ASTDemangler: Correctly demangle generic signature of nominal type in constrained extension

Author: slavapestov

lib/AST/ASTDemangler.cpp

@@ -1011,12 +1011,8 @@ LayoutConstraint ASTBuilder::getLayoutConstraintWithSizeAlign(
 CanGenericSignature ASTBuilder::demangleGenericSignature(
     NominalTypeDecl *nominalDecl,
     NodePointer node) {
-  // The type parameters appearing in the signature's requirements are not
-  // notionally part of our current generic signature.
-  //
-  // FIXME: Fix this to support variadic generics.
   llvm::SaveAndRestore<GenericSignature> savedSignature(
-      GenericSig, GenericSignature());
+      GenericSig, nominalDecl->getGenericSignature());
 
   SmallVector<Requirement, 2> requirements;
 

test/TypeDecoder/variadic_nominal_types.swift

@@ -0,0 +1,57 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift -emit-executable %s -g -o %t/variadic_nominal_types -emit-module -enable-experimental-feature VariadicGenerics
+
+// RUN: sed -ne '/\/\/ *DEMANGLE-TYPE: /s/\/\/ *DEMANGLE-TYPE: *//p' < %s > %t/input
+// RUN: %lldb-moduleimport-test-with-sdk %t/variadic_nominal_types -type-from-mangled=%t/input | %FileCheck %s --check-prefix=CHECK-TYPE
+
+// Because of -enable-experimental-feature VariadicGenerics
+// REQUIRES: asserts
+
+struct Variadic<T..., U> {
+  struct Inner<V..., W> {}
+}
+
+extension Variadic where each T: Equatable {
+  struct Constrained {}
+}
+
+func blackHole(_: Any...) {}
+
+do {
+  let x0 = Variadic<Float>()
+  let x1 = Variadic<Int, Float>()
+  let x2 = Variadic<Int, String, Float>()
+  let x3 = Variadic<Int, String, Float>.Inner<Character, Bool, Double>()
+
+  blackHole(x0, x1, x2, x3)
+}
+
+do {
+  let x0 = Variadic<Float>.Constrained()
+  let x1 = Variadic<Int, Float>.Constrained()
+  let x2 = Variadic<Int, String, Float>.Constrained()
+
+  blackHole(x0, x1, x2)
+}
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicVyyQPSfGD
+// CHECK-TYPE: Variadic<Float>
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicVySi_QPSfGD
+// CHECK-TYPE: Variadic<Int, Float>
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicVySi_SSQPSfGD
+// CHECK-TYPE: Variadic<Int, String, Float>
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicV5InnerVySi_SSQPSf_SJ_SbQPSdGD
+// CHECK-TYPE: Variadic<Int, String, Float>.Inner<Character, Bool, Double>
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicVAASQRzrlE11ConstrainedVyyQPSf_GD
+// CHECK-TYPE: Variadic<Float>.Constrained
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicVAASQRzrlE11ConstrainedVySi_QPSf_GD
+// CHECK-TYPE: Variadic<Int, Float>.Constrained
+
+// DEMANGLE-TYPE: $s22variadic_nominal_types8VariadicVAASQRzrlE11ConstrainedVySi_SSQPSf_GD
+// CHECK-TYPE: Variadic<Int, String, Float>.Constrained