Actually resolve trait bounds on impls. Closes #7266.

Author: msullivan

src/librustc/middle/typeck/check/mod.rs

@@ -609,6 +609,7 @@ pub fn check_item(ccx: @mut CrateCtxt, it: @ast::item) {
         for ms.iter().advance |m| {
             check_method(ccx, *m);
         }
+        vtable::resolve_impl(ccx, it);
       }
       ast::item_trait(_, _, ref trait_methods) => {
         for (*trait_methods).iter().advance |trait_method| {

src/librustc/middle/typeck/check/vtable.rs

@@ -478,6 +478,12 @@ pub fn location_info_for_expr(expr: @ast::expr) -> LocationInfo {
         id: expr.id
     }
 }
+pub fn location_info_for_item(item: @ast::item) -> LocationInfo {
+    LocationInfo {
+        span: item.span,
+        id: item.id
+    }
+}
 
 pub fn early_resolve_expr(ex: @ast::expr,
                           fcx: @mut FnCtxt,
@@ -661,6 +667,27 @@ fn resolve_expr(ex: @ast::expr,
     visit::visit_expr(ex, (fcx, v));
 }
 
+pub fn resolve_impl(ccx: @mut CrateCtxt, impl_item: @ast::item) {
+    let def_id = ast_util::local_def(impl_item.id);
+    match ty::impl_trait_ref(ccx.tcx, def_id) {
+        None => {},
+        Some(trait_ref) => {
+            let infcx = infer::new_infer_ctxt(ccx.tcx);
+            let vcx = VtableContext { ccx: ccx, infcx: infcx };
+            let trait_def = ty::lookup_trait_def(ccx.tcx, trait_ref.def_id);
+
+            let vtbls = lookup_vtables(&vcx,
+                                       &location_info_for_item(impl_item),
+                                       *trait_def.generics.type_param_defs,
+                                       &trait_ref.substs,
+                                       false);
+
+            // FIXME(#7450): Doesn't work cross crate
+            ccx.vtable_map.insert(impl_item.id, vtbls);
+        }
+    }
+}
+
 // Detect points where a trait-bounded type parameter is
 // instantiated, resolve the impls for the parameters.
 pub fn resolve_in_block(fcx: @mut FnCtxt, bl: &ast::blk) {