diff --git a/libsolidity/Exceptions.h b/libsolidity/Exceptions.h
index 723475c7252b..5a1b827c7e3d 100644
--- a/libsolidity/Exceptions.h
+++ b/libsolidity/Exceptions.h
@@ -41,6 +41,7 @@ class Error: virtual public Exception
 		DocstringParsingError,
 		ParserError,
 		TypeError,
+
 		Warning
 	};
 
@@ -69,7 +70,7 @@ class Error: virtual public Exception
 		}
 	}
 
-	Type type() { return m_type; }
+	Type const type() { return m_type; } const
 	std::string const& typeName() const { return m_typeName; }
 
 private:
diff --git a/libsolidity/TypeChecker.cpp b/libsolidity/TypeChecker.cpp
index 658e48747e7c..e32644290ed1 100644
--- a/libsolidity/TypeChecker.cpp
+++ b/libsolidity/TypeChecker.cpp
@@ -45,11 +45,14 @@ bool TypeChecker::checkTypeRequirements(const ContractDefinition& _contract)
 	}
 	bool success = true;
 	for (auto const& it: m_errors)
-		if (!dynamic_cast<Warning const*>(it.get()))
+	{
+		Error const& e = dynamic_cast<Error const&>(it.get());
+		if (e.type() != Error::Type::Warning)
 		{
 			success = false;
 			break;
 		}
+	}
 	return success;
 }
 
diff --git a/libsolidity/TypeChecker.h b/libsolidity/TypeChecker.h
index cb65d5a8aa56..c654c698a31e 100644
--- a/libsolidity/TypeChecker.h
+++ b/libsolidity/TypeChecker.h
@@ -47,7 +47,7 @@ class TypeChecker: private ASTConstVisitor
 	bool checkTypeRequirements(ContractDefinition const& _contract);
 
 	/// @returns the list of errors and warnings found during type checking.
-	std::vector<std::shared_ptr<Error const>> const& errors() const { return m_errors; }
+	ErrorList const& errors() const { return m_errors; }
 
 	/// @returns the type of an expression and asserts that it is present.
 	TypePointer const& type(Expression const& _expression) const;
@@ -114,7 +114,7 @@ class TypeChecker: private ASTConstVisitor
 	/// Runs type checks on @a _expression to infer its type and then checks that it is an LValue.
 	void requireLValue(Expression const& _expression);
 
-	std::vector<std::shared_ptr<Error const>> m_errors;
+	ErrorList m_errors;
 };
 
 }