Add docs for GHC-78892 #429
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david-christiansen
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david-christiansen
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It's OK as is, but I suggested a minor tweak to the wording
| introduced: 9.6.1 | ||
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| Pattern matching allows constructors and literals to be used to take apart values, exposing their contents. The `let ... in ...` syntax is used to introduce declarations that are scoped to an expression. See [GHC-04584](https://errors.haskell.org/messages/GHC-78892/) for more information on why expressions aren't permitted in pattern matching. |
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| Pattern matching allows constructors and literals to be used to take apart values, exposing their contents. The `let ... in ...` syntax is used to introduce declarations that are scoped to an expression. See [GHC-04584](https://errors.haskell.org/messages/GHC-78892/) for more information on why expressions aren't permitted in pattern matching. | |
| Pattern matching allows constructors and literals to be used to take apart values, exposing their contents. Even though patterns resemble expressions, they are not evaluated. The `let ... in ...` syntax is used to introduce declarations that are scoped to an expression, which doesn't make sense as a pattern without evaluation. See [GHC-04584](https://errors.haskell.org/messages/GHC-78892/) for more information on why expressions aren't permitted in pattern matching. |
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Thanks! |
david-christiansen
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Jun 22, 2023
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Thank you again :-) |
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Closes #61