Warn about unused dependencies
GHC loads packages lazily, so at the end of compilation (at least in --make
mode) it knows all the dependencies, required to compile the code. See eps_PIT
in ExternalPackageState
. If we compare this list with the list of packages, passed on command like via --package-id
, then we'll get a list of unused dependencies.
I propose to add a flag -Wunused-packages
, off by default, which will report the unused packages if any.
Trac metadata
Trac field | Value |
---|---|
Version | 8.6.1 |
Type | FeatureRequest |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
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Blocking | |
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Operating system | |
Architecture |