/// <summary>
/// Returns the expected argument type for a particular argument position, using function overload information.
/// </summary>
/// <param name="functionSymbol">The function symbol to inspect</param>
/// <param name="argIndex">The index of the function argument</param>
public static TypeSymbol GetDeclaredArgumentType(this FunctionSymbol functionSymbol, int argIndex)
{
// if we have a mix of wildcard and non-wildcard overloads, prioritize the non-wildcard overloads.
// the wildcards have super generic type definitions, so don't result in helpful completions.
var overloads = functionSymbol.Overloads.Any(x => x is not FunctionWildcardOverload) ?
functionSymbol.Overloads.Where(x => x is not FunctionWildcardOverload) :
functionSymbol.Overloads;
var argTypes = overloads
.Where(x => x.MaximumArgumentCount is null || argIndex < x.MaximumArgumentCount)
.Select(x => argIndex < x.FixedParameters.Length ? x.FixedParameters[argIndex].Type : (x.VariableParameter?.Type ?? LanguageConstants.Never));
return(TypeHelper.CreateTypeUnion(argTypes));
}
public virtual void VisitFunctionSymbol(FunctionSymbol symbol)
{
VisitDescendants(symbol);
}
public override void VisitFunctionSymbol(FunctionSymbol symbol)
{
base.VisitFunctionSymbol(symbol);
this.CollectDiagnostics(symbol);
}
