SE-0022: Address Jordan's review comments about #selector.

Author: DougGregor

include/swift/AST/DeclContext.h

@@ -405,8 +405,9 @@ class alignas(1 << DeclContextAlignInBits) DeclContext {
                        LazyResolver *typeResolver,
                        SmallVectorImpl<ValueDecl *> &decls) const;
 
-  /// Look up Objective-C methods with the given selector.
-  void lookupObjCMethods(
+  /// Look up all Objective-C methods with the given selector visible
+  /// in the enclosing module.
+  void lookupAllObjCMethods(
          ObjCSelector selector,
          SmallVectorImpl<AbstractFunctionDecl *> &results) const;
 

include/swift/AST/Module.h

@@ -919,7 +919,8 @@ class SourceFile final : public FileUnit {
 
   /// A mapping from Objective-C selectors to the methods that have
   /// those selectors.
-  llvm::DenseMap<ObjCSelector, std::vector<AbstractFunctionDecl *>> ObjCMethods;
+  llvm::DenseMap<ObjCSelector, llvm::TinyPtrVector<AbstractFunctionDecl *>>
+    ObjCMethods;
 
   template <typename T>
   using OperatorMap = llvm::DenseMap<Identifier,llvm::PointerIntPair<T,1,bool>>;

lib/AST/NameLookup.cpp

@@ -1375,7 +1375,7 @@ bool DeclContext::lookupQualified(Type type,
   return !decls.empty();
 }
 
-void DeclContext::lookupObjCMethods(
+void DeclContext::lookupAllObjCMethods(
        ObjCSelector selector,
        SmallVectorImpl<AbstractFunctionDecl *> &results) const {
   // Collect all of the methods with this selector.

lib/Sema/CSApply.cpp

@@ -3323,12 +3323,8 @@ namespace {
 
         // Look through an implicit force-value.
         if (auto force = dyn_cast<ForceValueExpr>(subExpr)) {
-          if (force->isImplicit()) {
-            subExpr = force->getSubExpr();
-            continue;
-          }
-
-          break;
+          subExpr = force->getSubExpr();
+          continue;
         }
 
         // Look through implicit open-existential operations.

lib/Sema/CSGen.cpp

@@ -2482,7 +2482,7 @@ namespace {
 
     Type visitObjCSelectorExpr(ObjCSelectorExpr *E) {
       // #selector only makes sense when we have the Objective-C
-      // #runtime.
+      // runtime.
       auto &tc = CS.getTypeChecker();
       if (!tc.Context.LangOpts.EnableObjCInterop) {
         tc.diagnose(E->getLoc(), diag::expr_selector_no_objc_runtime);

lib/Sema/MiscDiagnostics.cpp

@@ -2025,7 +2025,7 @@ class ObjCSelectorWalker : public ASTWalker {
 
     // Look for methods with this selector.
     SmallVector<AbstractFunctionDecl *, 8> allMethods;
-    DC->lookupObjCMethods(*selector, allMethods);
+    DC->lookupAllObjCMethods(*selector, allMethods);
 
     // If we didn't find any methods, complain.
     if (allMethods.empty()) {

test/IRGen/objc_selector.sil

@@ -1,14 +1,13 @@
 // RUN: %target-swift-frontend -emit-ir %s | FileCheck %s
 
 // REQUIRES: objc_interop
-// REQUIRES: CPU=x86_64
 
 sil_stage canonical
 
 import Builtin
 
 // CHECK: @"\01L_selector_data(help:me:)" = private global [9 x i8] c"help:me:\00", section "__TEXT,__objc_methname,cstring_literals"
-// CHECK: @"\01L_selector(help:me:)" = private externally_initialized global i8* getelementptr inbounds ([9 x i8], [9 x i8]* @"\01L_selector_data(help:me:)", i64 0, i64 0), section "__DATA,__objc_selrefs,literal_pointers,no_dead_strip"
+// CHECK: @"\01L_selector(help:me:)" = private externally_initialized global i8* getelementptr inbounds ([9 x i8], [9 x i8]* @"\01L_selector_data(help:me:)", {{i(32|64)}} 0, {{i(32|64)}} 0), section "__DATA,__objc_selrefs,literal_pointers,no_dead_strip"
 
 // CHECK-LABEL: define i8* @objc_selector_literal() #0 {
 sil @objc_selector_literal : $@convention(thin) () -> Builtin.RawPointer {

test/expr/unary/selector/fixits.filecheck

@@ -1,3 +1,5 @@
+// REQUIRES: objc_interop
+
 // RUN: rm -rf %t
 // RUN: mkdir -p %t
 // RUN: rm -rf %t.overlays
@@ -21,9 +23,14 @@
 // RUN: %S/../../../../utils/apply-fixit-edits.py %t.remapping
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk-nosource -I %t.overlays) -parse %t.sources/fixits.swift 2> %t.result
 
-// RUN: FileCheck %S/fixits.filecheck < %t.result
+// RUN: FileCheck %s < %t.result
 // RUN: grep -c "warning:" %t.result | grep 4
 
+// CHECK: warning: no method declared with Objective-C selector 'unknownMethodWithValue:label:'
+// CHECK: warning: string literal is not a valid Objective-C selector
+// CHECK: warning: no method declared with Objective-C selector 'unknownMethodWithValue:label:'
+// CHECK: warning: string literal is not a valid Objective-C selector
+
 import Foundation
 
 class Bar : Foo {

test/expr/unary/selector/fixits.swift

@@ -7,13 +7,17 @@ import ObjectiveC
 @objc class B { }
 
 class C1 {
+  @objc init(a: A, b: B) { }
+
   @objc func method1(a: A, b: B) { }
   @objc(someMethodWithA:B:) func method2(a: A, b: B) { }
 
   @objc class func method3(a: A, b: B) { } // expected-note{{found this candidate}}
   @objc class func method3(a a: A, b: B) { } // expected-note{{found this candidate}}
 
   @objc var a: A = A() // expected-note{{'a' declared here}}
+
+  @objc func getC1() -> AnyObject { return self }
 }
 
 @objc protocol P1 {
@@ -25,7 +29,7 @@ extension C1 {
   final func method6() { } // expected-note{{add '@objc' to expose this method to Objective-C}}{{3-3=@objc }}
 }
 
-func testSelector(c1: C1, p1: P1) {
+func testSelector(c1: C1, p1: P1, obj: AnyObject) {
   // Instance methods on an instance
   let sel1 = #selector(c1.method1)
   _ = #selector(c1.method1(_:b:))
@@ -50,6 +54,14 @@ func testSelector(c1: C1, p1: P1) {
   _ = #selector(p1.dynamicType.method5)
   _ = #selector(p1.dynamicType.method5(_:b:))
 
+  // Interesting expressions that refer to methods.
+  _ = #selector(Swift.AnyObject.method1)
+  _ = #selector(AnyObject.method1!)
+  _ = #selector(obj.getC1?().method1)
+
+  // Initializers
+  _ = #selector(C1.init(a:b:))
+
   // Make sure the result has type "ObjectiveC.Selector"
   let sel2: Selector
   sel2 = sel1
@@ -62,7 +74,7 @@ func testAmbiguity() {
 
 func testProperties(c1: C1) {
   _ = #selector(c1.a) // expected-error{{argument of '#selector' cannot refer to a property}}
-  _ = #selector(C1.a) // expected-error{{instance member 'a' cannot be used on type 'C1'}}
+  _ = #selector(C1.a) // FIXME poor diagnostic: expected-error{{instance member 'a' cannot be used on type 'C1'}}
 }
 
 func testNonObjC(c1: C1) {
@@ -81,3 +93,10 @@ func testParseErrors3(c1: C1) {
   #selector( // expected-note{{to match this opening '('}}
       c1.method1(_:b:) // expected-error{{expected ')' to complete '#selector' expression}}
 }
+
+func testParseErrors4() {
+  // Subscripts
+  _ = #selector(C1.subscript) // expected-error{{expected member name following '.'}}
+  // expected-error@-1{{consecutive statements on a line must be separated by ';'}}
+  // expected-error@-2{{expected '(' for subscript parameters}}
+}