diff options
Diffstat (limited to 'src/elaborate.sml')
| -rw-r--r-- | src/elaborate.sml | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/src/elaborate.sml b/src/elaborate.sml index 97b36a0b..6ffb7716 100644 --- a/src/elaborate.sml +++ b/src/elaborate.sml @@ -260,6 +260,19 @@ end + (* Wildcards are disallowed inside signatures. + * We use a flag to indicate when we are in a signature, + * with a helper function for entering this mode and properly backing out afterward. *) + val inSignature = ref false + fun enterSignature f = + let + val inS = !inSignature + in + inSignature := true; + (f () handle ex => (inSignature := inS; raise ex)) + before inSignature := inS + end + fun elabKind env (k, loc) = case k of L.KType => (L'.KType, loc) @@ -268,7 +281,7 @@ | L.KRecord k => (L'.KRecord (elabKind env k), loc) | L.KUnit => (L'.KUnit, loc) | L.KTuple ks => (L'.KTuple (map (elabKind env) ks), loc) - | L.KWild => kunif env loc + | L.KWild => if !inSignature then (kindError env (KDisallowedWildcard loc); kerror) else kunif env loc | L.KVar s => (case E.lookupK env s of NONE => @@ -531,11 +544,15 @@ end | L.CWild k => - let - val k' = elabKind env k - in - (cunif env (loc, k'), k', []) - end + if !inSignature then + (conError env (CDisallowedWildcard loc); + (cerror, kerror, [])) + else + let + val k' = elabKind env k + in + (cunif env (loc, k'), k', []) + end fun kunifsRemain k = case k of @@ -4146,7 +4163,7 @@ and elabDecl (dAll as (d, loc), (env, denv, gs)) = | L.DSgn (x, sgn) => let - val (sgn', gs') = elabSgn (env, denv) sgn + val (sgn', gs') = enterSignature (fn () => elabSgn (env, denv) sgn) val (env', n) = E.pushSgnNamed env x sgn' in ([(L'.DSgn (x, n, sgn'), loc)], (env', denv, enD gs' @ gs)) @@ -4171,7 +4188,7 @@ and elabDecl (dAll as (d, loc), (env, denv, gs)) = else () - val formal = Option.map (elabSgn (env, denv)) sgno + val formal = enterSignature (fn () => Option.map (elabSgn (env, denv)) sgno) val (str', sgn', gs') = case formal of @@ -4221,7 +4238,7 @@ and elabDecl (dAll as (d, loc), (env, denv, gs)) = end | NONE => let - val (sgn', gs') = elabSgn (env, denv) sgn + val (sgn', gs') = enterSignature (fn () => elabSgn (env, denv) sgn) val (env', n) = E.pushStrNamed env x sgn' |