Report C++20 concept declaration use

4 files changed, 61 insertions, 0 deletions

diff --git a/iwyu.cc b/iwyu.cc
index 478bcfc..dcf7b58 100644
--- a/iwyu.cc
+++ b/iwyu.cc
@@ -124,6 +124,7 @@
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ExprConcepts.h"
 #include "clang/AST/NestedNameSpecifier.h"
 #include "clang/AST/OperationKinds.h"
 #include "clang/AST/RecursiveASTVisitor.h"
@@ -163,6 +164,7 @@ using clang::CallExpr;
 using clang::ClassTemplateDecl;
 using clang::ClassTemplateSpecializationDecl;
 using clang::CompilerInstance;
+using clang::ConceptSpecializationExpr;
 using clang::ConstructorUsingShadowDecl;
 using clang::Decl;
 using clang::DeclContext;
@@ -4005,6 +4007,14 @@ class IwyuAstConsumer
     return Base::VisitUnaryExprOrTypeTraitExpr(expr);
   }
 
+  bool VisitConceptSpecializationExpr(ConceptSpecializationExpr* expr) {
+    if (CanIgnoreCurrentASTNode())
+      return true;
+    ReportDeclUse(CurrentLoc(), expr->getNamedConcept());
+    // TODO(bolshakov): analyze type parameter usage.
+    return Base::VisitConceptSpecializationExpr(expr);
+  }
+
   // --- Visitors of types derived from clang::Type.
 
   bool VisitTypedefType(clang::TypedefType* type) {
diff --git a/tests/cxx/concept-direct.h b/tests/cxx/concept-direct.h
new file mode 100644
index 0000000..4c8a707
--- /dev/null
+++ b/tests/cxx/concept-direct.h
@@ -0,0 +1,10 @@
+//===--- concept-direct.h - test input file for iwyu ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "tests/cxx/concept-indirect.h"
diff --git a/tests/cxx/concept-indirect.h b/tests/cxx/concept-indirect.h
new file mode 100644
index 0000000..d261003
--- /dev/null
+++ b/tests/cxx/concept-indirect.h
@@ -0,0 +1,11 @@
+//===--- concept-indirect.h - test input file for iwyu --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+template <typename>
+concept Concept = true;
diff --git a/tests/cxx/concept.cc b/tests/cxx/concept.cc
new file mode 100644
index 0000000..f20a3e6
--- /dev/null
+++ b/tests/cxx/concept.cc
@@ -0,0 +1,30 @@
+//===--- concept.cc - test input file for iwyu ----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// IWYU_ARGS: -I . --std=c++20
+
+// Tests C++20 concepts usage reporting.
+
+#include "tests/cxx/concept-direct.h"
+
+// IWYU: Concept is...*concept-indirect.h
+constexpr bool b = Concept<int>;
+
+/**** IWYU_SUMMARY
+
+tests/cxx/concept.cc should add these lines:
+#include "tests/cxx/concept-indirect.h"
+
+tests/cxx/concept.cc should remove these lines:
+- #include "tests/cxx/concept-direct.h"  // lines XX-XX
+
+The full include-list for tests/cxx/concept.cc:
+#include "tests/cxx/concept-indirect.h"  // for Concept
+
+***** IWYU_SUMMARY */