Revert concepts changes from D41910

These changes caused LibcxxVariantDataFormatterTestCase in lldb to fail
with an assert:

Assertion failed: (Idx < size() && "Out-of-bounds Bit access."),
function operator[], file
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/llvm/include/llvm/ADT/SmallBitVector.h,
line 452.

In:

7  clang-10                 0x00000001094b79d9 isAtLeastAsSpecializedAs(clang::Sema&, clang::SourceLocation, clang::FunctionTemplateDecl*, clang::FunctionTemplateDecl*, clang::TemplatePartialOrderingContext, unsigned int) + 1865
8  clang-10                 0x00000001094b7111 clang::Sema::getMoreSpecializedTemplate(clang::FunctionTemplateDecl*, clang::FunctionTemplateDecl*, clang::SourceLocation, clang::TemplatePartialOrderingContext, unsigned int, unsigned int) + 97
9  clang-10                 0x000000010939bf88 clang::isBetterOverloadCandidate(clang::Sema&, clang::OverloadCandidate const&, clang::OverloadCandidate const&, clang::SourceLocation, clang::OverloadCandidateSet::CandidateSetKind) + 1128

Revert "[Concepts] Fix incorrect move out of temporary in D41910"

This reverts commit 11d5fa6e87e3584f72056ecc2b17f88c58323dde.

Revert "[Concepts] Fix crash in D41910"

This reverts commit 12038be20ee6a903cdbd3fddce65535ef683e31d.

Revert "[Concepts] Constrained partial specializations and function overloads."

This reverts commit fc0731b98a67c793862288f8ae334322666214dc.

5 files changed, 5 insertions, 213 deletions

diff --git a/clang/test/CXX/expr/expr.prim/expr.prim.id/p3.cpp b/clang/test/CXX/expr/expr.prim/expr.prim.id/p3.cpp
index fb3978240af..1e10d4550ce 100644
--- a/clang/test/CXX/expr/expr.prim/expr.prim.id/p3.cpp
+++ b/clang/test/CXX/expr/expr.prim/expr.prim.id/p3.cpp
@@ -75,8 +75,11 @@ static_assert(!IsTypePredicate<T1>);
 template<typename T, typename U, typename... Ts>
 concept OneOf = (Same<T, Ts> || ...);
 
-static_assert(OneOf<int, long, int>);
-static_assert(!OneOf<long, int, char, char>);
+template<typename... X>
+constexpr bool S = OneOf<X..., int, int>;
+
+static_assert(S<int, long, int>);
+static_assert(!S<long, int, char, char>);
 
 namespace piecewise_substitution {
   template <typename T>
@@ -175,11 +178,3 @@ template<typename T> concept AccessPrivate = T{}.f;
 static_assert(AccessPrivate<T4>);
 // expected-error@-1{{static_assert failed}}
 // expected-note@-2{{because 'T4' does not satisfy 'AccessPrivate'}}
-
-template<typename T, typename U>
-// expected-note@-1{{template parameter is declared here}}
-concept C8 = sizeof(T) > sizeof(U);
-
-template<typename... T>
-constexpr bool B8 = C8<T...>;
-// expected-error@-1{{pack expansion used as argument for non-pack parameter of concept}}
diff --git a/clang/test/CXX/temp/temp.constr/temp.constr.normal/p1.cpp b/clang/test/CXX/temp/temp.constr/temp.constr.normal/p1.cpp
deleted file mode 100644
index 387b75c4ef0..00000000000
--- a/clang/test/CXX/temp/temp.constr/temp.constr.normal/p1.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-// RUN: %clang_cc1 -std=c++2a -fconcepts-ts -x c++ -verify %s
-
-template<typename T> concept True = true;
-template<typename T> concept Foo = True<T*>;
-template<typename T> concept Bar = Foo<T&>;
-template<typename T> requires Bar<T> struct S { };
-template<typename T> requires Bar<T> && true struct S<T> { };
-
-template<typename T> concept True2 = sizeof(T) >= 0;
-template<typename T> concept Foo2 = True2<T*>;
-// expected-error@-1{{'type name' declared as a pointer to a reference of type 'type-parameter-0-0 &'}}
-template<typename T> concept Bar2 = Foo2<T&>;
-// expected-note@-1{{while substituting into concept arguments here; substitution failures not allowed in concept arguments}}
-template<typename T> requires Bar2<T> struct S2 { };
-// expected-note@-1{{template is declared here}}
-template<typename T> requires Bar2<T> && true struct S2<T> { };
-// expected-error@-1{{class template partial specialization is not more specialized than the primary template}}
-// expected-note@-2{{while calculating associated constraint of template 'S2' here}}
diff --git a/clang/test/CXX/temp/temp.constr/temp.constr.order/class-template-partial-specializations.cpp b/clang/test/CXX/temp/temp.constr/temp.constr.order/class-template-partial-specializations.cpp
deleted file mode 100644
index 8c2f5526941..00000000000
--- a/clang/test/CXX/temp/temp.constr/temp.constr.order/class-template-partial-specializations.cpp
+++ /dev/null
@@ -1,50 +0,0 @@
-// RUN: %clang_cc1 -std=c++2a -fconcepts-ts -x c++ -verify %s
-
-template<typename T> requires sizeof(T) >= 4
-class A{}; // expected-note{{template is declared here}}
-
-template<typename T> requires sizeof(T) >= 4 && sizeof(T) <= 10
-class A<T>{}; // expected-error{{class template partial specialization is not more specialized than the primary template}}
-
-template<typename T>
-concept C1 = sizeof(T) >= 4;
-
-template<typename T> requires C1<T>
-class B{};
-
-template<typename T> requires C1<T> && sizeof(T) <= 10
-class B<T>{};
-
-template<typename T>
-concept C2 = sizeof(T) > 1 && sizeof(T) <= 8;
-
-template<typename T>
-class C{};
-
-template<typename T> requires C1<T>
-class C<T>{};
-
-template<typename T>
-class D{}; // expected-note{{previous definition is here}}
-
-template<typename T>
-class D<T>{}; // expected-error{{class template partial specialization does not specialize any template argument; to define the primary template, remove the template argument list}} expected-error{{redefinition of 'D'}}
-
-template<typename T> requires C1<T> // expected-note{{previous template declaration is here}}
-class E{};
-
-template<typename T> // expected-error{{requires clause differs in template redeclaration}}
-class E<T>{}; // expected-error{{class template partial specialization does not specialize any template argument; to define the primary template, remove the template argument list}}
-
-template<typename T>
-struct F{ enum{ value = 1 }; };
-
-template<typename T> requires C1<T> && C2<T>
-struct F<T>{ enum{ value = 2 }; };
-
-template<typename T> requires C1<T> || C2<T>
-struct F<T>{ enum{ value = 3 }; };
-
-static_assert(F<unsigned>::value == 2);
-static_assert(F<char[10]>::value == 3);
-static_assert(F<char>::value == 1);
diff --git a/clang/test/CXX/temp/temp.constr/temp.constr.order/function-templates.cpp b/clang/test/CXX/temp/temp.constr/temp.constr.order/function-templates.cpp
deleted file mode 100644
index d1b52182df4..00000000000
--- a/clang/test/CXX/temp/temp.constr/temp.constr.order/function-templates.cpp
+++ /dev/null
@@ -1,82 +0,0 @@
-// RUN: %clang_cc1 -std=c++2a -fconcepts-ts -x c++ -verify %s
-
-template<typename T> requires sizeof(T) >= 4
-bool a() { return false; } // expected-note {{candidate function [with T = unsigned int]}}
-
-template<typename T> requires sizeof(T) >= 4 && sizeof(T) <= 10
-bool a() { return true; } // expected-note {{candidate function [with T = unsigned int]}}
-
-bool av = a<unsigned>(); // expected-error {{call to 'a' is ambiguous}}
-
-template<typename T>
-concept C1 = sizeof(T) >= 4;
-
-template<typename T> requires C1<T>
-constexpr bool b() { return false; }
-
-template<typename T> requires C1<T> && sizeof(T) <= 10
-constexpr bool b() { return true; }
-
-static_assert(b<int>());
-static_assert(!b<int[10]>());
-
-template<typename T>
-concept C2 = sizeof(T) > 1 && sizeof(T) <= 8;
-
-template<typename T>
-bool c() { return false; }
-
-template<typename T> requires C1<T>
-bool c() { return true; }
-
-template<typename T> requires C1<T>
-constexpr bool d() { return false; }
-
-template<typename T>
-constexpr bool d() { return true; }
-
-static_assert(!d<int>());
-
-template<typename T>
-constexpr int e() { return 1; }
-
-template<typename T> requires C1<T> && C2<T>
-constexpr int e() { return 2; }
-
-template<typename T> requires C1<T> || C2<T>
-constexpr int e() { return 3; }
-
-static_assert(e<unsigned>() == 2);
-static_assert(e<char[10]>() == 3);
-static_assert(e<char>() == 1);
-
-template<class T, class U>
-concept BiggerThan = sizeof(T) > sizeof(U);
-
-template<class T>
-concept BiggerThanInt = BiggerThan<T, int>;
-
-template<class T, class U> requires BiggerThan<T, U>
-void f() { }
-// expected-note@-1 {{candidate function [with T = long long, U = int]}}
-
-template<class T, class U> requires BiggerThanInt<T>
-void f() { }
-// expected-note@-1 {{candidate function [with T = long long, U = int]}}
-
-static_assert(sizeof(f<long long, int>()));
-// expected-error@-1 {{call to 'f' is ambiguous}}
-
-template<typename T>
-concept C3 = true;
-
-template<typename T>
-concept C4 = true && C3<T>;
-
-template<typename T> requires C3<void>
-int g() { }
-
-template<typename T> requires C4<void>
-int g() { }
-
-static_assert(sizeof(g<int>()));
\ No newline at end of file
diff --git a/clang/test/CXX/temp/temp.constr/temp.constr.order/var-template-partial-specializations.cpp b/clang/test/CXX/temp/temp.constr/temp.constr.order/var-template-partial-specializations.cpp
deleted file mode 100644
index b40c77e70a1..00000000000
--- a/clang/test/CXX/temp/temp.constr/temp.constr.order/var-template-partial-specializations.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-// RUN: %clang_cc1 -std=c++2a -fconcepts-ts -x c++ -verify %s
-
-template<typename T> requires sizeof(T) >= 4
-bool a = false; // expected-note{{template is declared here}}
-
-template<typename T> requires sizeof(T) >= 4 && sizeof(T) <= 10
-bool a<T> = true; // expected-error{{variable template partial specialization is not more specialized than the primary template}}
-
-template<typename T>
-concept C1 = sizeof(T) >= 4;
-
-template<typename T> requires C1<T>
-bool b = false;
-
-template<typename T> requires C1<T> && sizeof(T) <= 10
-bool b<T> = true;
-
-template<typename T>
-concept C2 = sizeof(T) > 1 && sizeof(T) <= 8;
-
-template<typename T>
-bool c = false;
-
-template<typename T> requires C1<T>
-bool c<T> = true;
-
-template<typename T>
-bool d = false;
-
-template<typename T>
-bool d<T> = true; // expected-error{{variable template partial specialization does not specialize any template argument; to define the primary template, remove the template argument list}}
-
-template<typename T> requires C1<T>
-bool e = false;
-
-template<typename T>
-bool e<T> = true; // expected-error{{variable template partial specialization does not specialize any template argument; to define the primary template, remove the template argument list}}
-
-template<typename T>
-constexpr int f = 1;
-
-template<typename T> requires C1<T> && C2<T>
-constexpr int f<T> = 2;
-
-template<typename T> requires C1<T> || C2<T>
-constexpr int f<T> = 3;
-
-static_assert(f<unsigned> == 2);
-static_assert(f<char[10]> == 3);
-static_assert(f<char> == 1);
-
-
-