Use ArrayExpansion for [InlineArray] structs#81254
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resolved comments @tmat |
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LGTM. @dotnet/roslyn-compiler should also sign off.
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Done with review pass (commit 2) #Closed |
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Thanks @asundheimMSFT! |
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# Overview [Fixed buffer fields](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/unsafe-code#fixed-size-buffers) look like structs with a single member in metadata, so we would use `MemberExpansion` which only shows the first element. Instead we should use `ArrayExpansion`, in a similar fashion to what we did for `[InlineArray]` in #81254. # Details - Added additional helper to `InlineArrayHelpers` that identifies generated fixed buffer types - Fixed up test mocks to handle some novel usage of certain LMR `Type` properties. # Testing Added test that validates that we get an `ArrayExpansion` for a fixed buffer. Comment in the test describes why we cannot use the typical testing approach that we use for other `ArrayExpansion` tests. <img width="784" height="156" alt="image" src="https://github.com/user-attachments/assets/8008bd22-9194-445a-b1d3-1b7a57de0a6b" />
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Overview
Currently inline array structs use the default
MemberExpansion, which only shows the first element / the single field:Details
[InlineArray]attributes and decode the Length and element typeArrayExpansionfor inline arraysTesting
The real complexity of this change came when trying to write a test that exercised this case. Since all the ResultProvider expansion tests rely on instantiating objects into the test host, then decoding them via reflection in the debugger engine mocks, some additional work was necessary to support the Net8+ inline array type.
$(NetRoslyn)target toResultProvider.UnitTestsandResultProvider.Utilities$(NetRoslyn)DkmClrValueto handleGetArrayElementfor inline arrays (ish, see comments about reflection and inline arrays)Fixes: #68983