shithub: mc

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Allow using the '==' operator on enum-style union.

--- a/mi/flatten.c

+++ b/mi/flatten.c

@@ -351,7 +351,22 @@

 static Node *

 comparecomplex(Flattenctx *s, Node *n, Op op)

 {

-	fatal(n, "Complex comparisons not yet supported\n");

+	Type *ty;

+	Node *l, *r, *e;

+

+	/* special case: unions with nullary constructors can be compared easily. */

+	ty = tybase(exprtype(n->expr.args[0]));

+	if (ty->type == Tyunion && isenum(ty)) {

+		l = mkexpr(n->loc, Outag, rval(s, n->expr.args[0]), NULL);

+		r = mkexpr(n->loc, Outag, rval(s, n->expr.args[1]), NULL);

+		l->expr.type = mktype(n->loc, Tyuint32);

+		r->expr.type = mktype(n->loc, Tyuint32);

+		e = mkexpr(n->loc, Oueq, l, r, NULL);

+		e->expr.type = mktype(n->loc, Tybool);

+		return e;

+	}

+	fatal(n, "cannot compare values of type %s for equality\n",

+	    tystr(exprtype(n->expr.args[0]));

 	return NULL;

 }