Optional ParameterInfo is lost at runtime for local functions #51518
Description
Version Used:
master (24 Feb 2021) on sharplab.io
Steps to Reproduce:
View this sharplab.io snippet and observe that this:
using System;
public class C {
public void M() {
void TestLocalAction(int a = 2)
{
}
MapAction((Action<int>)TestMethodAction);
MapAction((Action<int>)TestLocalAction);
}
public void TestMethodAction(int a = 2)
{
}
public void MapAction(Delegate action)
{
}
}results in this:
// ...
public class C
{
public void M()
{
MapAction(new Action<int>(TestMethodAction));
MapAction(new Action<int>(<M>g__TestLocalAction|0_0));
}
public void TestMethodAction(int a = 2)
{
}
public void MapAction(Delegate action)
{
}
[CompilerGenerated]
internal static void <M>g__TestLocalAction|0_0(int a)
{
}
}And that <M>g__TestLocalAction|0_0 does not have a default value unlike TestMethodAction.
Expected Behavior:
<M>g__TestLocalAction|0_0 should have int a = 2 in its parameter list.
Actual Behavior:
<M>g__TestLocalAction|0_0 does not have int a = 2 in its parameter lists. This becomes a problem for MapAction if it wants to call TestLocalAction with the default parameter value. Delegate.Method.GetParameters()[0].HasDefaultValue ends up returning false instead of true.
Thanks @Kahbazi for finding this! https://github.com/dotnet/aspnetcore/pull/30434/files#r583502436