refactor to store the types during inference in tables in the fcx

this is a step towards separating out the repr. of
types during inference from the repr. in later stages.

src/rustc/middle/ast_map.rs

@@ -1,6 +1,7 @@
 import std::map;
 import std::map::hashmap;
 import syntax::ast::*;
+import syntax::print::pprust;
 import syntax::ast_util;
 import syntax::ast_util::inlined_item_methods;
 import syntax::{visit, codemap};
@@ -20,6 +21,14 @@ fn path_to_str_with_sep(p: path, sep: str) -> str {
     str::connect(strs, sep)
 }
 
+fn path_ident_to_str(p: path, i: ident) -> str {
+    if vec::is_empty(p) {
+        i
+    } else {
+        #fmt["%s::%s", path_to_str(p), i]
+    }
+}
+
 fn path_to_str(p: path) -> str {
     path_to_str_with_sep(p, "::")
 }
@@ -224,6 +233,49 @@ fn map_expr(ex: @expr, cx: ctx, v: vt) {
     visit::visit_expr(ex, cx, v);
 }
 
+fn node_id_to_str(map: map, id: node_id) -> str {
+    alt map.find(id) {
+      none {
+        #fmt["unknown node (id=%d)", id]
+      }
+      some(node_item(item, path)) {
+        #fmt["item %s (id=%?)", path_ident_to_str(*path, item.ident), id]
+      }
+      some(node_native_item(item, abi, path)) {
+        #fmt["native item %s with abi %? (id=%?)",
+             path_ident_to_str(*path, item.ident), abi, id]
+      }
+      some(node_method(m, impl_did, path)) {
+        #fmt["method %s in %s (id=%?)",
+             m.ident, path_to_str(*path), id]
+      }
+      some(node_variant(variant, def_id, path)) {
+        #fmt["variant %s in %s (id=%?)",
+             variant.node.name, path_to_str(*path), id]
+      }
+      some(node_expr(expr)) {
+        #fmt["expr %s (id=%?)",
+             pprust::expr_to_str(expr), id]
+      }
+      some(node_export(_, path)) {
+        #fmt["export %s (id=%?)", // FIXME: add more info here
+             path_to_str(*path), id]
+      }
+      some(node_arg(_, _)) { // FIXME: add more info here
+        #fmt["arg (id=%?)", id]
+      }
+      some(node_local(_)) { // FIXME: add more info here
+        #fmt["local (id=%?)", id]
+      }
+      some(node_ctor(_, _)) { // FIXME: add more info here
+        #fmt["node_ctor (id=%?)", id]
+      }
+      some(node_block(_)) {
+        #fmt["block"]
+      }
+    }
+}
+
 // Local Variables:
 // mode: rust
 // fill-column: 78;

src/rustc/middle/ty.rs

@@ -1561,7 +1561,8 @@ fn constrs_eq(cs: [@constr], ds: [@constr]) -> bool {
 fn node_id_to_type(cx: ctxt, id: ast::node_id) -> t {
     alt smallintmap::find(*cx.node_types, id as uint) {
        some(t) { t }
-       none { cx.sess.bug(#fmt("node_id_to_type: unbound node ID %?", id)); }
+       none { cx.sess.bug(#fmt("node_id_to_type: unbound node ID %s",
+                               ast_map::node_id_to_str(cx.items, id))); }
     }
 }