dotnet/roslyn

VB compiler should not "optimize" Select statements during initial binding

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#374 建立於 2015年2月10日

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 (3 留言) (0 反應) (0 負責人)C# (20,414 star) (4,257 fork)batch import
Area-CompilersBugConcept-Design DebtLanguage-VBhelp wanted

描述

The VB compiler "optimizes" Select statements during initial binding, generating and storing a lowered form for the cases depending on the structure of the whole select statement.

Generally speaking such transformations belong in lowering. Since it operates at the level of the whole Select statement after all of the parts have been bound, it can be moved en masse to a later phase. I recommend the local lowering phase.

Any intermediate phases that depend on the lowering having taken place are likely buggy, since different lowered forms may be generated in different circumstances.

[ported from TFS DevDiv 941313]

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技術棧
csharp
領域
toolingperformance
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
4
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
3-5 days
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
compiler internalsRoslyn architectureVB.NET syntaxlowering phases
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
25
研究方向
Examine the VB compiler's initial binding phase to locate the premature optimization of Select statements. The issue recommends moving this transformation to the local lowering phase. Review the lowering pass structure in the Roslyn repository, likely in the 'Features/VisualBasic' or 'Compilers/VisualBasic' directories. Check linked TFS issue for more context.