Replace no_ord_impl with orderable.

Similar to the previous commit, this replaces `newtype_index`'s opt-out
`no_ord_impl` attribute with the opt-in `orderable` attribute.

Author: nnethercote

compiler/rustc_ast/src/ast.rs

@@ -2574,6 +2574,7 @@ pub enum AttrStyle {
 }
 
 rustc_index::newtype_index! {
+    #[orderable]
     #[debug_format = "AttrId({})"]
     pub struct AttrId {}
 }

compiler/rustc_ast/src/node_id.rs

@@ -9,6 +9,7 @@ rustc_index::newtype_index! {
     ///
     /// [`DefId`]: rustc_span::def_id::DefId
     #[encodable]
+    #[orderable]
     #[debug_format = "NodeId({})"]
     pub struct NodeId {
         /// The [`NodeId`] used to represent the root of the crate.

compiler/rustc_borrowck/src/constraints/mod.rs

@@ -122,6 +122,7 @@ rustc_index::newtype_index! {
 }
 
 rustc_index::newtype_index! {
+    #[orderable]
     #[debug_format = "ConstraintSccIndex({})"]
     pub struct ConstraintSccIndex {}
 }

compiler/rustc_borrowck/src/dataflow.rs

@@ -109,6 +109,7 @@ impl_visitable! {
 }
 
 rustc_index::newtype_index! {
+    #[orderable]
     #[debug_format = "bw{}"]
     pub struct BorrowIndex {}
 }

compiler/rustc_borrowck/src/location.rs

@@ -20,6 +20,7 @@ pub struct LocationTable {
 }
 
 rustc_index::newtype_index! {
+    #[orderable]
     #[debug_format = "LocationIndex({})"]
     pub struct LocationIndex {}
 }

compiler/rustc_borrowck/src/region_infer/values.rs

@@ -90,6 +90,7 @@ impl RegionValueElements {
 rustc_index::newtype_index! {
     /// A single integer representing a `Location` in the MIR control-flow
     /// graph. Constructed efficiently from `RegionValueElements`.
+    #[orderable]
     #[debug_format = "PointIndex({})"]
     pub struct PointIndex {}
 }

compiler/rustc_data_structures/src/graph/dominators/mod.rs

@@ -23,6 +23,7 @@ struct PreOrderFrame<Iter> {
 }
 
 rustc_index::newtype_index! {
+    #[orderable]
     struct PreorderIndex {}
 }
 

compiler/rustc_hir/src/hir_id.rs

@@ -157,6 +157,7 @@ rustc_index::newtype_index! {
     /// tree or hash map.
     #[derive(HashStable_Generic)]
     #[encodable]
+    #[orderable]
     pub struct ItemLocalId {}
 }
 

compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs

@@ -198,6 +198,7 @@ impl<'tcx> InherentOverlapChecker<'tcx> {
             // entire graph when there are many connected regions.
 
             rustc_index::newtype_index! {
+                #[orderable]
                 pub struct RegionId {}
             }
 

compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs

@@ -4,11 +4,13 @@ use rustc_middle::ty::error::TypeError;
 use std::cmp;
 
 rustc_index::newtype_index! {
+    #[orderable]
     #[debug_format = "ExpectedIdx({})"]
     pub(crate) struct ExpectedIdx {}
 }
 
 rustc_index::newtype_index! {
+    #[orderable]
     #[debug_format = "ProvidedIdx({})"]
     pub(crate) struct ProvidedIdx {}
 }