Closed
Description
Description
When binding to a type with a constructor that has a default string parameter, the generator emits code that doesn't compile.
C:\scratch\configStringCtorParam\Microsoft.Extensions.Configuration.Binder.SourceGeneration\Microsoft.Extensions.Config
uration.Binder.SourceGeneration.ConfigurationBindingGenerator\BindingExtensions.g.cs(77,27): error CS0103: The name 's'
does not exist in the current context [C:\scratch\configStringCtorParam\configStringCtorParam.csproj]
The code generated looks like this:
public static SD InitializeSD(IConfiguration configuration, BinderOptions? binderOptions)
{
if (configuration["S"] is string value1)
{
string s = value1;
}
return new SD(s);
}Bug is likely in the EmitBindImplForMember method but I haven't tracked it down. I suspect there's a disagreement between the case where the member is string parseable but also has a default value. This same repro works when removing the default value.
Reproduction Steps
using Microsoft.Extensions.Configuration;
var c = new ConfigurationBuilder().Build();
var x = c.Get<SD>();
Console.WriteLine(x);
public class SD
{
public SD(string s = "default value") { S = s; }
public string S { get;}
public override string ToString() => S;
}Expected behavior
Compiles successfully.
Actual behavior
Compilation failure.
Regression?
No
Known Workarounds
Remove default value from ctor param.
Configuration
No response
Other information
No response