Two snippets below fails with NRE
- Equality
type Bar = { b: obj }
type Foo = { f: Bar | null }
let a = { f = null }
let b = { f = null }
a = bError
System.NullReferenceException: Object reference not set to an instance of an object.
at FSI_0045.Foo.Equals(Foo obj, IEqualityComparer comp)
at <StartupCode$FSI_0048>.$FSI_0048.main@()
at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)
Stopped due to error
- Hash code
type Bar = { b: obj }
type Foo = { f: Bar | null }
let a = { f = null }
a.GetHashCode()Error
System.NullReferenceException: Object reference not set to an instance of an object.
at FSI_0017.Foo.GetHashCode(IEqualityComparer comp)
at FSI_0017.Foo.GetHashCode()
at <StartupCode$FSI_0019>.$FSI_0019.main@()
at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)
Stopped due to error
Known workarounds
change Bar to be NON record
type Bar = class end
type Foo = { f: Bar | null }
let a = { f = null }
let b = { f = null }
a = b // works nowRelated information
- Windows 10
- Microsoft (R) F# Interactive version 12.9.101.0 for F# 9.0
dotnet --list-sdks
5.0.408 [C:\Program Files\dotnet\sdk]
6.0.203 [C:\Program Files\dotnet\sdk]
6.0.321 [C:\Program Files\dotnet\sdk]
6.0.428 [C:\Program Files\dotnet\sdk]
7.0.120 [C:\Program Files\dotnet\sdk]
7.0.203 [C:\Program Files\dotnet\sdk]
7.0.317 [C:\Program Files\dotnet\sdk]
7.0.410 [C:\Program Files\dotnet\sdk]
8.0.112 [C:\Program Files\dotnet\sdk]
8.0.308 [C:\Program Files\dotnet\sdk]
8.0.405 [C:\Program Files\dotnet\sdk]
9.0.102 [C:\Program Files\dotnet\sdk]
Two snippets below fails with NRE
Error
Error
Known workarounds
change Bar to be NON record
Related information