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| author |  Adam Chlipala <adamc@hcoop.net> | 2008-08-28 13:13:16 -0400 |
|---|---|---|
| committer | Adam Chlipala <adamc@hcoop.net> | 2008-08-28 13:13:16 -0400 |
| commit | 4637d2c9d9cf43d60c78a1c4a982cf37f46cd2d2 (patch) | |
| tree | 9b68e4e7e224f098c52e98574abf3a15aa3d223d /src | |
| parent | b3b35a26f843a75330c6536bc9502db679d50abd (diff) | |
Checking for well-formed 'val rec'
Diffstat (limited to 'src')
| -rw-r--r-- | src/elaborate.sml | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/elaborate.sml b/src/elaborate.sml index 9ea2ab58..746a06b7 100644 --- a/src/elaborate.sml +++ b/src/elaborate.sml @@ -1033,6 +1033,7 @@ datatype exp_error = | DuplicatePatField of ErrorMsg.span * string | Unresolvable of ErrorMsg.span * L'.con | OutOfContext of ErrorMsg.span * (L'.exp * L'.con) option + | IllegalRec of string * L'.exp fun expError env err = case err of @@ -1082,6 +1083,10 @@ fun expError env err = | Unresolvable (loc, c) => (ErrorMsg.errorAt loc "Can't resolve type class instance"; eprefaces' [("Class constraint", p_con env c)]) + | IllegalRec (x, e) => + (ErrorMsg.errorAt (#2 e) "Illegal 'val rec' righthand side (must be a function abstraction)"; + eprefaces' [("Variable", PD.string x), + ("Expression", p_exp env e)]) fun checkCon (env, denv) e c1 c2 = unifyCons (env, denv) c1 c2 @@ -2826,6 +2831,13 @@ fun elabDecl ((d, loc), (env, denv, gs : constraint list)) = end | L.DValRec vis => let + fun allowable (e, _) = + case e of + L.EAbs _ => true + | L.ECAbs (_, _, _, e) => allowable e + | L.EDisjoint (_, _, e) => allowable e + | _ => false + val (vis, gs) = ListUtil.foldlMap (fn ((x, co, e), gs) => let @@ -2849,6 +2861,10 @@ fun elabDecl ((d, loc), (env, denv, gs : constraint list)) = val gs2 = checkCon (env, denv) e' et c' in + if allowable e then + () + else + expError env (IllegalRec (x, e')); ((x, n, c', e'), gs1 @ enD gs2 @ gs) end) gs vis in |