diff --git a/AI/VCAI/Fuzzy.h b/AI/VCAI/Fuzzy.h
index 7c45e8d63..219390f69 100644
--- a/AI/VCAI/Fuzzy.h
+++ b/AI/VCAI/Fuzzy.h
@@ -15,7 +15,7 @@
 class VCAI;
 class CArmedInstance;
 class CBank;
-class SectorMap;
+struct SectorMap;
 
 class engineBase
 {
diff --git a/AI/VCAI/Goals.h b/AI/VCAI/Goals.h
index 876c8e574..d9602c663 100644
--- a/AI/VCAI/Goals.h
+++ b/AI/VCAI/Goals.h
@@ -21,7 +21,7 @@ class FuzzyHelper;
 
 namespace Goals
 {
-	struct AbstractGoal;
+	class AbstractGoal;
 	class VisitTile;
 	typedef std::shared_ptr<Goals::AbstractGoal> TSubgoal;
 	typedef std::vector<TSubgoal> TGoalVec;
diff --git a/lib/filesystem/FileStream.cpp b/lib/filesystem/FileStream.cpp
index 2bb7019ee..b61350420 100644
--- a/lib/filesystem/FileStream.cpp
+++ b/lib/filesystem/FileStream.cpp
@@ -272,7 +272,7 @@ zlib_filefunc64_def* FileStream::GetMinizipFilefunc()
 	return &MinizipFilefunc;
 }
 
-template class boost::iostreams::stream<FileBuf>;
+template struct boost::iostreams::stream<FileBuf>;
 
 /*static*/
 bool FileStream::CreateFile(const boost::filesystem::path& filename)
diff --git a/lib/filesystem/FileStream.h b/lib/filesystem/FileStream.h
index 0ef276174..b0c90c2f2 100644
--- a/lib/filesystem/FileStream.h
+++ b/lib/filesystem/FileStream.h
@@ -37,7 +37,7 @@ struct zlib_filefunc64_def_s;
 typedef zlib_filefunc64_def_s zlib_filefunc64_def;
 
 #ifdef VCMI_DLL
-extern template class DLL_LINKAGE boost::iostreams::stream<FileBuf>;
+extern template struct DLL_LINKAGE boost::iostreams::stream<FileBuf>;
 #endif
 
 class DLL_LINKAGE FileStream : public boost::iostreams::stream<FileBuf>