Fix overlapping match statements (thanks Mako)

	We were overly aggressive in unifying wildcards.

1 files changed, 16 insertions, 17 deletions

diff --git a/mi/match.c b/mi/match.c
index a904c60..86db1c5 100644
--- a/mi/match.c
+++ b/mi/match.c
@@ -16,6 +16,7 @@
 typedef struct Dtree Dtree;
 struct Dtree {
 	int id;
+	int obscured;
 	Srcloc loc;
 
 	/* values for matching */
@@ -361,14 +362,13 @@ addwildrec(Srcloc loc, Type *ty, Dtree *start, Dtree *accept, Dtree ***end, size
 		for (i = 0; i < ty->nmemb; i++) {
 			uc = ty->udecls[i];
 			next = dtbytag(start, uc);
-			if (next) {
-				if (uc->etype) {
-					if (addwildrec(loc, uc->etype, next, accept, end, nend))
-						ret = 1;
-				} else {
-					lappend(end, nend, next);
-				}
-			}
+			if (!next)
+				continue;
+
+			if (uc->etype && addwildrec(loc, uc->etype, next, accept, end, nend))
+				ret = 1;
+			else
+				lappend(end, nend, next);
 		}
 		if (!start->any) {
 			start->any = accept;
@@ -408,10 +408,8 @@ addunion(Node *pat, Node *val, Dtree *start, Dtree *accept, Node ***cap, size_t
 	Dtree *next;
 	Ucon *uc;
 
-	if (start->any) {
+	if (start->any)
 		lappend(end, nend, start->any);
-		return 0;
-	}
 
 	uc = finducon(tybase(exprtype(pat)), pat->expr.args[0]);
 	next = dtbytag(start, uc);
@@ -434,13 +432,15 @@ addunion(Node *pat, Node *val, Dtree *start, Dtree *accept, Node ***cap, size_t
 	lappend(&start->pat, &start->npat, tagid);
 	if (uc->etype) {
 		next = mkdtree(pat->loc, genlbl(pat->loc));
+		next->obscured = (start->obscured || start->any != NULL);
 		lappend(&start->next, &start->nnext, next);
 		addpat(pat->expr.args[1], uvalue(val, uc->etype), next, accept, cap, ncap, end, nend);
 	} else {
+		accept->obscured = (start->obscured || start->any != NULL);
 		lappend(&start->next, &start->nnext, accept);
 		lappend(end, nend, accept);
 	}
-	return 1;
+	return !start->obscured && start->any == NULL;
 }
 
 static int
@@ -502,12 +502,10 @@ addlit(Node *pat, Node *val, Dtree *start, Dtree *accept, Node ***cap, size_t *n
 	if (pat->expr.args[0]->lit.littype == Lstr) {
 		return addstr(pat, val, start, accept, cap, ncap, end, nend);
 	} else {
-		/* if we already have a match, we're not adding a new node */
-		if (start->any) {
+		if (start->any)
 			lappend(end, nend, start->any);
-			return 0;
-		}
 
+		/* if we already have a match, we're not adding a new node */
 		for (i = 0; i < start->npat; i++) {
 			if (liteq(start->pat[i]->expr.args[0], pat->expr.args[0])) {
 				lappend(end, nend, start->next[i]);
@@ -520,10 +518,11 @@ addlit(Node *pat, Node *val, Dtree *start, Dtree *accept, Node ***cap, size_t *n
 			start->load = val;
 			start->nconstructors = nconstructors(exprtype(pat));
 		}
+		accept->obscured = (start->obscured || start->any != NULL);
 		lappend(&start->pat, &start->npat, pat);
 		lappend(&start->next, &start->nnext, accept);
 		lappend(end, nend, accept);
-		return 1;
+		return !start->obscured && start->any == NULL;
 	}
 }