[Diag] QoI: ownership in protocol check should not be 'else' clause

lib/Sema/TypeCheckAttr.cpp

@@ -2183,21 +2183,17 @@ void TypeChecker::checkReferenceOwnershipAttr(VarDecl *var,
 
     diagnose(var->getStartLoc(), D, ownershipKind, underlyingType);
     attr->setInvalid();
-  } else if (isa<ProtocolDecl>(var->getDeclContext()) &&
-             !cast<ProtocolDecl>(var->getDeclContext())->isObjC()) {
+  }
+
+  auto PDC = dyn_cast<ProtocolDecl>((var->getDeclContext()));
+  if (PDC && !PDC->isObjC()) {
     // Ownership does not make sense in protocols, except for "weak" on
     // properties of Objective-C protocols.
-    if (Context.isSwiftVersionAtLeast(5))
-      diagnose(attr->getLocation(),
-               diag::ownership_invalid_in_protocols,
-               ownershipKind)
-        .fixItRemove(attr->getRange());
-    else
-      diagnose(attr->getLocation(),
-               diag::ownership_invalid_in_protocols_compat_warning,
-               ownershipKind)
-        .fixItRemove(attr->getRange());
-
+    auto D = Context.isSwiftVersionAtLeast(5)
+           ? diag::ownership_invalid_in_protocols
+           : diag::ownership_invalid_in_protocols_compat_warning;
+    diagnose(attr->getLocation(), D, ownershipKind)
+      .fixItRemove(attr->getRange());
     attr->setInvalid();
   }
 

test/Compatibility/ownership_protocol.swift

@@ -4,9 +4,15 @@
 class SomeClass {}
 
 protocol P {
-  weak var foo: SomeClass? { get set } // expected-warning {{'weak' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
-  unowned var foo2: SomeClass { get set } // expected-warning {{'unowned' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
-  weak var foo3: Int? { get set } // expected-error {{'weak' may only be applied to class and class-bound protocol types, not 'Int'}}
-  unowned var foo4: Int { get set } // expected-error {{'unowned' may only be applied to class and class-bound protocol types, not 'Int'}}
+  // expected-warning@+1 {{'weak' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
+  weak var foo: SomeClass? { get set }
+  // expected-warning@+1 {{'unowned' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
+  unowned var foo2: SomeClass { get set }
+  // expected-warning@+2 {{'weak' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
+  // expected-error@+1 {{'weak' may only be applied to class and class-bound protocol types, not 'Int'}}
+  weak var foo3: Int? { get set }
+  // expected-warning@+2 {{'unowned' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
+  // expected-error@+1 {{'unowned' may only be applied to class and class-bound protocol types, not 'Int'}}
+  unowned var foo4: Int { get set }
 }
 

test/decl/protocol/ownership_protocol.swift

@@ -3,10 +3,16 @@
 class SomeClass {}
 
 protocol P {
-  weak var foo: SomeClass? { get set } // expected-error {{'weak' cannot be applied to a property declaration in a protocol}}
-  unowned var foo2: SomeClass { get set } // expected-error {{'unowned' cannot be applied to a property declaration in a protocol}}
-  weak var foo3: Int? { get set } // expected-error {{'weak' may only be applied to class and class-bound protocol types, not 'Int'}}
-  unowned var foo4: Int { get set } // expected-error {{'unowned' may only be applied to class and class-bound protocol types, not 'Int'}}
+  // expected-error@+1 {{'weak' cannot be applied to a property declaration in a protocol}}
+  weak var foo: SomeClass? { get set }
+  // expected-error@+1 {{'unowned' cannot be applied to a property declaration in a protocol}}
+  unowned var foo2: SomeClass { get set }
+  // expected-error@+2 {{'weak' cannot be applied to a property declaration in a protocol}}
+  // expected-error@+1 {{'weak' may only be applied to class and class-bound protocol types, not 'Int'}}
+  weak var foo3: Int? { get set }
+  // expected-error@+2 {{'unowned' cannot be applied to a property declaration in a protocol}}
+  // expected-error@+1 {{'unowned' may only be applied to class and class-bound protocol types, not 'Int'}}
+  unowned var foo4: Int { get set }
   var foo9: SomeClass? { get }
 }
 

test/decl/protocol/protocols.swift

@@ -465,6 +465,7 @@ protocol ShouldntCrash {
 
 // rdar://problem/18168866
 protocol FirstProtocol {
+    // expected-warning@+1 {{'weak' should not be applied to a property declaration in a protocol and will be disallowed in future versions}}
     weak var delegate : SecondProtocol? { get } // expected-error{{'weak' must not be applied to non-class-bound 'SecondProtocol'; consider adding a protocol conformance that has a class bound}}
 }