+tcId :: Name -> TcM (TcExpr, TcType)
+tcId name -- Look up the Id and instantiate its type
+ = -- First check whether it's a DataCon
+ -- Reason: we must not forget to chuck in the
+ -- constraints from their "silly context"
+ tcLookupGlobal_maybe name `thenM` \ maybe_thing ->
+ case maybe_thing of {
+ Just (ADataCon data_con) -> inst_data_con data_con ;
+ other ->
+
+ -- OK, so now look for ordinary Ids
+ tcLookupIdLvl name `thenM` \ (id, bind_lvl) ->
+
+#ifndef GHCI
+ loop (HsVar id) (idType id) -- Non-TH case
+
+#else /* GHCI is on */
+ -- Check for cross-stage lifting
+ getStage `thenM` \ use_stage ->
+ case use_stage of
+ Brack use_lvl ps_var lie_var
+ | use_lvl > bind_lvl && not (isExternalName name)
+ -> -- E.g. \x -> [| h x |]
+ -- We must behave as if the reference to x was
+ -- h $(lift x)
+ -- We use 'x' itself as the splice proxy, used by
+ -- the desugarer to stitch it all back together.
+ -- If 'x' occurs many times we may get many identical
+ -- bindings of the same splice proxy, but that doesn't
+ -- matter, although it's a mite untidy.
+ --
+ -- NB: During type-checking, isExernalName is true of
+ -- top level things, and false of nested bindings
+ -- Top-level things don't need lifting.
+
+ let
+ id_ty = idType id
+ in
+ checkTc (isTauTy id_ty) (polySpliceErr id) `thenM_`
+ -- If x is polymorphic, its occurrence sites might
+ -- have different instantiations, so we can't use plain
+ -- 'x' as the splice proxy name. I don't know how to
+ -- solve this, and it's probably unimportant, so I'm
+ -- just going to flag an error for now
+
+ setLIEVar lie_var (
+ newMethodFromName orig id_ty DsMeta.liftName `thenM` \ lift ->
+ -- Put the 'lift' constraint into the right LIE
+
+ -- Update the pending splices
+ readMutVar ps_var `thenM` \ ps ->
+ writeMutVar ps_var ((name, HsApp (HsVar lift) (HsVar id)) : ps) `thenM_`
+
+ returnM (HsVar id, id_ty))