Require modifiers to contain "_".

Author: chriseth

libsolidity/analysis/SyntaxChecker.cpp

@@ -40,13 +40,26 @@ void SyntaxChecker::syntaxError(SourceLocation const& _location, std::string con
 	m_errors.push_back(err);
 }
 
+bool SyntaxChecker::visit(ModifierDefinition const&)
+{
+	m_placeholderFound = false;
+	return true;
+}
+
+void SyntaxChecker::endVisit(ModifierDefinition const& _modifier)
+{
+	if (!m_placeholderFound)
+		syntaxError(_modifier.body().location(), "Modifier body does not contain '_'.");
+	m_placeholderFound = false;
+}
+
 bool SyntaxChecker::visit(WhileStatement const&)
 {
 	m_inLoopDepth++;
 	return true;
 }
 
-void SyntaxChecker::endVisit(WhileStatement const&)
+void SyntaxChecker::endVisit(WhileStatement const&	)
 {
 	m_inLoopDepth--;
 }
@@ -78,3 +91,9 @@ bool SyntaxChecker::visit(Break const& _breakStatement)
 	return true;
 }
 
+bool SyntaxChecker::visit(const PlaceholderStatement&)
+{
+	m_placeholderFound = true;
+	return true;
+}
+

libsolidity/analysis/SyntaxChecker.h

@@ -31,6 +31,7 @@ namespace solidity
 /**
  * The module that performs syntax analysis on the AST:
  *  - whether continue/break is in a for/while loop.
+ *  - whether a modifier contains at least one '_'
  */
 class SyntaxChecker: private ASTConstVisitor
 {
@@ -44,6 +45,9 @@ class SyntaxChecker: private ASTConstVisitor
 	/// Adds a new error to the list of errors.
 	void syntaxError(SourceLocation const& _location, std::string const& _description);
 
+	virtual bool visit(ModifierDefinition const& _modifier) override;
+	virtual void endVisit(ModifierDefinition const& _modifier) override;
+
 	virtual bool visit(WhileStatement const& _whileStatement) override;
 	virtual void endVisit(WhileStatement const& _whileStatement) override;
 	virtual bool visit(ForStatement const& _forStatement) override;
@@ -52,8 +56,13 @@ class SyntaxChecker: private ASTConstVisitor
 	virtual bool visit(Continue const& _continueStatement) override;
 	virtual bool visit(Break const& _breakStatement) override;
 
+	virtual bool visit(PlaceholderStatement const& _placeholderStatement) override;
+
 	ErrorList& m_errors;
 
+	/// Flag that indicates whether a function modifier actually contains '_'.
+	bool m_placeholderFound = false;
+
 	int m_inLoopDepth = 0;
 };
 

test/libsolidity/SolidityNameAndTypeResolution.cpp

@@ -3823,6 +3823,16 @@ BOOST_AUTO_TEST_CASE(unused_return_value_delegatecall)
 	BOOST_CHECK(expectError(text, true) == Error::Type::Warning);
 }
 
+BOOST_AUTO_TEST_CASE(modifier_without_underscore)
+{
+	char const* text = R"(
+		contract test {
+			modifier m() {}
+		}
+	)";
+	BOOST_CHECK(expectError(text, true) == Error::Type::SyntaxError);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }