Support parsing let statements without a value

libsolidity/inlineasm/AsmAnalysis.cpp

@@ -174,14 +174,20 @@ bool AsmAnalyzer::operator()(assembly::Assignment const& _assignment)
 
 bool AsmAnalyzer::operator()(assembly::VariableDeclaration const& _varDecl)
 {
+	bool success = true;
 	int const expectedItems = _varDecl.variables.size();
-	int const stackHeight = m_stackHeight;
-	bool success = boost::apply_visitor(*this, *_varDecl.value);
-	if ((m_stackHeight - stackHeight) != expectedItems)
+	if (_varDecl.value)
 	{
-		m_errorReporter.declarationError(_varDecl.location, "Variable count mismatch.");
-		return false;
+		int const stackHeight = m_stackHeight;
+		success = boost::apply_visitor(*this, *_varDecl.value);
+		if ((m_stackHeight - stackHeight) != expectedItems)
+		{
+			m_errorReporter.declarationError(_varDecl.location, "Variable count mismatch.");
+			return false;
+		}
 	}
+	else
+		m_stackHeight += expectedItems;
 
 	for (auto const& variable: _varDecl.variables)
 	{

libsolidity/inlineasm/AsmParser.cpp

@@ -347,10 +347,15 @@ assembly::VariableDeclaration Parser::parseVariableDeclaration()
 		else
 			break;
 	}
-	expectToken(Token::Colon);
-	expectToken(Token::Assign);
-	varDecl.value.reset(new Statement(parseExpression()));
-	varDecl.location.end = locationOf(*varDecl.value).end;
+	if (currentToken() == Token::Colon)
+	{
+		expectToken(Token::Colon);
+		expectToken(Token::Assign);
+		varDecl.value.reset(new Statement(parseExpression()));
+		varDecl.location.end = locationOf(*varDecl.value).end;
+	}
+	else
+		varDecl.location.end = varDecl.variables.back().location.end;
 	return varDecl;
 }
 

libsolidity/inlineasm/AsmPrinter.cpp

@@ -128,8 +128,11 @@ string AsmPrinter::operator()(assembly::VariableDeclaration const& _variableDecl
 		),
 		", "
 	);
-	out += " := ";
-	out += boost::apply_visitor(*this, *_variableDeclaration.value);
+	if (_variableDeclaration.value)
+	{
+		out += " := ";
+		out += boost::apply_visitor(*this, *_variableDeclaration.value);
+	}
 	return out;
 }