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Alex generates code with unqualified imports, e.g. of GHC.Exts #258

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andreasabel opened this issue Feb 27, 2024 · 0 comments · Fixed by #259
Closed

Alex generates code with unqualified imports, e.g. of GHC.Exts #258

andreasabel opened this issue Feb 27, 2024 · 0 comments · Fixed by #259
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bug
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3.5.1.0

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@andreasabel
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jukebox-0.5.4 broke with GHC 9.4 because a new export Symbol form GHC.Exts clashes with a user-defined identifier of the same name. This is pretty bad, as it is inconvenient for the user to work around this.

Unqualified imports in generated code are just a ticking time bomb. It makes packages using Alex brittle. (And there is no material need for unqualified imports.)

The way forward here is to change Alex so that all its identifiers it imports are used qualified, so that there is no risk of clashing with user-defined identifiers.

See a parallel effort in BNFC:
@andreasabel andreasabel mentioned this issue Feb 27, 2024
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andreasabel added a commit that referenced this issue Feb 27, 2024
@andreasabel
Test for #258: provoke clash with GHC.Exts.Symbol
e880446
andreasabel added a commit that referenced this issue Feb 27, 2024
@andreasabel
Test for #258: provoke clash with GHC.Exts.Symbol
a335798
@andreasabel andreasabel added this to the 3.5.1.0 milestone Feb 27, 2024
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this issue Apr 12, 2024
@0-wiz-0
alex: update to 3.5.1.0.
9df635a 
## Changes in 3.5.1.0

* Drop generating output for GHC < 6.4.
* Use qualified imports in generated code (except for `Prelude`)
  ([Issue #258](haskell/alex#258)).
* Suppress warnings `tabs` and `unused-imports` for generated code
  ([Issue #255](haskell/alex#255)).
* Tested with GHC 8.0 - 9.8.2.

## Changes in 3.5.0.0

 * Add option `--numeric-version`.
 * Remove deprecated `-v` as alias for `--version`.
 * Add `-v` as placeholder for a future `--verbose` option.
 * Make `alex{G,S}etUserState` available with the `monadUserState-bytestring` wrapper
   ([Issue #220](haskell/alex#220)).
 * Debugging lexer: print character in addition to its ASCII code
   ([PR #252](haskell/alex#252)).
 * Tested with GHC 8.0 - 9.8.1.
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Generate _qualified_ imports to avoid clashes with user code haskell/alex
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@andreasabel