Replace uses of the word "accessor" in diagnostics with user-facing terminology (#74462)

In this PR i worked on replacing the word accessor in diagnostics with more user-facing terminologies like setter, getter, didSet Observer, and members based on the context of the message.

in some messages i didn't need to pass DescriptiveDeclKind instead i just changed the text copy itself.

i also updated tests, so you might find it easier to check my changes this way.

Please let me know if there's something i should've done in a better way, and request changes if needed. !

i can squash my commits after reviewing getting the PR Reviewed, just to make it easier to be checked commit by commit

Resolves #55887

Author: iMostfa

include/swift/AST/DiagnosticsSema.def

@@ -3963,8 +3963,8 @@ ERROR(attr_incompatible_with_objc,none,
       (DeclAttribute, DescriptiveDeclKind))
 
 ERROR(final_not_on_accessors,none,
-      "'final' cannot be applied to accessors, it must be put on the "
-      "%select{var|let|subscript}0", (unsigned))
+      "only the %select{property|subscript}0 itself can be marked as 'final'"
+      ,(bool))
 
 ERROR(override_rethrows_with_non_rethrows,none,
       "override of 'rethrows' %select{method|initializer}0 should also "
@@ -4996,8 +4996,8 @@ NOTE(candidate_is_not_assignable,none,
      (const ValueDecl *))
 
 NOTE(change_to_mutating,none,
-     "mark %select{method|accessor}0 'mutating' to make 'self' mutable",
-     (bool))
+     "mark %select{method|%1}0 'mutating' to make 'self' mutable",
+     (bool, StringRef))
 NOTE(masked_mutable_property,none,
      "add explicit '%0' to refer to mutable %1 of %2",
      (StringRef, DescriptiveDeclKind, Type))
@@ -6361,9 +6361,8 @@ NOTE(objc_witness_objc_requirement,none,
 ERROR(no_opaque_return_type_of,none,
       "unable to resolve type for _opaqueReturnTypeOf attribute", ())
 
-
 ERROR(objc_observing_accessor, none,
-      "observing accessors are not allowed to be marked @objc", ())
+      "observers (%0) are not allowed to be marked '@objc'", (DescriptiveDeclKind))
 ERROR(objc_init_accessor, none,
       "init accessors cannot be marked @objc", ())
 ERROR(objc_addressor, none,
@@ -7180,8 +7179,8 @@ ERROR(property_wrapper_computed, none,
       "property wrapper cannot be applied to a computed property",
       ())
 ERROR(property_wrapper_effectful,none,
-    "property wrappers currently cannot define an 'async' or 'throws' accessor",
-    ())
+      "property wrapper's 'wrappedValue' property cannot define an 'async' or 'throws' %0",
+    (DescriptiveDeclKind))
 
 ERROR(property_with_wrapper_conflict_attribute,none,
       "property %0 with a wrapper cannot also be "
@@ -7593,7 +7592,7 @@ ERROR(invalid_decl_in_macro_expansion,none,
       "macro expansion cannot introduce %0",
       (DescriptiveDeclKind))
 ERROR(let_accessor_expansion,none,
-      "cannot expand accessors on variable declared with 'let'",
+      "cannot expand accessor macro on variable declared with 'let'",
       ())
 ERROR(invalid_main_type_in_macro_expansion,none,
       "macro expansion cannot introduce '@main' type",

lib/AST/Decl.cpp

@@ -8394,8 +8394,9 @@ void VarDecl::emitLetToVarNoteIfSimple(DeclContext *UseDC) const {
       }
 
       auto &d = getASTContext().Diags;
+      auto descriptiveKindName = Decl::getDescriptiveKindName(FD->getDescriptiveKind());
       auto diags = d.diagnose(FD->getFuncLoc(), diag::change_to_mutating,
-                              isa<AccessorDecl>(FD));
+                              isa<AccessorDecl>(FD), descriptiveKindName);
       if (auto nonmutatingAttr =
               FD->getAttrs().getAttribute<NonMutatingAttr>()) {
         diags.fixItReplace(nonmutatingAttr->getLocation(), "mutating");

lib/Sema/TypeCheckAttr.cpp

@@ -1379,8 +1379,13 @@ void AttributeChecker::visitObjCAttr(ObjCAttr *attr) {
     if (!checkObjCDeclContext(D))
       error = diag::invalid_objc_decl_context;
     else if (auto accessor = dyn_cast<AccessorDecl>(func))
-      if (!accessor->isGetterOrSetter())
-        error = diag::objc_observing_accessor;
+      if (!accessor->isGetterOrSetter()) {
+        auto declKind = accessor->getDescriptiveKind();
+        diagnoseAndRemoveAttr(attr, diag::objc_observing_accessor, declKind)
+            .limitBehavior(behavior);
+        reason.describe(D);
+        return;
+      }
   } else if (isa<ConstructorDecl>(D) ||
              isa<DestructorDecl>(D) ||
              isa<SubscriptDecl>(D) ||
@@ -2584,10 +2589,8 @@ void AttributeChecker::visitFinalAttr(FinalAttr *attr) {
 
   if (auto *accessor = dyn_cast<AccessorDecl>(D)) {
     if (!attr->isImplicit()) {
-      unsigned Kind = 2;
-      if (auto *VD = dyn_cast<VarDecl>(accessor->getStorage()))
-        Kind = VD->isLet() ? 1 : 0;
-      diagnose(attr->getLocation(), diag::final_not_on_accessors, Kind)
+      diagnose(attr->getLocation(), diag::final_not_on_accessors,
+               isa<VarDecl>(accessor->getStorage()))
         .fixItRemove(attr->getRange());
       return;
     }

lib/Sema/TypeCheckDeclObjC.cpp

@@ -681,7 +681,8 @@ bool swift::isRepresentableInObjC(
       // willSet/didSet implementations are never exposed to objc, they are
       // always directly dispatched from the synthesized setter.
       diagnoseAndRemoveAttr(accessor, Reason.getAttr(),
-                            diag::objc_observing_accessor)
+                            diag::objc_observing_accessor,
+                            accessor->getDescriptiveKind())
           .limitBehavior(behavior);
       Reason.describe(accessor);
       return false;

lib/Sema/TypeCheckPropertyWrapper.cpp

@@ -108,7 +108,7 @@ static VarDecl *findValueProperty(ASTContext &ctx, NominalTypeDecl *nominal,
 
   // The property may not have any effects right now.
   if (auto getter = var->getEffectfulGetAccessor()) {
-    getter->diagnose(diag::property_wrapper_effectful);
+    getter->diagnose(diag::property_wrapper_effectful, getter->getDescriptiveKind());
     return nullptr;
   }
 

test/Macros/accessor_macros.swift

@@ -171,6 +171,6 @@ macro addGetterMacro() =
 #if TEST_DIAGNOSTICS
 struct S {
   @addGetterMacro let x: Int
-  // expected-warning@-1 {{cannot expand accessors on variable declared with 'let'; this is an error in the Swift 6 language mode}}
+  // expected-warning@-1 {{cannot expand accessor macro on variable declared with 'let'; this is an error in the Swift 6 language mode}}
 }
 #endif

test/Sema/immutability.swift

@@ -149,7 +149,7 @@ struct SomeStruct {
 
   var p: Int {
     // Getters default to non-mutating.
-    get {          // expected-note {{mark accessor 'mutating' to make 'self' mutable}} {{5-5=mutating }}
+    get {          // expected-note {{mark getter 'mutating' to make 'self' mutable}} {{5-5=mutating }}
       iv = 37 // expected-error {{cannot assign to property: 'self' is immutable}}
       return 42
     }
@@ -168,13 +168,13 @@ struct SomeStruct {
       return 42
     }
     nonmutating
-    set {      // expected-note {{mark accessor 'mutating' to make 'self' mutable}} {{-1:5-16=mutating}}
+    set {      // expected-note {{mark setter 'mutating' to make 'self' mutable}} {{-1:5-16=mutating}}
       iv = newValue // expected-error {{cannot assign to property: 'self' is immutable}}
     }
   }
 
   var r : Int {
-    get {        // expected-note {{mark accessor 'mutating' to make 'self' mutable}} {{5-5=mutating }}
+    get {        // expected-note {{mark getter 'mutating' to make 'self' mutable}} {{5-5=mutating }}
       iv = 37 // expected-error {{cannot assign to property: 'self' is immutable}}
       return 42
     }
@@ -708,7 +708,7 @@ extension JustAProtocol {
   var foo: String {
     get { return name }
     nonmutating set { name = newValue } // expected-error {{cannot assign to property: 'self' is immutable}} 
-    // expected-note@-1 {{mark accessor 'mutating' to make 'self' mutable}}{{5-16=mutating}}
+    // expected-note@-1 {{mark setter 'mutating' to make 'self' mutable}}{{5-16=mutating}}
   }
 
   nonmutating func bar() { // expected-note {{mark method 'mutating' to make 'self' mutable}}{{3-14=mutating}}

test/attr/attr_objc.swift

@@ -142,10 +142,10 @@ class subject_getterSetter1 {
   }
 
   var observingAccessorsVar1: Int = 0 {
-    @objc // expected-error {{observing accessors are not allowed to be marked @objc}} {{5-11=}}
+    @objc // expected-error {{observers (willSet observer) are not allowed to be marked '@objc'}} {{5-11=}}
     willSet {
     }
-    @objc // expected-error {{observing accessors are not allowed to be marked @objc}} {{5-11=}}
+    @objc // expected-error {{observers (didSet observer) are not allowed to be marked '@objc'}} {{5-11=}}
     didSet {
     }
   }
@@ -2091,7 +2091,7 @@ class BadClass2 {
   }
 
   var prop3: Int {
-    @objc(setProperty:) // expected-error{{observing accessors are not allowed to be marked @objc}} {{5-25=}}
+    @objc(setProperty:) // expected-error{{observers (didSet observer) are not allowed to be marked '@objc'}} {{5-25=}}
     didSet { }
   }
 }

test/decl/ext/extensions.swift

@@ -200,13 +200,13 @@ extension DoesNotImposeClassReq_2 where Self : AnyObject {
   var wrappingProperty1: String {
     get { property }
     set { property = newValue } // expected-error {{cannot assign to property: 'self' is immutable}}
-    // expected-note@-1 {{mark accessor 'mutating' to make 'self' mutable}}{{5-5=mutating }}
+    // expected-note@-1 {{mark setter 'mutating' to make 'self' mutable}}{{5-5=mutating }}
   }
 
   var wrappingProperty2: String {
     get { property }
     nonmutating set { property = newValue } // expected-error {{cannot assign to property: 'self' is immutable}}
-    // expected-note@-1 {{mark accessor 'mutating' to make 'self' mutable}}{{5-16=mutating}}
+    // expected-note@-1 {{mark setter 'mutating' to make 'self' mutable}}{{5-16=mutating}}
   }
 
   var wrappingProperty3: String {

test/decl/subscript/subscripting.swift

@@ -320,7 +320,7 @@ struct MutableComputedGetter {
 struct MutableSubscriptInGetter {
   var value: Int
   subscript(index: Int) -> Int {
-    get { // expected-note {{mark accessor 'mutating' to make 'self' mutable}}
+    get { // expected-note {{mark getter 'mutating' to make 'self' mutable}}
       value = 5 // expected-error{{cannot assign to property: 'self' is immutable}}
       return 5
     }

test/decl/var/effectful_property_wrapper.swift

@@ -10,7 +10,7 @@ struct Abstraction<T> {
     init(_ initial : T) { self.value = initial }
 
     var wrappedValue : T {
-        get throws { return value } // expected-error{{property wrappers currently cannot define an 'async' or 'throws' accessor}}
+        get throws { return value } // expected-error{{property wrapper's 'wrappedValue' property cannot define an 'async' or 'throws' getter}}
     }
 
     // its OK to have effectful props that are not `wrappedValue`