Introduce `hsExprType :: HsExpr GhcTc -> Type` in the new modulewip/hsExprType

`GHC.Hs.Syn.Type`

The existing `hsPatType`, `hsLPatType` and `hsLitType` functions have also been
moved to this module

This is a less ambitious take on the same problem that !2182 and !3866
attempt to solve. Rather than have the `hsExprType` function attempt to
efficiently compute the `Type` of every subexpression in an `HsExpr`, this
simply computes the overall `Type` of a single `HsExpr`.

- Explicitly forbids the `SplicePat` `HsIPVar`, `HsBracket`, `HsRnBracketOut`
  and `HsTcBracketOut` constructors during the typechecking phase by using
  `Void` as the TTG extension field
- Also introduces `dataConCantHappen` as a domain specific alternative to `absurd`
  to handle cases where the TTG extension points forbid a constructor.
- Turns HIE file generation into a pure function that doesn't need access to the
  `DsM` monad to compute types, but uses `hsExprType` instead.
- Computes a few more types during HIE file generation
- Makes GHCi's `:set +c` command also use `hsExprType` instead of going through
  the desugarer to compute types.

Updates haddock submodule

Co-authored-by: Zubin Duggal <zubin.duggal@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/compiler/ghc.cabal.in b/compiler/ghc.cabal.in
index a1a1d967cd..b896cbbfb8 100644
--- a/compiler/ghc.cabal.in
+++ b/compiler/ghc.cabal.in
@@ -414,6 +414,7 @@ Library
         GHC.Hs.Doc
         GHC.Hs.Dump
         GHC.Hs.Expr
+        GHC.Hs.Syn.Type
         GHC.Hs.Extension
         GHC.Hs.ImpExp
         GHC.Hs.Instances