Soften ObjC selector conflicts from access notes

Author: beccadax

include/swift/AST/DiagnosticsSema.def

@@ -5018,10 +5018,11 @@ NOTE(objc_declared_here,none,
      OBJC_DIAG_SELECT " declared here",
      (unsigned, DeclName))
 
+// %2 and %3 are unused to make signature match with diag::objc_redecl.
 ERROR(objc_redecl_same,none,
-      OBJC_DIAG_SELECT " with Objective-C selector %2 conflicts with "
+      OBJC_DIAG_SELECT " with Objective-C selector %4 conflicts with "
       "previous declaration with the same Objective-C selector",
-      (unsigned, DeclName, ObjCSelector))
+      (unsigned, DeclName, unsigned, DeclName, ObjCSelector))
 
 ERROR(objc_override_other,none,
       OBJC_DIAG_SELECT " with Objective-C selector %4 conflicts with "

include/swift/AST/SourceFile.h

@@ -241,6 +241,8 @@ class SourceFile final : public FileUnit {
   /// unsatisfied, which might conflict with other Objective-C methods.
   std::vector<ObjCUnsatisfiedOptReq> ObjCUnsatisfiedOptReqs;
 
+  /// A selector that is used by two different declarations in the same class.
+  /// Fields: classDecl, selector, isInstanceMethod.
   using ObjCMethodConflict = std::tuple<ClassDecl *, ObjCSelector, bool>;
 
   /// List of Objective-C member conflicts we have found during type checking.

lib/Sema/TypeCheckDeclObjC.cpp

@@ -2411,6 +2411,17 @@ getObjCMethodConflictDecls(const SourceFile::ObjCMethodConflict &conflict) {
   return classDecl->lookupDirect(selector, isInstanceMethod);
 }
 
+static ObjCAttr *getObjCAttrIfFromAccessNote(ValueDecl *VD) {
+  if (auto objc = VD->getAttrs().getAttribute<ObjCAttr>())
+    if (objc->getAddedByAccessNote())
+      return objc;
+
+  if (auto accessor = dyn_cast<AccessorDecl>(VD))
+    return getObjCAttrIfFromAccessNote(accessor->getStorage());
+
+  return nullptr;
+}
+
 bool swift::diagnoseObjCMethodConflicts(SourceFile &sf) {
   // If there were no conflicts, we're done.
   if (sf.ObjCMethodConflicts.empty())
@@ -2473,6 +2484,10 @@ bool swift::diagnoseObjCMethodConflicts(SourceFile &sf) {
           return false; \
       } while (0)
 
+      // Is one of these from an access note?
+      RULE(getObjCAttrIfFromAccessNote(a),
+           getObjCAttrIfFromAccessNote(b));
+
       // Is one of these from the main declaration?
       RULE(!isa<ExtensionDecl>(a->getDeclContext()),
            !isa<ExtensionDecl>(b->getDeclContext()));
@@ -2505,18 +2520,25 @@ bool swift::diagnoseObjCMethodConflicts(SourceFile &sf) {
         if (auto accessor = dyn_cast<AccessorDecl>(originalMethod))
           originalDecl = accessor->getStorage();
 
-      if (diagInfo == origDiagInfo) {
-        Ctx.Diags.diagnose(conflictingDecl, diag::objc_redecl_same,
-                           diagInfo.first, diagInfo.second, selector);
+      bool redeclSame = (diagInfo == origDiagInfo);
+      auto diag = Ctx.Diags.diagnose(conflictingDecl,
+                                     redeclSame ? diag::objc_redecl_same
+                                                : diag::objc_redecl,
+                                     diagInfo.first, diagInfo.second,
+                                     origDiagInfo.first, origDiagInfo.second,
+                                     selector);
+
+      auto objcAttr = getObjCAttrIfFromAccessNote(conflictingDecl);
+      swift::softenIfAccessNote(conflictingDecl, objcAttr, diag);
+      if (objcAttr)
+        objcAttr->setInvalid();
+
+      if (redeclSame)
         Ctx.Diags.diagnose(originalDecl, diag::invalid_redecl_prev,
                            originalDecl->getBaseName());
-      } else {
-        Ctx.Diags.diagnose(conflictingDecl, diag::objc_redecl, diagInfo.first,
-                           diagInfo.second, origDiagInfo.first,
-                           origDiagInfo.second, selector);
+      else
         Ctx.Diags.diagnose(originalDecl, diag::objc_declared_here,
                            origDiagInfo.first, origDiagInfo.second);
-      }
     }
   }
 

test/attr/attr_objc.swift

@@ -2366,33 +2366,33 @@ class SubclassImplicitClassThrows1 : ImplicitClassThrows1 {
 class ThrowsRedecl1 {
   @objc // access-note-move{{ThrowsRedecl1.method1(_:error:)}}
   func method1(_ x: Int, error: Class_ObjC1) { } // expected-note{{declared here}}
-  @objc // access-note-move{{ThrowsRedecl1.method1(_:)}}
-  func method1(_ x: Int) throws { } // expected-error {{with Objective-C selector 'method1:error:'}}
+  @objc // bad-access-note-move{{ThrowsRedecl1.method1(_:)}}
+  func method1(_ x: Int) throws { } // access-note-adjust{{@objc}} expected-error {{method 'method1' with Objective-C selector 'method1:error:' conflicts with method 'method1(_:error:)' with the same Objective-C selector}}
 
   @objc // access-note-move{{ThrowsRedecl1.method2AndReturnError(_:)}}
   func method2AndReturnError(_ x: Int) { } // expected-note{{declared here}}
-  @objc // access-note-move{{ThrowsRedecl1.method2()}}
-  func method2() throws { } // expected-error {{with Objective-C selector 'method2AndReturnError:'}}
+  @objc // bad-access-note-move{{ThrowsRedecl1.method2()}}
+  func method2() throws { } // access-note-adjust{{@objc}} expected-error {{method 'method2()' with Objective-C selector 'method2AndReturnError:' conflicts with method 'method2AndReturnError' with the same Objective-C selector}}
 
   @objc // access-note-move{{ThrowsRedecl1.method3(_:error:closure:)}}
   func method3(_ x: Int, error: Int, closure: @escaping (Int) -> Int) { }  // expected-note{{declared here}}
-  @objc // access-note-move{{ThrowsRedecl1.method3(_:closure:)}}
-  func method3(_ x: Int, closure: (Int) -> Int) throws { } // expected-error {{with Objective-C selector 'method3:error:closure:'}}
+  @objc // bad-access-note-move{{ThrowsRedecl1.method3(_:closure:)}}
+  func method3(_ x: Int, closure: (Int) -> Int) throws { } // access-note-adjust{{@objc}} expected-error {{method 'method3(_:closure:)' with Objective-C selector 'method3:error:closure:' conflicts with method 'method3(_:error:closure:)' with the same Objective-C selector}}
 
   @objc(initAndReturnError:) // access-note-move{{ThrowsRedecl1.initMethod1(error:)}}
   func initMethod1(error: Int) { } // expected-note{{declared here}}
-  @objc // access-note-move{{ThrowsRedecl1.init()}}
-  init() throws { } // expected-error {{with Objective-C selector 'initAndReturnError:'}}
+  @objc // bad-access-note-move{{ThrowsRedecl1.init()}}
+  init() throws { } // access-note-adjust{{@objc}} expected-error {{initializer 'init()' with Objective-C selector 'initAndReturnError:' conflicts with method 'initMethod1(error:)' with the same Objective-C selector}}
 
   @objc(initWithString:error:) // access-note-move{{ThrowsRedecl1.initMethod2(string:error:)}}
   func initMethod2(string: String, error: Int) { } // expected-note{{declared here}}
-  @objc // access-note-move{{ThrowsRedecl1.init(string:)}}
-  init(string: String) throws { } // expected-error {{with Objective-C selector 'initWithString:error:'}}
+  @objc // bad-access-note-move{{ThrowsRedecl1.init(string:)}}
+  init(string: String) throws { } // access-note-adjust{{@objc}} expected-error {{initializer 'init(string:)' with Objective-C selector 'initWithString:error:' conflicts with method 'initMethod2(string:error:)' with the same Objective-C selector}}
 
   @objc(initAndReturnError:fn:) // access-note-move{{ThrowsRedecl1.initMethod3(error:fn:)}}
   func initMethod3(error: Int, fn: @escaping (Int) -> Int) { } // expected-note{{declared here}}
-  @objc // access-note-move{{ThrowsRedecl1.init(fn:)}}
-  init(fn: (Int) -> Int) throws { } // expected-error {{with Objective-C selector 'initAndReturnError:fn:'}}
+  @objc // bad-access-note-move{{ThrowsRedecl1.init(fn:)}}
+  init(fn: (Int) -> Int) throws { } // access-note-adjust{{@objc}} expected-error {{initializer 'init(fn:)' with Objective-C selector 'initAndReturnError:fn:' conflicts with method 'initMethod3(error:fn:)' with the same Objective-C selector}}
 }
 
 class ThrowsObjCName {