[c++2a] P0515R3: lexer support for new <=> token.

llvm-svn: 319509

1 files changed, 73 insertions, 0 deletions

diff --git a/clang/test/Lexer/cxx2a-spaceship.cpp b/clang/test/Lexer/cxx2a-spaceship.cpp
new file mode 100644
index 00000000000..f407937c4e3
--- /dev/null
+++ b/clang/test/Lexer/cxx2a-spaceship.cpp
@@ -0,0 +1,73 @@
+// RUN: %clang_cc1 -std=c++17 %s -verify
+// RUN: %clang_cc1 -std=c++2a %s -verify
+// RUN: %clang_cc1 -std=c++2a %s -verify -Wc++17-compat -DCOMPAT
+//
+// RUN: %clang_cc1 -std=c++17 %s -E -o - | FileCheck %s --check-prefix=CXX17
+// RUN: %clang_cc1 -std=c++2a %s -E -o - | FileCheck %s --check-prefix=CXX20
+
+namespace N {
+
+struct A {};
+void operator<=(A, A);
+#if __cplusplus > 201703L
+void operator<=>(A, A); // expected-error {{}}
+#ifdef COMPAT
+// expected-warning@-2 {{'<=>' operator is incompatible with C++ standards before C++2a}}
+#endif
+#endif
+
+template<auto> struct X {};
+X<operator<=>
+#if __cplusplus <= 201703L
+  // expected-warning@-2 {{'<=>' is a single token in C++2a; add a space to avoid a change in behavior}}
+#else
+  > // expected-error@-4 {{}}
+#endif
+#ifdef COMPAT
+// expected-warning@-7 {{'<=>' operator is incompatible with C++ standards before C++2a}}
+#endif
+  x;
+}
+
+// <=> can be formed by pasting other comparison operators.
+#if __cplusplus > 201703L
+#define STR(x) #x
+#define STR_EXPANDED(x) STR(x)
+#define PASTE(x, y) x ## y
+constexpr char a[] = STR_EXPANDED(PASTE(<, =>));
+constexpr char b[] = STR_EXPANDED(PASTE(<=, >));
+static_assert(__builtin_strcmp(a, "<=>") == 0);
+static_assert(__builtin_strcmp(b, "<=>") == 0);
+#endif
+
+// -E must not accidentally form a <=> token.
+
+// CXX17: preprocess1: < =>
+// CXX17: preprocess2: <=>
+// CXX17: preprocess3: < =>
+// CXX17: preprocess4: <=>=
+// CXX17: preprocess5: <=>>
+// CXX17: preprocess6: <=>>=
+// CXX17: preprocess7: <=>
+// CXX17: preprocess8: <=>=
+//
+// CXX20: preprocess1: < =>
+// CXX20: preprocess2: <= >
+// CXX20: preprocess3: < =>
+// CXX20: preprocess4: <= >=
+// CXX20: preprocess5: <= >>
+// CXX20: preprocess6: <= >>=
+// CXX20: preprocess7: <=>
+// CXX20: preprocess8: <=>=
+
+#define ID(x) x
+[[some_vendor::some_attribute( // expected-warning {{unknown attribute}}
+preprocess1: ID(<)ID(=>),
+preprocess2: ID(<=)ID(>),
+preprocess3: ID(<)ID(=)ID(>),
+preprocess4: ID(<=)ID(>=),
+preprocess5: ID(<=)ID(>>),
+preprocess6: ID(<=)ID(>>=),
+preprocess7: ID(<=>) // expected-warning 0-1{{'<=>'}}
+preprocess8: ID(<=>=) // expected-warning 0-1{{'<=>'}}
+)]];