[PreetRajput]

#4058

Problem

Fixes the handling of optional and params parameters when decompiling lambda expressions, particularly when targeting C# language versions below C# 12.

Solution

• For C# 12 and later, the decompiler emits optional parameter defaults and params modifiers directly in lambda parameter lists.
• For earlier C# versions, it preserves optional parameter information using [Optional] and [DefaultParameterValue(value)] attributes instead of emitting unsupported default-value syntax.
• Unsupported params modifiers are omitted for earlier language versions to ensure the generated code remains valid.

Tests

• Ran the existing PrettyTestRunner.LambdaOptionalAndParamsParameters test.
• Result: 4 passed, 0 failed.