Encode the istr shape correctly. Issue #855

Author: brson

src/comp/middle/shape.rs

@@ -308,8 +308,13 @@ fn shape_of(ccx: &@crate_ctxt, t: ty::t) -> [u8] {
       ty::ty_str. {
         s += [shape_evec, 1u8, 1u8, 0u8, shape_u8];
       }
-      ty::ty_istr. { s += [shape_ivec, 1u8, 1u8, 0u8, shape_u8]; }
-
+      ty::ty_istr. {
+        s += [shape_ivec];
+        add_bool(s, true); // type is POD
+        let unit_ty = ty::mk_mach(ccx.tcx, ast::ty_u8);
+        add_size_hint(ccx, s, unit_ty);
+        add_substr(s, shape_of(ccx, unit_ty));
+      }
 
       ty::ty_tag(did, tps) {
         alt tag_kind(ccx, did) {

src/test/run-pass/istr.rs

@@ -16,8 +16,14 @@ fn test_heap_assign() {
     s = ~"AAAA";
 }
 
+fn test_heap_log() {
+    let s = ~"a big ol' string";
+    log s;
+}
+
 fn main() {
     test_stack_assign();
     test_heap_lit();
     test_heap_assign();
+    test_heap_log();
 }