ucsd-progsys/liquidhaskell

Specs not exported from preprocessed source code

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#2,132 创建于 2023年1月1日

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good first issue

描述

Consider the following example, where the source for the A module is preprocessed with hsc2hs:

# A.hsc
module A where

{-@ type Foo = { v : Int | v = 5 } @-}

# B.hs
module B where

import A

{-@ foo :: Foo @-}
foo = 5

LH fails with the following error:

[1 of 2] Compiling A

**** LIQUID: SAFE (0 constraints checked) **************************************
[2 of 2] Compiling B
ghc: panic! (the 'impossible' happened)
  (GHC version 8.10.7:
	[src/B.hs:5:12-14 Unknown type constructor `Foo`
                     matchTyCon: Foo]

If A.hsc is renamed to A.hs instead, then everything works fine. This problem might be hsc2hs-specific, but I suspect it's a more general problem with preprocessed source code.

Version of LH used: 0.8.10.7 (latest release on Hackage at time of writing)

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领域
toolingbuild system
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
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clear
前置要求
Knowledge of HaskellFamiliarity with LiquidHaskellUnderstanding of hsc2hs preprocessing
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
35
研究方向
Investigate how LiquidHaskell processes preprocessed source files like .hsc. Look at the code in the liquidhaskell repository, particularly the modules handling GHC plugin operations and interface generation. The difference between .hsc and .hs suggests a parsing or file extension handling issue. Check if the preprocessing step affects the export of liquid type specifications. Start by examining the 'src/' directory for files that deal with source preprocessing and type export. Document findings in a comment on the issue and consider reaching out to maintainers for further guidance.