[AST/Sema] SE-0487: Remove @preEnumExtensibility attribute

(cherry picked from commit 0444d29)

Author: xedin

include/swift/AST/DeclAttr.def

@@ -887,13 +887,9 @@ SIMPLE_DECL_ATTR(concurrent, Concurrent,
   ABIBreakingToAdd | ABIBreakingToRemove | APIBreakingToAdd | APIBreakingToRemove | UnconstrainedInABIAttr,
   170)
 
-SIMPLE_DECL_ATTR(preEnumExtensibility, PreEnumExtensibility,
-  OnEnum,
-  ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIBreakingToRemove | UnconstrainedInABIAttr,
-  171)
-DECL_ATTR_FEATURE_REQUIREMENT(PreEnumExtensibility, NonexhaustiveAttribute)
+// Unused '171': Used to be `@preEnumExtensibility`
 
-LAST_DECL_ATTR(PreEnumExtensibility)
+LAST_DECL_ATTR(Concurrent)
 
 #undef DECL_ATTR_ALIAS
 #undef CONTEXTUAL_DECL_ATTR_ALIAS

include/swift/AST/DiagnosticsSema.def

@@ -8724,9 +8724,6 @@ ERROR(nonexhaustive_attr_on_internal_type,none,
       "%select{private|fileprivate|internal|%error|%error|%error}1",
       (DeclName, AccessLevel))
 
-ERROR(pre_enum_extensibility_without_nonexhaustive,none,
-      "%0 can only be used together with '@nonexhaustive' attribute", (DeclAttribute))
-
 //===----------------------------------------------------------------------===//
 // MARK: `using` declaration
 //===----------------------------------------------------------------------===//

lib/AST/ASTDumper.cpp

@@ -5066,7 +5066,6 @@ class PrintAttribute : public AttributeVisitor<PrintAttribute, void, Label>,
   TRIVIAL_ATTR_PRINTER(WeakLinked, weak_linked)
   TRIVIAL_ATTR_PRINTER(Nonexhaustive, nonexhaustive)
   TRIVIAL_ATTR_PRINTER(Concurrent, concurrent)
-  TRIVIAL_ATTR_PRINTER(PreEnumExtensibility, preEnumExtensibility)
 
 #undef TRIVIAL_ATTR_PRINTER
 

lib/AST/ASTPrinter.cpp

@@ -3328,8 +3328,7 @@ suppressingFeatureAddressableTypes(PrintOptions &options,
 static void
 suppressingFeatureNonexhaustiveAttribute(PrintOptions &options,
                                          llvm::function_ref<void()> action) {
-  ExcludeAttrRAII scope1(options.ExcludeAttrList, DeclAttrKind::Nonexhaustive);
-  ExcludeAttrRAII scope2(options.ExcludeAttrList, DeclAttrKind::PreEnumExtensibility);
+  ExcludeAttrRAII scope(options.ExcludeAttrList, DeclAttrKind::Nonexhaustive);
   action();
 }
 

lib/ASTGen/Sources/ASTGen/DeclAttrs.swift

@@ -229,7 +229,6 @@ extension ASTGenVisitor {
         .eagerMove,
         .exported,
         .nonexhaustive,
-        .preEnumExtensibility,
         .discardableResult,
         .disfavoredOverload,
         .dynamicMemberLookup,

lib/Sema/TypeCheckAttr.cpp

@@ -258,14 +258,6 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     }
   }
 
-  void visitPreEnumExtensibilityAttr(PreEnumExtensibilityAttr *attr) {
-    if (!D->getAttrs().hasAttribute<NonexhaustiveAttr>()) {
-      diagnoseAndRemoveAttr(
-          attr, diag::pre_enum_extensibility_without_nonexhaustive, attr);
-      return;
-    }
-  }
-
   void visitAlignmentAttr(AlignmentAttr *attr) {
     // Alignment must be a power of two.
     auto value = attr->getValue();

lib/Sema/TypeCheckDeclOverride.cpp

@@ -1617,7 +1617,6 @@ namespace  {
     UNINTERESTING_ATTR(Optimize)
     UNINTERESTING_ATTR(Exclusivity)
     UNINTERESTING_ATTR(Nonexhaustive)
-    UNINTERESTING_ATTR(PreEnumExtensibility)
     UNINTERESTING_ATTR(NoLocks)
     UNINTERESTING_ATTR(NoAllocation)
     UNINTERESTING_ATTR(NoRuntime)