rustc: Convert field access on invalid types from an ICE to a fatal error

Closes #367

Author: brson

src/comp/middle/typeck.rs

@@ -1994,11 +1994,10 @@ fn check_expr(&@fn_ctxt fcx, &@ast::expr expr) {
                     write::ty_only_fixup(fcx, id, t);
                 }
                 case (_) {
-                    fcx.ccx.tcx.sess.span_unimpl(expr.span,
-                                                 "base type for expr_field \
-                                                  in typeck::check_expr: "
-                                                 + ty_to_str(fcx.ccx.tcx,
-                                                             base_t));
+                    auto t_err = resolve_type_vars_if_possible(fcx, base_t);
+                    auto msg = #fmt("attempted field access on type %s",
+                                    ty_to_str(fcx.ccx.tcx, t_err));
+                    fcx.ccx.tcx.sess.span_fatal(expr.span, msg);
                 }
             }
         }

src/test/compile-fail/direct-obj-fn-call.rs

@@ -1,4 +1,4 @@
-// error-pattern: base type for expr_field
+// error-pattern: attempted field access
 
 obj x() {
   fn hello() {

src/test/compile-fail/vec-field.rs

@@ -0,0 +1,10 @@
+// xfail-stage0
+// error-pattern:attempted field access on type vec\[int\]
+// issue #367
+
+fn f() {
+  auto v = [1];
+  log v.some_field_name; //type error
+}
+
+fn main() {}