diff --git a/AST.h b/AST.h
old mode 100644
new mode 100755
diff --git a/CompilerContext.cpp b/CompilerContext.cpp
index 18357bf0c..5d10a5f95 100644
--- a/CompilerContext.cpp
+++ b/CompilerContext.cpp
@@ -53,8 +53,8 @@ void CompilerContext::addAndInitializeVariable(VariableDeclaration const& _decla
 {
 	addVariable(_declaration);
 
-	unsigned const size = _declaration.getType()->getSizeOnStack();
-	for (unsigned i = 0; i < size; ++i)
+	int const size = _declaration.getType()->getSizeOnStack();
+	for (int i = 0; i < size; ++i)
 		*this << u256(0);
 	m_asm.adjustDeposit(-size);
 }
diff --git a/CompilerContext.h b/CompilerContext.h
index 795f447ab..14672c956 100644
--- a/CompilerContext.h
+++ b/CompilerContext.h
@@ -51,10 +51,10 @@ public:
 
 	void adjustStackOffset(int _adjustment) { m_asm.adjustDeposit(_adjustment); }
 
-	bool isMagicGlobal(Declaration const* _declaration) const { return m_magicGlobals.count(_declaration); }
-	bool isFunctionDefinition(Declaration const* _declaration) const { return m_functionEntryLabels.count(_declaration); }
+	bool isMagicGlobal(Declaration const* _declaration) const { return m_magicGlobals.count(_declaration) != 0; }
+	bool isFunctionDefinition(Declaration const* _declaration) const { return m_functionEntryLabels.count(_declaration) != 0; }
 	bool isLocalVariable(Declaration const* _declaration) const;
-	bool isStateVariable(Declaration const* _declaration) const { return m_stateVariables.count(_declaration); }
+	bool isStateVariable(Declaration const* _declaration) const { return m_stateVariables.count(_declaration) != 0; }
 
 	eth::AssemblyItem getFunctionEntryLabel(FunctionDefinition const& _function) const;
 	/// Returns the distance of the given local variable from the top of the local variable stack.
diff --git a/CompilerStack.cpp b/CompilerStack.cpp
index 174f9cd22..904c77c5a 100644
--- a/CompilerStack.cpp
+++ b/CompilerStack.cpp
@@ -39,7 +39,7 @@ namespace solidity
 
 bool CompilerStack::addSource(string const& _name, string const& _content)
 {
-	bool existed = m_sources.count(_name);
+	bool existed = m_sources.count(_name) != 0;
 	reset(true);
 	m_sources[_name].scanner = make_shared<Scanner>(CharStream(_content), _name);
 	return existed;
diff --git a/Types.h b/Types.h
index deabe1160..1ccdd706a 100644
--- a/Types.h
+++ b/Types.h
@@ -178,7 +178,7 @@ public:
 	int getNumBits() const { return m_bits; }
 	bool isHash() const { return m_modifier == Modifier::HASH || m_modifier == Modifier::ADDRESS; }
 	bool isAddress() const { return m_modifier == Modifier::ADDRESS; }
-	int isSigned() const { return m_modifier == Modifier::SIGNED; }
+	bool isSigned() const { return m_modifier == Modifier::SIGNED; }
 
 	static const MemberList AddressMemberList;
 
diff --git a/Utils.h b/Utils.h
old mode 100644
new mode 100755
index 8d6a3ab08..1411f66b4
--- a/Utils.h
+++ b/Utils.h
@@ -45,5 +45,11 @@ inline void solAssertAux(bool _condition, std::string const& _errorDescription,
 				<< ::boost::throw_line(_line));
 }
 
+inline void solAssertAux(void const* _pointer, std::string const& _errorDescription, unsigned _line,
+						 char const* _file, char const* _function)
+{
+	solAssertAux(_pointer != nullptr, _errorDescription, _line, _file, _function);
+}
+
 }
 }