Commit 960223bf authored by simonpj's avatar simonpj
Browse files

[project @ 1999-06-28 16:23:28 by simonpj]

Fix lost specialisations.  There were two problems

	{-# SPECIALISE f :: Int -> Rational #-}
	fromIntegral	=  fromInteger . toInteger

This generates

	fromIntegral_spec = fromIntegral d

for some suitable dictionary d.  But since fromIntegral is small,
it got inlined into fromIntegral_spec, thus losing the specialised
call (fromIntegral d) that was the whole raison d'etre of fromIntegral_spec.
Haskish solution: add an inlne pragma for the _spec things:

	fromIntegral_spec = _inline_me (fromIntegral d)

Now we won't inline inside.  But this showed up a related problem.  The
typechecker tries to common up overloaded things, so it actually generates

	m = fromIntegral d
	fromIntegral_spec = _inline_me m

which is pretty stupid.  Using tcSimplifyToDicts (instead of tcSimplify)
in TcBinds.tcSpecSigs fixes this.
parent 9956bafe
......@@ -16,7 +16,7 @@ import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..), InPat(..), Stmt
collectMonoBinders, andMonoBindList, andMonoBinds
)
import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds )
import TcHsSyn ( TcHsBinds, TcMonoBinds, TcId, zonkId )
import TcHsSyn ( TcHsBinds, TcMonoBinds, TcId, zonkId, mkHsLet )
import TcMonad
import Inst ( Inst, LIE, emptyLIE, mkLIE, plusLIE, plusLIEs, InstOrigin(..),
......@@ -27,7 +27,7 @@ import TcEnv ( tcExtendLocalValEnv,
tcLookupTyCon,
tcGetGlobalTyVars, tcExtendGlobalTyVars
)
import TcSimplify ( tcSimplify, tcSimplifyAndCheck )
import TcSimplify ( tcSimplify, tcSimplifyAndCheck, tcSimplifyToDicts )
import TcMonoType ( tcHsType, checkSigTyVars,
TcSigInfo(..), tcTySig, maybeSig, sigCtxt
)
......@@ -837,6 +837,9 @@ tcSpecSigs (SpecSig name poly_ty src_loc : sigs)
-- the spec-pragma-id at the same time
tcExpr (HsVar name) sig_ty `thenTc` \ (spec_expr, spec_lie) ->
-- Squeeze out any Methods (see comments with tcSimplifyToDicts)
tcSimplifyToDicts spec_lie `thenTc` \ (spec_lie1, spec_binds) ->
-- Just specialise "f" by building a SpecPragmaId binding
-- It is the thing that makes sure we don't prematurely
-- dead-code-eliminate the binding we are really interested in.
......@@ -844,8 +847,8 @@ tcSpecSigs (SpecSig name poly_ty src_loc : sigs)
-- Do the rest and combine
tcSpecSigs sigs `thenTc` \ (binds_rest, lie_rest) ->
returnTc (binds_rest `andMonoBinds` VarMonoBind spec_id spec_expr,
lie_rest `plusLIE` spec_lie)
returnTc (binds_rest `andMonoBinds` VarMonoBind spec_id (mkHsLet spec_binds spec_expr),
lie_rest `plusLIE` spec_lie1)
tcSpecSigs (other_sig : sigs) = tcSpecSigs sigs
tcSpecSigs [] = returnTc (EmptyMonoBinds, emptyLIE)
......
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