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[[_TOC_]]
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# GHC 8.2.x Migration Guide
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... | ... | @@ -173,7 +175,7 @@ instance C (Proxy a) where |
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This compiles in GHC 8.0, but in GHC 8.2, it gives this error:
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```wiki
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```
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• Couldn't match type ‘k0’ with ‘k1’
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because type variable ‘k1’ would escape its scope
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This (rigid, skolem) type variable is bound by
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... | ... | @@ -214,7 +216,7 @@ instance C (Proxy a) where |
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In order to future-proof your packages for upcoming changes, add the following snippet to your `.cabal` file, and address the warnings emitted by GHC when compiling your package:
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```wiki
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```
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if impl(ghc >= 8.0)
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ghc-options: -Wcompat -Wnoncanonical-monad-instances -Wnoncanonical-monadfail-instances
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else
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... | ... | |