Merge pull request #3142 from Balajiganapathi/allow_constant_array_length

Allow constant integer variables as array lengths.

2 files changed, 28 insertions, 2 deletions

diff --git a/libsolidity/analysis/ConstantEvaluator.cpp b/libsolidity/analysis/ConstantEvaluator.cpp
index bc3b7cf1..4d546e68 100644
--- a/libsolidity/analysis/ConstantEvaluator.cpp
+++ b/libsolidity/analysis/ConstantEvaluator.cpp
@@ -74,3 +74,25 @@ void ConstantEvaluator::endVisit(Literal const& _literal)
 	if (!_literal.annotation().type)
 		m_errorReporter.fatalTypeError(_literal.location(), "Invalid literal value.");
 }
+
+void ConstantEvaluator::endVisit(Identifier const& _identifier)
+{
+	VariableDeclaration const* variableDeclaration = dynamic_cast<VariableDeclaration const*>(_identifier.annotation().referencedDeclaration);
+	if (!variableDeclaration)
+		return;
+	if (!variableDeclaration->isConstant())
+		m_errorReporter.fatalTypeError(_identifier.location(), "Identifier must be declared constant.");
+
+	ASTPointer<Expression> value = variableDeclaration->value();
+	if (!value)
+		m_errorReporter.fatalTypeError(_identifier.location(), "Constant identifier declaration must have a constant value.");
+
+	if (!value->annotation().type)
+	{
+		if (m_depth > 32)
+			m_errorReporter.fatalTypeError(_identifier.location(), "Cyclic constant definition (or maximum recursion depth exhausted).");
+		ConstantEvaluator e(*value, m_errorReporter, m_depth + 1);
+	}
+
+	_identifier.annotation().type = value->annotation().type;
+}
diff --git a/libsolidity/analysis/ConstantEvaluator.h b/libsolidity/analysis/ConstantEvaluator.h
index 90bceb5d..6725d610 100644
--- a/libsolidity/analysis/ConstantEvaluator.h
+++ b/libsolidity/analysis/ConstantEvaluator.h
@@ -38,8 +38,9 @@ class TypeChecker;
 class ConstantEvaluator: private ASTConstVisitor
 {
 public:
-	ConstantEvaluator(Expression const& _expr, ErrorReporter& _errorReporter):
-		m_errorReporter(_errorReporter)
+	ConstantEvaluator(Expression const& _expr, ErrorReporter& _errorReporter, size_t _newDepth = 0):
+		m_errorReporter(_errorReporter),
+		m_depth(_newDepth)
 	{
 		_expr.accept(*this);
 	}
@@ -48,8 +49,11 @@ private:
 	virtual void endVisit(BinaryOperation const& _operation);
 	virtual void endVisit(UnaryOperation const& _operation);
 	virtual void endVisit(Literal const& _literal);
+	virtual void endVisit(Identifier const& _identifier);
 
 	ErrorReporter& m_errorReporter;
+	/// Current recursion depth.
+	size_t m_depth;
 };
 
 }