AST: Adjust declaration printing when NoncopyableGenerics2 is suppressed.

When printing declarations with `NoncopyableGenerics2` suppressed we must avoid
printing the `@_preInverseGenerics` attribute and any `borrowing` or
`consuming` parameter ownership modifiers.

Author: tshortli

include/swift/AST/PrintOptions.h

@@ -385,6 +385,9 @@ struct PrintOptions {
   /// Suppress Noncopyable generics.
   bool SuppressNoncopyableGenerics = false;
 
+  /// Suppress printing of `borrowing` and `consuming`.
+  bool SuppressNoncopyableOwnershipModifiers = false;
+
   /// List of attribute kinds that should not be printed.
   std::vector<AnyAttrKind> ExcludeAttrList = {
       DeclAttrKind::Transparent, DeclAttrKind::Effects,

lib/AST/ASTPrinter.cpp

@@ -1138,7 +1138,16 @@ class PrintAST : public ASTVisitor<PrintAST> {
     Printer.callPrintDeclPre(D, Options.BracketOptions);
 
     if (Options.PrintCompatibilityFeatureChecks) {
-      printWithCompatibilityFeatureChecks(Printer, Options, D, [&]{
+      printWithCompatibilityFeatureChecks(Printer, Options, D, [&] {
+        // If we are in a scope where non-copyable generics are being suppressed
+        // and we are also printing a decl that has @_preInverseGenerics, make
+        // sure we also suppress printing ownership modifiers that were added
+        // to satisfy the requirements of non-copyability.
+        llvm::SaveAndRestore<bool> scope(
+            Options.SuppressNoncopyableOwnershipModifiers,
+            Options.SuppressNoncopyableGenerics &&
+                D->getAttrs().hasAttribute<PreInverseGenericsAttr>());
+
         ASTVisitor::visit(D);
       });
     } else {
@@ -3123,9 +3132,12 @@ static void suppressingFeatureAssociatedTypeImplements(PrintOptions &options,
 static void suppressingFeatureNoncopyableGenerics(
     PrintOptions &options,
     llvm::function_ref<void()> action) {
+  unsigned originalExcludeAttrCount = options.ExcludeAttrList.size();
+  options.ExcludeAttrList.push_back(DeclAttrKind::PreInverseGenerics);
   llvm::SaveAndRestore<bool> scope(
       options.SuppressNoncopyableGenerics, true);
   action();
+  options.ExcludeAttrList.resize(originalExcludeAttrCount);
 }
 
 /// Suppress the printing of a particular feature.
@@ -3680,10 +3692,14 @@ static void printParameterFlags(ASTPrinter &printer,
     printer.printKeyword("inout", options, " ");
     break;
   case ParamSpecifier::Borrowing:
-    printer.printKeyword("borrowing", options, " ");
+    if (!options.SuppressNoncopyableOwnershipModifiers) {
+      printer.printKeyword("borrowing", options, " ");
+    }
     break;
   case ParamSpecifier::Consuming:
-    printer.printKeyword("consuming", options, " ");
+    if (!options.SuppressNoncopyableOwnershipModifiers) {
+      printer.printKeyword("consuming", options, " ");
+    }
     break;
   case ParamSpecifier::LegacyShared:
     printer.printKeyword("__shared", options, " ");

lib/AST/FeatureSet.cpp

@@ -506,6 +506,9 @@ static bool usesFeatureRawLayout(Decl *decl) {
 UNINTERESTING_FEATURE(Embedded)
 
 static bool usesFeatureNoncopyableGenerics(Decl *decl) {
+  if (decl->getAttrs().hasAttribute<PreInverseGenericsAttr>())
+    return true;
+
   if (auto *valueDecl = dyn_cast<ValueDecl>(decl)) {
     if (isa<StructDecl, EnumDecl, ClassDecl>(decl)) {
       auto *nominalDecl = cast<NominalTypeDecl>(valueDecl);

test/ModuleInterface/Inputs/NoncopyableGenerics_Misc.swift

@@ -106,3 +106,6 @@ extension Outer.InnerStruct {
 
 @_preInverseGenerics
 public func old_swap<T: ~Copyable>(_ a: inout T, _ b: inout T) {}
+
+@_preInverseGenerics
+public func borrowsNoncopyable<T: ~Copyable>(_ t: borrowing T) {}

test/ModuleInterface/noncopyable_generics.swift

@@ -144,8 +144,18 @@ import NoncopyableGenerics_Misc
 
 // CHECK-MISC: #if compiler(>=5.3) && $NoncopyableGenerics
 // CHECK-MISC-NEXT: @_preInverseGenerics public func old_swap<T>(_ a: inout T, _ b: inout T) where T : ~Copyable
+// CHECK-MISC-NEXT: #else
+// CHECK-MISC-NOT: @_preInverseGenerics
+// CHECK-MISC-NEXT: public func old_swap<T>(_ a: inout T, _ b: inout T)
 // CHECK-MISC: #endif
 
+// CHECK-MISC: #if compiler(>=5.3) && $NoncopyableGenerics
+// CHECK-MISC-NEXT: @_preInverseGenerics public func borrowsNoncopyable<T>(_ t: borrowing T) where T : ~Copyable
+// CHECK-MISC-NEXT: #else
+// CHECK-MISC-NOT: @_preInverseGenerics
+// CHECK-MISC-NEXT: public func borrowsNoncopyable<T>(_ t: T)
+// CHECK-MISC-NEXT: #endif
+
 import Swiftskell
 
 // CHECK: #if compiler(>=5.3) && $NoncopyableGenerics