shithub: mc

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Add test of string indexing, and make it work

    We didn't properly constrain stuff.

--- a/parse/infer.c

+++ b/parse/infer.c

@@ -153,6 +153,18 @@

     return s;

 }

+

+static void constrainby(Node *ctx, Type *a, Cstr *c)

+{

+    if (a->type == Tyvar) {

+        if (!a->cstrs)

+            a->cstrs = mkbs();

+        constrain(a, c);

+    } else if (!bshas(a->cstrs, c->cid)) {

+            fatal(ctx->line, "%s needs %s near %s", tystr(a), c->name, ctxstr(ctx));

+    }

+}

+

 static void mergecstrs(Node *ctx, Type *a, Type *b)

 {

     if (b->type == Tyvar) {

@@ -349,9 +361,10 @@

             settype(n, t);

             break;

         case Oidx:      /* @a[@b::tcint] -> @a */

-            t = mktyidxhack(n->line, type(args[1]));

+            t = mktyidxhack(n->line, mktyvar(n->line));

             unify(n, type(args[0]), t);

-            settype(n, type(args[1]));

+            constrainby(n, type(args[1]), cstrtab[Tcint]);

+            settype(n, tf(t->sub[0]));

             break;

         case Oslice:    /* @a[@b::tcint,@b::tcint] -> @a[,] */

             t = mktyidxhack(n->line, type(args[1]));

--- a/test/tests

+++ b/test/tests

@@ -31,6 +31,7 @@

 B structasn	E       42

 B log-and 	E       0

 B log-or  	E       1

+B str   	E       102

 F declmismatch

 F infermismatch

 F flow