rustc: rework stability to be on-demand for type-directed lookup.

Author: eddyb

src/etc/generate-deriving-span-tests.py

@@ -37,8 +37,6 @@
 
 // This file was auto-generated using 'src/etc/generate-deriving-span-tests.py'
 
-extern crate rand;
-
 {error_deriving}
 struct Error;
 {code}
@@ -106,7 +104,6 @@ def write_file(name, string):
 ALL = STRUCT | ENUM
 
 traits = {
-    'Zero': (STRUCT, [], 1),
     'Default': (STRUCT, [], 1),
     'FromPrimitive': (0, [], 0), # only works for C-like enums
 
@@ -116,7 +113,7 @@ def write_file(name, string):
 
 for (trait, supers, errs) in [('Clone', [], 1),
                               ('PartialEq', [], 2),
-                              ('PartialOrd', ['PartialEq'], 8),
+                              ('PartialOrd', ['PartialEq'], 9),
                               ('Eq', ['PartialEq'], 1),
                               ('Ord', ['Eq', 'PartialOrd', 'PartialEq'], 1),
                               ('Debug', [], 1),

src/librustc/dep_graph/dep_node.rs

@@ -90,7 +90,7 @@ pub enum DepNode<D: Clone + Debug> {
     RvalueCheck(D),
     Reachability,
     DeadCheck,
-    StabilityCheck,
+    StabilityCheck(D),
     LateLintCheck,
     TransCrate,
     TransCrateItem(D),
@@ -189,7 +189,6 @@ impl<D: Clone + Debug> DepNode<D> {
             Privacy => Some(Privacy),
             Reachability => Some(Reachability),
             DeadCheck => Some(DeadCheck),
-            StabilityCheck => Some(StabilityCheck),
             LateLintCheck => Some(LateLintCheck),
             TransCrate => Some(TransCrate),
             TransWriteMetadata => Some(TransWriteMetadata),
@@ -217,6 +216,7 @@ impl<D: Clone + Debug> DepNode<D> {
             Mir(ref d) => op(d).map(Mir),
             BorrowCheck(ref d) => op(d).map(BorrowCheck),
             RvalueCheck(ref d) => op(d).map(RvalueCheck),
+            StabilityCheck(ref d) => op(d).map(StabilityCheck),
             TransCrateItem(ref d) => op(d).map(TransCrateItem),
             TransInlinedItem(ref d) => op(d).map(TransInlinedItem),
             AssociatedItems(ref d) => op(d).map(AssociatedItems),