Record copy constructor should leverage base copy constructor #44902
Description
[Fact]
public void TODO()
{
var src = @"
public record Human(int age) { }
public record Person(string First, string Last) : Human(0) { }
";
var comp = CreateCompilation(src);
comp.VerifyDiagnostics(
// (4,15): error CS1729: 'Human' does not contain a constructor that takes 0 arguments
// public record Person(string First, string Last) : Human(0)
Diagnostic(ErrorCode.ERR_BadCtorArgCount, "Person").WithArguments("Human", "0").WithLocation(4, 15)
);
}
In a scenario that compiles, the copy constructor for Person looks like this:
.method public hidebysig specialname rtspecialname
instance void .ctor (
class Person ''
) cil managed
{
// Method begins at RVA 0x214d
// Code size 32 (0x20)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call instance void Human::.ctor()
IL_0006: nop
IL_0007: ldarg.0
IL_0008: ldarg.1
IL_0009: ldfld string Person::'<First>k__BackingField'
IL_000e: stfld string Person::'<First>k__BackingField'
IL_0013: ldarg.0
IL_0014: ldarg.1
IL_0015: ldfld string Person::'<Last>k__BackingField'
IL_001a: stfld string Person::'<Last>k__BackingField'
IL_001f: ret
} // end of method Person::.ctor
Conclusions from offline group for copy constructors:
- don't include initializers
- require delegate to base copy constructor (user defined)
- delegate to base copy constructor, except for object (synthesized)
- error if not accessible during synthesis