protected override void WalkNonNull(IAbstractSyntax syntax, BindingScope bindingScope)
{
switch (syntax)
{
case IConcreteInvocableDeclaration syn:
foreach (var parameter in syn.Parameters.OfType <INamedParameter>())
{
bindingScope = new VariableBindingScope(bindingScope, parameter);
}
break;
case IFieldDeclaration syn:
WalkChildren(syn, bindingScope);
break;
case IBodyOrBlock syn:
foreach (var statement in syn.Statements)
{
WalkNonNull(statement, bindingScope);
// Each variable declaration establishes a new binding scope
if (statement is IVariableDeclarationStatement variableDeclaration)
{
bindingScope = new VariableBindingScope(bindingScope, variableDeclaration);
}
}
return;
case IVariableDeclarationStatement syn:
{
WalkChildren(syn, bindingScope);
if (!bindingScope.Lookup(syn.Symbol.Name, out var binding))
{
return;
}
if (binding.MutableBinding)
{
diagnostics.Add(SemanticError.CantRebindMutableBinding(file, syn.NameSpan));
}
else if (syn.Symbol.IsMutableBinding)
{
diagnostics.Add(SemanticError.CantRebindAsMutableBinding(file, syn.NameSpan));
}
return;
}
case INameExpression syn:
{
// This checks for cases where a variable was shadowed, but then used later
if (!bindingScope.Lookup(syn.ReferencedSymbol.Name, out var binding))
{
return;
}
if (binding.WasShadowedBy.Any())
{
diagnostics.Add(SemanticError.CantShadow(file, binding.WasShadowedBy[^ 1].NameSpan, syn.Span));
public override void VisitIdentifierName(IdentifierNameSyntax identifierName, BindingScope bindingScope)
{
if (!bindingScope.Lookup(identifierName.Name, out var binding))
{
return;
}
var shadowedBy = binding.WasShadowedBy.LastOrDefault();
if (shadowedBy == null)
{
return;
}
diagnostics.Add(SemanticError.CantShadow(function.File, shadowedBy.NameSpan, identifierName.Span));
function.Poison();
}