GHC.TcPluginM.Extra

Create new constraints

newWanted :: CtLoc -> PredType -> TcPluginM CtEvidence

Create a new [W]anted constraint.

newGiven :: CtLoc -> PredType -> EvTerm -> TcPluginM CtEvidence

Create a new [G]iven constraint, with the supplied evidence. This must not be invoked from tcPluginInit or tcPluginStop, or it will panic.

newDerived :: CtLoc -> PredType -> TcPluginM CtEvidence

Create a new [D]erived constraint.

newWantedWithProvenance

Arguments

:: CtEvidence

Constraint from which the new wanted is derived

-> PredType

The type of the new constraint

-> TcPluginM CtEvidence

Create a new [W]anted constraint that remembers from which wanted constraint it was derived

Creating evidence

evByFiat

Arguments

:: String

Name the coercion should have

-> Type

The LHS of the equivalence relation (~)

-> Type

The RHS of the equivalence relation (~)

-> EvTerm

The EvTerm equivalent for unsafeCoerce

Report contractions

failWithProvenace :: Ct -> TcPluginM TcPluginResult

Mark the given constraint as insoluble.

If the [W]anted constraint was made by newWantedWithProvenance, it will also mark the parent(s) from which the constraint was derived as insoluble. Even if they were previously assumed to be solved.

Lookup

lookupModule

Arguments

:: ModuleName

Name of the module

-> FastString

Name of the package containing the module

-> TcPluginM Module

Find a module

lookupName :: Module -> OccName -> TcPluginM Name

Find a Name in a Module given an OccName

Trace state of the plugin

tracePlugin :: String -> TcPlugin -> TcPlugin

Print out extra information about the initialisation, stop, and every run of the plugin when -ddump-tc-trace is enabled.