout Hasher) {
-    // expected-error@-1 {{'NSObject.hash(into:)' is not overridable; did you mean to override 'NSObject.hash'?}}
+    // expected-error@-1 {{'NSObject.hash(into:)' is not overridable; did you mean to override 'NSObject.hash'?}} {{12-16=var}} {{21-48=: Int}}
   }
 }
 

test/stdlib/NSObject-hashing.swift

@@ -12,6 +12,6 @@ class Foo: NSObject {
   }
 
   override func hash(into hasher: inout Hasher) {
-    // expected-error@-1 {{'NSObject.hash(into:)' is not overridable; did you mean to override 'NSObject.hash'?}}
+    // expected-error@-1 {{'NSObject.hash(into:)' is not overridable; did you mean to override 'NSObject.hash'?}} {{12-16=var}} {{21-48=: Int}}
   }
 }