[C++20] Implement context-sensitive header-name lexing and pp-import parsing in the preprocessor.

llvm-svn: 358231

1 files changed, 33 insertions, 0 deletions

diff --git a/clang/test/CXX/cpp/cpp.module/p2.cpp b/clang/test/CXX/cpp/cpp.module/p2.cpp
new file mode 100644
index 00000000000..ae68a508a02
--- /dev/null
+++ b/clang/test/CXX/cpp/cpp.module/p2.cpp
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -std=c++2a -emit-header-module -fmodule-name=attrs -x c++-header %S/Inputs/empty.h %S/Inputs/attrs.h -o %t.pcm
+// RUN: %clang_cc1 -std=c++2a %s -fmodule-file=%t.pcm -fsyntax-only -verify -I%S/Inputs
+
+template<int> struct import; // expected-note 2{{previous}}
+constexpr struct { int h; } empty = {0};
+struct A;
+struct B;
+struct C;
+template<> struct import<0> {
+  static A a;
+  static B b;
+  static C c;
+};
+
+// OK, not an import-declaration.
+// FIXME: This is valid, see PR41192
+struct A {} // FIXME expected-error {{expected ';'}}
+::import
+<empty.h>::a; // FIXME expected-error {{requires a type specifier}}
+
+// This is invalid: the tokens after 'import' are a header-name, so cannot be
+// parsed as a template-argument-list.
+struct B {}
+import // expected-error {{redefinition of 'import'}} expected-error {{expected ';'}}
+<empty.h>::b; // (error recovery skips these tokens)
+
+// Likewise, this is ill-formed after the tokens are reconstituted into a
+// header-name token.
+struct C {}
+import // expected-error {{redefinition of 'import'}} expected-error {{expected ';'}}
+<
+empty.h // (error recovery skips these tokens)
+>::c;