diff --git a/src/CppParser/Parser.cpp b/src/CppParser/Parser.cpp
index 4c90c7e5..53b06e3b 100644
--- a/src/CppParser/Parser.cpp
+++ b/src/CppParser/Parser.cpp
@@ -70,6 +70,8 @@ void* IgnorePtr = reinterpret_cast<void*>(0x1);
 
 Parser::Parser(CppParserOptions* Opts) : lib(Opts->ASTContext), opts(Opts), index(0)
 {
+    supportedStdTypes.insert("allocator");
+    supportedStdTypes.insert("basic_string");
 }
 
 LayoutField Parser::WalkVTablePointer(Class* Class,
@@ -821,14 +823,14 @@ Class* Parser::WalkRecordCXX(const clang::CXXRecordDecl* Record)
 static int I = 0;
 
 static bool IsRecordValid(const clang::RecordDecl* RC,
-    std::vector<const clang::RecordDecl*>& Visited)
+    std::unordered_set<const clang::RecordDecl*>& Visited)
 {
     using namespace clang;
 
-    if (std::find(Visited.begin(), Visited.end(), RC) != Visited.end())
+    if (Visited.find(RC) != Visited.end())
         return true;
 
-    Visited.push_back(RC);
+    Visited.insert(RC);
     if (RC->isInvalidDecl())
         return false;
     for (auto Field : RC->fields())
@@ -845,7 +847,7 @@ static bool IsRecordValid(const clang::RecordDecl* RC,
 
 static bool IsRecordValid(const clang::RecordDecl* RC)
 {
-    std::vector<const clang::RecordDecl*> Visited;
+    std::unordered_set<const clang::RecordDecl*> Visited;
     return IsRecordValid(RC, Visited);
 }
 
@@ -881,6 +883,23 @@ static bool HasLayout(const clang::RecordDecl* Record)
     return true;
 }
 
+bool Parser::IsSupported(const clang::RecordDecl* RD)
+{
+    return !c->getSourceManager().isInSystemHeader(RD->getLocStart()) ||
+        supportedStdTypes.find(RD->getName()) != supportedStdTypes.end();
+}
+
+bool Parser::IsSupported(const clang::CXXMethodDecl* MD)
+{
+    using namespace clang;
+
+    return !c->getSourceManager().isInSystemHeader(MD->getLocStart()) ||
+        isa<CXXConstructorDecl>(MD) || isa<CXXDestructorDecl>(MD) ||
+        (MD->getName() == "c_str" &&
+         supportedStdTypes.find(MD->getParent()->getName()) !=
+            supportedStdTypes.end());
+}
+
 void Parser::WalkRecord(const clang::RecordDecl* Record, Class* RC)
 {
     using namespace clang;
@@ -920,11 +939,15 @@ void Parser::WalkRecord(const clang::RecordDecl* Record, Class* RC)
         ReadClassLayout(RC, Record, CharUnits(), true);
     }
 
-    for(auto it = Record->decls_begin(); it != Record->decls_end(); ++it)
-    {
-        auto D = *it;
+    for (auto FD : Record->fields())
+        WalkFieldCXX(FD, RC);
+
+    if (!IsSupported(Record))
+        return;
 
-        switch(D->getKind())
+    for (auto D : Record->decls())
+    {
+        switch (D->getKind())
         {
         case Decl::CXXConstructor:
         case Decl::CXXDestructor:
@@ -932,13 +955,8 @@ void Parser::WalkRecord(const clang::RecordDecl* Record, Class* RC)
         case Decl::CXXMethod:
         {
             auto MD = cast<CXXMethodDecl>(D);
-            WalkMethodCXX(MD);
-            break;
-        }
-        case Decl::Field:
-        {
-            auto FD = cast<FieldDecl>(D);
-            WalkFieldCXX(FD, RC);
+            if (IsSupported(MD))
+                WalkMethodCXX(MD);
             break;
         }
         case Decl::AccessSpec:
@@ -954,6 +972,7 @@ void Parser::WalkRecord(const clang::RecordDecl* Record, Class* RC)
             RC->Specifiers.push_back(AccessDecl);
             break;
         }
+        case Decl::Field: // fields already handled
         case Decl::IndirectField: // FIXME: Handle indirect fields
             break;
         case Decl::CXXRecord:
diff --git a/src/CppParser/Parser.h b/src/CppParser/Parser.h
index 2f85375c..d3d47558 100644
--- a/src/CppParser/Parser.h
+++ b/src/CppParser/Parser.h
@@ -21,6 +21,7 @@
 #include "CppParser.h"
 
 #include <string>
+#include <unordered_set>
 
 namespace clang {
   namespace CodeGen {
@@ -59,6 +60,8 @@ public:
     ParserTargetInfo*  GetTargetInfo();
 
 private:
+    bool IsSupported(const clang::RecordDecl* RD);
+    bool IsSupported(const clang::CXXMethodDecl* MD);
     // AST traversers
     void WalkAST();
     Declaration* WalkDeclaration(const clang::Decl* D);
@@ -143,6 +146,12 @@ private:
     void HandleComments(const clang::Decl* D, Declaration* Decl);
     void HandleDiagnostics(ParserResult* res);
 
+    ParserResultKind ReadSymbols(llvm::StringRef File,
+                                 llvm::object::basic_symbol_iterator Begin,
+                                 llvm::object::basic_symbol_iterator End,
+                                 CppSharp::CppParser::NativeLibrary*& NativeLib);
+    Declaration* GetDeclarationFromFriend(clang::NamedDecl* FriendDecl);
+
     int index;
     CppSharp::CppParser::AST::ASTContext* lib;
     CppParserOptions* opts;
@@ -153,12 +162,7 @@ private:
     std::unordered_map<const clang::TemplateTypeParmDecl*, TypeTemplateParameter*> walkedTypeTemplateParameters;
     std::unordered_map<const clang::TemplateTemplateParmDecl*, TemplateTemplateParameter*> walkedTemplateTemplateParameters;
     std::unordered_map<const clang::NonTypeTemplateParmDecl*, NonTypeTemplateParameter*> walkedNonTypeTemplateParameters;
-
-    ParserResultKind ReadSymbols(llvm::StringRef File,
-                                 llvm::object::basic_symbol_iterator Begin,
-                                 llvm::object::basic_symbol_iterator End,
-                                 CppSharp::CppParser::NativeLibrary*& NativeLib);
-    Declaration* GetDeclarationFromFriend(clang::NamedDecl* FriendDecl);
+    std::unordered_set<std::string> supportedStdTypes;
 };
 
 } }
\ No newline at end of file
diff --git a/src/Generator.Tests/AST/TestAST.cs b/src/Generator.Tests/AST/TestAST.cs
index 4a7a2f59..3bed5441 100644
--- a/src/Generator.Tests/AST/TestAST.cs
+++ b/src/Generator.Tests/AST/TestAST.cs
@@ -303,13 +303,13 @@ namespace CppSharp.Generator.Tests.AST
         [Test]
         public void TestLineNumber()
         {
-            Assert.AreEqual(72, AstContext.FindClass("HiddenInNamespace").First().LineNumberStart);
+            Assert.AreEqual(70, AstContext.FindClass("HiddenInNamespace").First().LineNumberStart);
         }
 
         [Test]
         public void TestLineNumberOfFriend()
         {
-            Assert.AreEqual(95, AstContext.FindFunction("operator+").First().LineNumberStart);
+            Assert.AreEqual(93, AstContext.FindFunction("operator+").First().LineNumberStart);
         }
 
         static string StripWindowsNewLines(string text)
@@ -350,7 +350,7 @@ namespace CppSharp.Generator.Tests.AST
         [Test]
         public void TestMacroLineNumber()
         {
-            Assert.AreEqual(105, AstContext.FindClass("HasAmbiguousFunctions").First().Specifiers.Last().LineNumberStart);
+            Assert.AreEqual(103, AstContext.FindClass("HasAmbiguousFunctions").First().Specifiers.Last().LineNumberStart);
         }
 
         [Test]
@@ -576,30 +576,5 @@ namespace CppSharp.Generator.Tests.AST
             var @classC = AstContext.FindClass("ClassC").First();
             Assert.That(@classC.Redeclarations.Count, Is.EqualTo(2));
         }
-
-        [Test]
-        public void TestRemovalOfUnusedStdTypes()
-        {
-            new IgnoreSystemDeclarationsPass { Context = Driver.Context }.VisitASTContext(AstContext);
-            if (Platform.IsWindows)
-            {
-                Assert.That(AstContext.GetEnumWithMatchingItem("_ALLOC_MASK").Ignore, Is.True);
-                Assert.That(AstContext.FindClass("_Ctypevec").First().Ignore, Is.True);
-                return;
-            }
-            if (Platform.IsLinux)
-            {
-                Assert.That(AstContext.GetEnumWithMatchingItem("PTHREAD_RWLOCK_PREFER_READER_NP").Ignore, Is.True);
-                Assert.That(AstContext.FindClass("pthread_mutex_t").First().Ignore, Is.True);
-                return;
-
-            }
-            if (Platform.IsMacOS)
-            {
-                Assert.That(AstContext.GetEnumWithMatchingItem("__n_words").Ignore, Is.True);
-                Assert.That(AstContext.FindClass("__darwin_fp_control").First().Ignore, Is.True);
-                return;
-            }
-        }
     }
 }
diff --git a/tests/Native/AST.h b/tests/Native/AST.h
index 8f4dea4b..41dc2db2 100644
--- a/tests/Native/AST.h
+++ b/tests/Native/AST.h
@@ -1,5 +1,3 @@
-#include <string>
-
 #define Q_SIGNALS protected
 
 // Tests assignment of AST.Parameter properties