public void VisitVariableDefinition(VariableDefinition variableDefinition)
{
if (variableDefinition.TypeSignature != null && variableDefinition.Initializer != null)
{
var variableType = TypeSignatureParser.ParseTypeSignature(
_context,
variableDefinition.TypeSignature);
if (!ExpressionAnalyzer.IsExpressionValid(
_context,
_currentScope,
variableDefinition.Initializer))
{
return;
}
var initializerType = Typer.GetExpressionType(
_context,
_currentScope,
variableDefinition.Initializer);
if (variableType != null && !variableType.IsSame(initializerType))
{
// We made sure in the StatementParser that a definition without both initializer
// and type signature is not a valid AST item and discarded it with an error.
Debug.Assert(variableDefinition.Initializer != null);
_context.Error(
variableDefinition.Initializer.Span,
$"expected type \"{variableType}\", but found \"{initializerType}\"");
}
_astContext.AddNodeType(variableDefinition.NodeId, variableType);
}
else if (variableDefinition.TypeSignature != null &&
variableDefinition.Initializer == null)
{
var variableType =
TypeSignatureParser.ParseTypeSignature(
_context,
variableDefinition.TypeSignature);
_astContext.AddNodeType(variableDefinition.NodeId, variableType);
}
else // variableDefinition.TypeSignature == null && variableDefinition.Initializer != null
{
if (!ExpressionAnalyzer.IsExpressionValid(
_context,
_currentScope,
variableDefinition.Initializer))
{
return;
}
var initializerType = Typer.GetExpressionType(
_context,
_currentScope,
variableDefinition.Initializer);
switch (initializerType)
{
case VoidType _:
// Again, the linter is overly sensitive. There's no way for the Initializer
// field to be null at this point.
Debug.Assert(variableDefinition.Initializer != null);
_context.Error(
variableDefinition.Initializer.Span,
"type \"void\" cannot be assigned to a variable");
break;
case null:
return;
default:
_astContext.AddNodeType(variableDefinition.NodeId, initializerType);
break;
}
}
if (!_currentScope.DefineSymbol(
variableDefinition,
_astContext.GetNodeType(variableDefinition.NodeId)))
{
_context.Error(
variableDefinition.Span,
$"redefined previously defined symbol \"{variableDefinition.Identifier}\"");
}
}
public static IType ParseTypeSignature(Context context, ITypeSignature typeSignature)
{
var self = new TypeSignatureParser(context);
return(typeSignature.Accept(self));
}
