diff --git a/src/plugins/cppcheck/cppchecktool.h b/src/plugins/cppcheck/cppchecktool.h
index ff668cf40ea..203dc2edd27 100644
--- a/src/plugins/cppcheck/cppchecktool.h
+++ b/src/plugins/cppcheck/cppchecktool.h
@@ -49,7 +49,6 @@ class Project;
 namespace Cppcheck {
 namespace Internal {
 
-class Diagnostic;
 class CppcheckRunner;
 class CppcheckTextMarkManager;
 class CppcheckOptions;
diff --git a/src/plugins/cppcheck/cppchecktrigger.h b/src/plugins/cppcheck/cppchecktrigger.h
index 069bfc7b044..a745f232e38 100644
--- a/src/plugins/cppcheck/cppchecktrigger.h
+++ b/src/plugins/cppcheck/cppchecktrigger.h
@@ -42,10 +42,6 @@ class IDocument;
 class IEditor;
 }
 
-namespace CppTools {
-class ProjectInfo;
-}
-
 namespace Cppcheck {
 namespace Internal {