[Mono.Android.Export] Enable nullable reference types and remove MONOTOUCH guard in CodeWhen.cs

[Copilot]

CodeWhen.cs ships in Mono.Android.Export.dll but was compiled in a nullable-oblivious context, getting no compile-time null-safety checks. The class is already null-correct, making it a low-risk opt-in candidate.

Changes

• Added #nullable enable to src/Mono.Android.Export/Mono.CodeGeneration/CodeWhen.cs.
• Removed the legacy #if !MONOTOUCH / #endif wrapper around the file so the nullable context is applied unconditionally.

#nullable enable

using System;

Directive/preprocessor-only change — no logic modifications. All three reference-type fields (condition, trueBlock, falseBlock) are unconditionally assigned in the single constructor, and methods dereference only non-null fields/parameters, so no nullable warnings are produced and no ! null-forgiving operator was needed.

[Copilot]

Pull request overview

Enables nullable reference types for CodeWhen.cs in Mono.Android.Export so the file participates in compile-time null-safety analysis without changing runtime behavior.

Changes:

• Added #nullable enable inside the existing #if !MONOTOUCH guard at the top of src/Mono.Android.Export/Mono.CodeGeneration/CodeWhen.cs.

[jonathanpeppers]

@copilot can we remove the stupid #if !MONOTOUCH as well?

[Copilot]

Done in d5a3641 — I removed the #if !MONOTOUCH / #endif wrapper from CodeWhen.cs and kept #nullable enable in place.