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diff --git a/test/CXX/temp/temp.deduct.guide/p3.cpp b/test/CXX/temp/temp.deduct.guide/p3.cpp
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+++ b/test/CXX/temp/temp.deduct.guide/p3.cpp
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+// RUN: %clang_cc1 -std=c++1z %s -verify
+
+// The same restrictions apply to the parameter-declaration-clause of a
+// deduction guide as in a function declaration.
+template<typename T> struct A {};
+A(void) -> A<int>; // ok
+A(void, int) -> A<int>; // expected-error {{'void' must be the first and only parameter if specified}}
+
+// We interpret this as also extending to the validity of redeclarations. It's
+// a bit of a stretch (OK, a lot of a stretch) but it gives desirable answers.
+A() -> A<int>; // ok, redeclaration
+
+A() -> A<int>; // expected-note {{previous}}
+A() -> A<float>; // FIXME: "functions" is a poor term. expected-error {{functions that differ only in their return type cannot be overloaded}}
+
+template<typename T> A(T) -> A<typename T::foo>;
+template<typename T> A(T) -> A<typename T::bar>; // ok, can overload on return type (SFINAE applies)
+
+A(long) -> A<int>;
+template<typename T = int> A(long) -> A<char>; // ok, non-template beats template as usual
+
+// (Pending DR) The template-name shall name a class template.
+template<typename T> using B = A<T>; // expected-note {{template}}
+B() -> B<int>; // expected-error {{cannot specify deduction guide for alias template 'B'}}
+// FIXME: expected-error@-1 {{declarator requires an identifier}}
+template<typename T> int C;
+C() -> int; // expected-error {{requires a type specifier}}
+template<typename T> void D();
+D() -> int; // expected-error {{requires a type specifier}}
+template<template<typename> typename TT> struct E { // expected-note 2{{template}}
+  // FIXME: Should only diagnose this once!
+  TT(int) -> TT<int>; // expected-error 2{{cannot specify deduction guide for template template parameter 'TT'}} expected-error {{requires an identifier}}
+};
+
+A(int) -> int; // expected-error {{deduced type 'int' of deduction guide is not a specialization of template 'A'}}
+template<typename T> A(T) -> B<T>; // expected-error {{deduced type 'B<T>' (aka 'A<type-parameter-0-0>') of deduction guide is not written as a specialization of template 'A'}}
+template<typename T> A(T*) -> const A<T>; // expected-error {{deduced type 'const A<T>' of deduction guide is not a specialization of template 'A'}}
+
+// A deduction-guide shall be declared in the same scope as the corresponding
+// class template.
+namespace WrongScope {
+  namespace {
+    template<typename T> struct AnonNS1 {}; // expected-note {{here}}
+    AnonNS1(float) -> AnonNS1<float>; // ok
+  }
+  AnonNS1(int) -> AnonNS1<int>; // expected-error {{deduction guide must be declared in the same scope as template 'WrongScope::}}
+  template<typename T> struct AnonNS2 {}; // expected-note {{here}}
+  namespace {
+    AnonNS1(char) -> AnonNS1<char>; // ok
+    AnonNS2(int) -> AnonNS2<int>; // expected-error {{deduction guide must be declared in the same scope as template 'WrongScope::AnonNS2'}}
+  }
+  namespace N {
+    template<typename T> struct NamedNS1 {}; // expected-note {{here}}
+    template<typename T> struct NamedNS2 {}; // expected-note {{here}}
+  }
+  using N::NamedNS1;
+  NamedNS1(int) -> NamedNS1<int>; // expected-error {{deduction guide must be declared in the same scope as template}}
+  using namespace N;
+  NamedNS2(int) -> NamedNS2<int>; // expected-error {{deduction guide must be declared in the same scope as template}}
+  struct ClassMemberA {
+    template<typename T> struct X {}; // expected-note {{here}}
+  };
+  struct ClassMemberB : ClassMemberA {
+    X(int) -> X<int>; // expected-error {{deduction guide must be declared in the same scope as template 'WrongScope::ClassMemberA::X'}}
+  };
+  template<typename T> struct Local {};
+  void f() {
+    Local(int) -> Local<int>; // expected-error 2{{expected}} expected-note {{to match}}
+    using WrongScope::Local;
+    Local(int) -> Local<int>; // expected-error 2{{expected}} expected-note {{to match}}
+  }
+}