Fix import directive visits in type checker and view pure checker.

libsolidity/analysis/TypeChecker.cpp

@@ -268,6 +268,11 @@ TypePointers TypeChecker::typeCheckMetaTypeFunctionAndRetrieveReturnType(Functio
 	return {TypeProvider::meta(dynamic_cast<TypeType const&>(*firstArgType).actualType())};
 }
 
+bool TypeChecker::visit(ImportDirective const&)
+{
+	return false;
+}
+
 void TypeChecker::endVisit(InheritanceSpecifier const& _inheritance)
 {
 	auto base = dynamic_cast<ContractDefinition const*>(&dereference(_inheritance.name()));

libsolidity/analysis/TypeChecker.h

@@ -125,6 +125,8 @@ private:
 		FunctionType const* _functionType
 	);
 
+	bool visit(ImportDirective const&) override;
+
 	void endVisit(InheritanceSpecifier const& _inheritance) override;
 	void endVisit(ModifierDefinition const& _modifier) override;
 	bool visit(FunctionDefinition const& _function) override;

libsolidity/analysis/ViewPureChecker.cpp

@@ -134,6 +134,11 @@ bool ViewPureChecker::check()
 	return !m_errors;
 }
 
+bool ViewPureChecker::visit(ImportDirective const&)
+{
+	return false;
+}
+
 bool ViewPureChecker::visit(FunctionDefinition const& _funDef)
 {
 	solAssert(!m_currentFunction, "");

libsolidity/analysis/ViewPureChecker.h

@@ -50,6 +50,8 @@ private:
 		langutil::SourceLocation location;
 	};
 
+	bool visit(ImportDirective const&) override;
+
 	bool visit(FunctionDefinition const& _funDef) override;
 	void endVisit(FunctionDefinition const& _funDef) override;
 	bool visit(ModifierDefinition const& _modifierDef) override;