[ASTPrinter] Account for contextual where clauses when printing gen. …

lib/AST/ASTPrinter.cpp

@@ -826,7 +826,7 @@ class PrintAST : public ASTVisitor<PrintAST> {
   void printMembers(ArrayRef<Decl *> members, bool needComma = false,
                     bool openBracket = true, bool closeBracket = true);
   void printGenericDeclGenericParams(GenericContext *decl);
-  void printGenericDeclGenericRequirements(GenericContext *decl);
+  void printDeclGenericRequirements(GenericContext *decl);
   void printInherited(const Decl *decl);
   void printBodyIfNecessary(const AbstractFunctionDecl *decl);
 
@@ -2055,19 +2055,23 @@ void PrintAST::printGenericDeclGenericParams(GenericContext *decl) {
       printGenericSignature(GenericSig, PrintParams | InnermostOnly);
 }
 
-void PrintAST::printGenericDeclGenericRequirements(GenericContext *decl) {
-  if (decl->isGeneric()) {
-    if (auto genericSig = decl->getGenericSignature()) {
-      auto baseGenericSig = decl->getParent()
-          ->getGenericSignatureOfContext();
-      printGenericSignature(genericSig, PrintRequirements,
-                            [baseGenericSig](const Requirement &req) {
-                              if (baseGenericSig)
-                                return !baseGenericSig->isRequirementSatisfied(req);
-                              return true;
-                            });
-    }
-  }
+void PrintAST::printDeclGenericRequirements(GenericContext *decl) {
+  const auto genericSig = decl->getGenericSignature();
+  if (!genericSig)
+    return;
+
+  // If the declaration is itself non-generic, it might still
+  // carry a contextual where clause.
+  const auto parentSig = decl->getParent()->getGenericSignatureOfContext();
+  if (parentSig && parentSig->isEqual(genericSig))
+    return;
+
+  printGenericSignature(genericSig, PrintRequirements,
+                        [parentSig](const Requirement &req) {
+                          if (parentSig)
+                            return !parentSig->isRequirementSatisfied(req);
+                          return true;
+                        });
 }
 
 void PrintAST::printInherited(const Decl *decl) {
@@ -2178,7 +2182,7 @@ void PrintAST::printSynthesizedExtension(Type ExtendedType,
 
     printExtendedTypeName(ExtendedType, Printer, Options);
     printInherited(ExtDecl);
-    printGenericDeclGenericRequirements(ExtDecl);
+    printDeclGenericRequirements(ExtDecl);
   }
   if (Options.TypeDefinitions) {
     printMembersOfDecl(ExtDecl, false,
@@ -2379,7 +2383,7 @@ void PrintAST::visitTypeAliasDecl(TypeAliasDecl *decl) {
     llvm::SaveAndRestore<GenericEnvironment*> setGenericEnv(Options.GenericEnv,
                                                 decl->getGenericEnvironment());
     printTypeLoc(TypeLoc(decl->getUnderlyingTypeRepr(), Ty));
-    printGenericDeclGenericRequirements(decl);
+    printDeclGenericRequirements(decl);
   }
 }
 
@@ -2434,7 +2438,7 @@ void PrintAST::visitEnumDecl(EnumDecl *decl) {
         printGenericDeclGenericParams(decl);
       });
     printInherited(decl);
-    printGenericDeclGenericRequirements(decl);
+    printDeclGenericRequirements(decl);
   }
   if (Options.TypeDefinitions) {
     printMembersOfDecl(decl, false, true,
@@ -2462,7 +2466,7 @@ void PrintAST::visitStructDecl(StructDecl *decl) {
         printGenericDeclGenericParams(decl);
       });
     printInherited(decl);
-    printGenericDeclGenericRequirements(decl);
+    printDeclGenericRequirements(decl);
   }
   if (Options.TypeDefinitions) {
     printMembersOfDecl(decl, false, true,
@@ -2491,7 +2495,7 @@ void PrintAST::visitClassDecl(ClassDecl *decl) {
       });
 
     printInherited(decl);
-    printGenericDeclGenericRequirements(decl);
+    printDeclGenericRequirements(decl);
   }
 
   if (Options.TypeDefinitions) {
@@ -2930,7 +2934,7 @@ void PrintAST::visitFuncDecl(FuncDecl *decl) {
           ResultTyLoc, decl->isImplicitlyUnwrappedOptional());
       Printer.printStructurePost(PrintStructureKind::FunctionReturnType);
     }
-    printGenericDeclGenericRequirements(decl);
+    printDeclGenericRequirements(decl);
   }
 
   printBodyIfNecessary(decl);
@@ -3079,7 +3083,7 @@ void PrintAST::visitSubscriptDecl(SubscriptDecl *decl) {
   printTypeLocForImplicitlyUnwrappedOptional(
     elementTy, decl->isImplicitlyUnwrappedOptional());
   Printer.printStructurePost(PrintStructureKind::FunctionReturnType);
-  printGenericDeclGenericRequirements(decl);
+  printDeclGenericRequirements(decl);
   printAccessors(decl);
 }
 
@@ -3127,7 +3131,7 @@ void PrintAST::visitConstructorDecl(ConstructorDecl *decl) {
       printFunctionParameters(decl);
     });
 
-  printGenericDeclGenericRequirements(decl);
+  printDeclGenericRequirements(decl);
 
   printBodyIfNecessary(decl);
 }

test/IDE/print_ast_tc_decls.swift

@@ -1217,6 +1217,21 @@ struct GenericParams1<
 // FIXME: in protocol compositions protocols are listed in reverse order.
 //
 // PASS_ONE_LINE_TYPEREPR-DAG: {{^}}  func genericParams1<GenericFoo, GenericFooX, GenericBar, GenericBaz>(a: StructGenericFoo, b: StructGenericBar, c: StructGenericBaz, d: GenericFoo, e: GenericFooX, f: GenericBar, g: GenericBaz) where GenericFoo : FooProtocol, GenericFooX : FooClass, GenericBar : BarProtocol, GenericBar : FooProtocol{{$}}
+
+  func contextualWhereClause1() where StructGenericBaz == Never {}
+  // PASS_PRINT_AST: func contextualWhereClause1() where StructGenericBaz == Never{{$}}
+
+  subscript(index: Int) -> Never where StructGenericBaz: FooProtocol {
+    return fatalError()
+  }
+  // PASS_PRINT_AST: subscript(index: Int) -> Never where StructGenericBaz : FooProtocol { get }{{$}}
+}
+extension GenericParams1 where StructGenericBaz: FooProtocol {
+  static func contextualWhereClause2() where StructGenericBaz: FooClass {}
+  // PASS_PRINT_AST: static func contextualWhereClause2() where StructGenericBaz : FooClass{{$}}
+
+  typealias ContextualWhereClause3 = Never where StructGenericBaz: QuxProtocol, StructGenericBaz.Qux == Void
+  // PASS_PRINT_AST: typealias ContextualWhereClause3 = Never where StructGenericBaz : QuxProtocol, StructGenericBaz.Qux == Void{{$}}
 }
 
 struct GenericParams2<T : FooProtocol> where T : BarProtocol {}