ASTPrinter: Fix logic to determine if a requirement needs 'repeat' prefix

Author: slavapestov

lib/AST/ASTPrinter.cpp

@@ -804,7 +804,7 @@ class PrintAST : public ASTVisitor<PrintAST> {
 
   void printType(Type T) { printTypeWithOptions(T, Options); }
 
-  void printTransformedTypeWithOptions(Type T, PrintOptions options) {
+  Type getTransformedType(Type T) {
     if (CurrentType && Current && CurrentType->mayHaveMembers()) {
       auto *M = Current->getDeclContext()->getParentModule();
       SubstitutionMap subMap;
@@ -825,9 +825,16 @@ class PrintAST : public ASTVisitor<PrintAST> {
       }
 
       T = T.subst(subMap, SubstFlags::DesugarMemberTypes);
+    }
+
+    return T;
+  }
 
+  void printTransformedTypeWithOptions(Type T, PrintOptions options) {
+    T = getTransformedType(T);
+
+    if (CurrentType && Current && CurrentType->mayHaveMembers())
       options.TransformContext = TypeTransformContext(CurrentType);
-    }
 
     printTypeWithOptions(T, options);
   }
@@ -1833,6 +1840,11 @@ void PrintAST::printSingleDepthOfGenericSignature(
 }
 
 void PrintAST::printRequirement(const Requirement &req) {
+  SmallVector<Type, 2> rootParameterPacks;
+  getTransformedType(req.getFirstType())
+      ->getTypeParameterPacks(rootParameterPacks);
+  bool isPackRequirement = !rootParameterPacks.empty();
+
   switch (req.getKind()) {
   case RequirementKind::SameShape:
     Printer << "(repeat (";
@@ -1842,22 +1854,21 @@ void PrintAST::printRequirement(const Requirement &req) {
     Printer << ")) : Any";
     return;
   case RequirementKind::Layout:
-    if (req.getFirstType()->hasParameterPack())
+    if (isPackRequirement)
       Printer << "repeat ";
     printTransformedType(req.getFirstType());
     Printer << " : ";
     req.getLayoutConstraint()->print(Printer, Options);
     return;
   case RequirementKind::Conformance:
   case RequirementKind::Superclass:
-    if (req.getFirstType()->hasParameterPack())
+    if (isPackRequirement)
       Printer << "repeat ";
     printTransformedType(req.getFirstType());
     Printer << " : ";
     break;
   case RequirementKind::SameType:
-    if (req.getFirstType()->hasParameterPack() ||
-        req.getSecondType()->hasParameterPack())
+    if (isPackRequirement)
       Printer << "repeat ";
     printTransformedType(req.getFirstType());
     Printer << " == ";

test/ModuleInterface/pack_expansion_type.swift

@@ -2,6 +2,8 @@
 // RUN: %target-swift-emit-module-interface(%t/PackExpansionType.swiftinterface) %s -module-name PackExpansionType -disable-availability-checking
 // RUN: %FileCheck %s < %t/PackExpansionType.swiftinterface
 
+/// Requirements
+
 // CHECK: #if compiler(>=5.3) && $ParameterPacks
 // CHECK-NEXT: public func variadicFunction<each T, each U>(t: repeat each T, u: repeat each U) -> (repeat (each T, each U)) where (repeat (each T, each U)) : Any
 public func variadicFunction<each T, each U>(t: repeat each T, u: repeat each U) -> (repeat (each T, each U)) {}
@@ -24,6 +26,13 @@ public struct VariadicType<each T> {
 // CHECK: }
 // CHECK-NEXT: #endif
 
+// The second requirement should not be prefixed with 'repeat'
+// CHECK: public struct SameTypeReq<T, each U> where T : Swift.Sequence, T.Element == PackExpansionType.VariadicType<repeat each U> {
+public struct SameTypeReq<T: Sequence, each U> where T.Element == VariadicType<repeat each U> {}
+// CHECK: }
+
+/// Pack expansion types
+
 // CHECK: public func returnsVariadicType() -> PackExpansionType.VariadicType<>
 public func returnsVariadicType() -> VariadicType< > {}