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GHC 10.0.0.20260917 · lts/ghc-10.0.x · 8fef28d · 2026-11-02

Moduleghc-10.0.0.20260917GHC2024

GHC.Tc.Errors.Hole.Plugin

Synopsis

type CandPlugin
type FitPlugin
data HoleFitPlugin
data HoleFitPluginR

Packageghc-10.0.0.20260917
Exports4
LanguageGHC2024
LicenceBSD-3-Clause
SourcePlugin.hs

typetype CandPlugin = TypedHole -> [HoleFitCandidate] -> TcM [HoleFitCandidate]

A plugin for modifying the candidate hole fits *before* they're checked.

typetype FitPlugin = TypedHole -> [HoleFit] -> TcM [HoleFit]

A plugin for modifying hole fits *after* they've been found.

datadata HoleFitPlugin

A HoleFitPlugin is a pair of candidate and fit plugins.

Constructors

HoleFitPlugin
- candPlugin :: CandPlugin
- fitPlugin :: FitPlugin

datadata HoleFitPluginR

HoleFitPluginR adds a TcRef to hole fit plugins so that plugins can track internal state. Note the existential quantification, ensuring that the state cannot be modified from outside the plugin.

Constructors

forall s. HoleFitPluginR
- hfPluginInit :: TcM (TcRef s)
  Initializes the TcRef to be passed to the plugin
- hfPluginRun :: TcRef s -> HoleFitPlugin
  The function defining the plugin itself
- hfPluginStop :: TcRef s -> TcM ()
  Cleanup of state, guaranteed to be called even on error