Merge pull request #1506 from federicobond/improve-error-msg

Improve error message when trying to modify constant variables
This commit is contained in:
chriseth 2016-12-13 15:27:02 +01:00 committed by GitHub
commit 9d60734549
3 changed files with 19 additions and 1 deletions

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@ -1529,6 +1529,8 @@ bool TypeChecker::visit(Identifier const& _identifier)
!!annotation.referencedDeclaration,
"Referenced declaration is null after overload resolution."
);
auto variableDeclaration = dynamic_cast<VariableDeclaration const*>(annotation.referencedDeclaration);
annotation.isConstant = variableDeclaration != nullptr && variableDeclaration->isConstant();
annotation.isLValue = annotation.referencedDeclaration->isLValue();
annotation.type = annotation.referencedDeclaration->type();
if (!annotation.type)
@ -1612,7 +1614,10 @@ void TypeChecker::requireLValue(Expression const& _expression)
{
_expression.annotation().lValueRequested = true;
_expression.accept(*this);
if (!_expression.annotation().isLValue)
if (_expression.annotation().isConstant)
typeError(_expression.location(), "Cannot assign to a constant variable.");
else if (!_expression.annotation().isLValue)
typeError(_expression.location(), "Expression has to be an lvalue.");
}

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@ -154,6 +154,8 @@ struct ExpressionAnnotation: ASTAnnotation
{
/// Inferred type of the expression.
TypePointer type;
/// Whether the expression is a constant variable
bool isConstant = false;
/// Whether it is an LValue (i.e. something that can be assigned to).
bool isLValue = false;
/// Whether the expression is used in a context where the LValue is actually required.

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@ -4865,6 +4865,17 @@ BOOST_AUTO_TEST_CASE(does_not_warn_msg_value_in_modifier_following_non_payable_p
CHECK_SUCCESS_NO_WARNINGS(text);
}
BOOST_AUTO_TEST_CASE(assignment_to_constant)
{
char const* text = R"(
contract c {
uint constant a = 1;
function f() { a = 2; }
}
)";
CHECK_ERROR(text, TypeError, "Cannot assign to a constant variable.");
}
BOOST_AUTO_TEST_SUITE_END()
}