cleanup: refactor away `ast::NodeIdAssigner`

5 files changed, 20 insertions, 57 deletions

diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 5b655522f34..2cc39412182 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -50,6 +50,7 @@ use session::Session;
 use std::collections::BTreeMap;
 use std::iter;
 use syntax::ast::*;
+use syntax::errors;
 use syntax::ptr::P;
 use syntax::codemap::{respan, Spanned};
 use syntax::parse::token;
@@ -60,7 +61,7 @@ use syntax_pos::Span;
 pub struct LoweringContext<'a> {
     crate_root: Option<&'static str>,
     // Use to assign ids to hir nodes that do not directly correspond to an ast node
-    id_assigner: &'a NodeIdAssigner,
+    sess: Option<&'a Session>,
     // As we walk the AST we must keep track of the current 'parent' def id (in
     // the form of a DefIndex) so that if we create a new node which introduces
     // a definition, then we can properly create the def id.
@@ -99,7 +100,6 @@ impl Resolver for DummyResolver {
 
 pub fn lower_crate(sess: &Session,
                    krate: &Crate,
-                   id_assigner: &NodeIdAssigner,
                    resolver: &mut Resolver)
                    -> hir::Crate {
     // We're constructing the HIR here; we don't care what we will
@@ -115,17 +115,17 @@ pub fn lower_crate(sess: &Session,
         } else {
             Some("std")
         },
-        id_assigner: id_assigner,
+        sess: Some(sess),
         parent_def: None,
         resolver: resolver,
     }.lower_crate(krate)
 }
 
 impl<'a> LoweringContext<'a> {
-    pub fn testing_context(id_assigner: &'a NodeIdAssigner, resolver: &'a mut Resolver) -> Self {
+    pub fn testing_context(resolver: &'a mut Resolver) -> Self {
         LoweringContext {
             crate_root: None,
-            id_assigner: id_assigner,
+            sess: None,
             parent_def: None,
             resolver: resolver,
         }
@@ -161,7 +161,12 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn next_id(&self) -> NodeId {
-        self.id_assigner.next_node_id()
+        self.sess.map(Session::next_node_id).unwrap_or(0)
+    }
+
+    fn diagnostic(&self) -> &errors::Handler {
+        self.sess.map(Session::diagnostic)
+                 .unwrap_or_else(|| panic!("this lowerer cannot emit diagnostics"))
     }
 
     fn str_to_ident(&self, s: &'static str) -> Name {
@@ -786,7 +791,7 @@ impl<'a> LoweringContext<'a> {
         if let Some(SelfKind::Explicit(..)) = sig.decl.get_self().map(|eself| eself.node) {
             match hir_sig.decl.get_self().map(|eself| eself.node) {
                 Some(hir::SelfKind::Value(..)) | Some(hir::SelfKind::Region(..)) => {
-                    self.id_assigner.diagnostic().span_err(sig.decl.inputs[0].ty.span,
+                    self.diagnostic().span_err(sig.decl.inputs[0].ty.span,
                         "the type placeholder `_` is not allowed within types on item signatures");
                 }
                 _ => {}
@@ -1212,7 +1217,7 @@ impl<'a> LoweringContext<'a> {
                             make_struct(self, e, &["RangeInclusive", "NonEmpty"],
                                                  &[("start", e1), ("end", e2)]),
 
-                        _ => panic!(self.id_assigner.diagnostic()
+                        _ => panic!(self.diagnostic()
                                         .span_fatal(e.span, "inclusive range with no end")),
                     };
                 }
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 77259cea24d..fdaf182c605 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -20,7 +20,7 @@ use ty::tls;
 use util::nodemap::{NodeMap, FnvHashMap};
 use mir::transform as mir_pass;
 
-use syntax::ast::{NodeId, NodeIdAssigner, Name};
+use syntax::ast::{NodeId, Name};
 use errors::{self, DiagnosticBuilder};
 use errors::emitter::{Emitter, BasicEmitter, EmitterWriter};
 use syntax::json::JsonEmitter;
@@ -272,6 +272,9 @@ impl Session {
 
         id
     }
+    pub fn next_node_id(&self) -> NodeId {
+        self.reserve_node_ids(1)
+    }
     pub fn diagnostic<'a>(&'a self) -> &'a errors::Handler {
         &self.parse_sess.span_diagnostic
     }
@@ -345,20 +348,6 @@ impl Session {
     }
 }
 
-impl NodeIdAssigner for Session {
-    fn next_node_id(&self) -> NodeId {
-        self.reserve_node_ids(1)
-    }
-
-    fn peek_node_id(&self) -> NodeId {
-        self.next_node_id.get().checked_add(1).unwrap()
-    }
-
-    fn diagnostic(&self) -> &errors::Handler {
-        self.diagnostic()
-    }
-}
-
 fn split_msg_into_multilines(msg: &str) -> Option<String> {
     // Conditions for enabling multi-line errors:
     if !msg.contains("mismatched types") &&
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index eb442c0a34e..980f0eeca18 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -49,13 +49,11 @@ use std::ffi::{OsString, OsStr};
 use std::fs;
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
-use syntax::ast::{self, NodeIdAssigner};
+use syntax::{ast, diagnostics, visit};
 use syntax::attr::{self, AttrMetaMethods};
-use syntax::diagnostics;
 use syntax::fold::Folder;
 use syntax::parse::{self, PResult, token};
 use syntax::util::node_count::NodeCounter;
-use syntax::visit;
 use syntax;
 use syntax_ext;
 
@@ -823,7 +821,7 @@ pub fn lower_and_resolve<'a>(sess: &Session,
 
         // Lower ast -> hir.
         let hir_forest = time(sess.time_passes(), "lowering ast -> hir", || {
-            hir_map::Forest::new(lower_crate(sess, krate, sess, &mut resolver), dep_graph)
+            hir_map::Forest::new(lower_crate(sess, krate, &mut resolver), dep_graph)
         });
 
         (ty::CrateAnalysis {
diff --git a/src/librustc_metadata/astencode.rs b/src/librustc_metadata/astencode.rs
index dc37bdf6322..7ef00b971c5 100644
--- a/src/librustc_metadata/astencode.rs
+++ b/src/librustc_metadata/astencode.rs
@@ -38,7 +38,6 @@ use rustc::ty::subst;
 use rustc::ty::{self, Ty, TyCtxt};
 
 use syntax::ast;
-use syntax::ast::NodeIdAssigner;
 use syntax::ptr::P;
 use syntax_pos;
 
@@ -56,7 +55,6 @@ use rustc_serialize::{Encodable, EncoderHelpers};
 
 #[cfg(test)] use std::io::Cursor;
 #[cfg(test)] use syntax::parse;
-#[cfg(test)] use syntax::ast::NodeId;
 #[cfg(test)] use rustc::hir::print as pprust;
 #[cfg(test)] use rustc::hir::lowering::{LoweringContext, DummyResolver};
 
@@ -1296,31 +1294,14 @@ impl FakeExtCtxt for parse::ParseSess {
 }
 
 #[cfg(test)]
-struct FakeNodeIdAssigner;
-
-#[cfg(test)]
-// It should go without saying that this may give unexpected results. Avoid
-// lowering anything which needs new nodes.
-impl NodeIdAssigner for FakeNodeIdAssigner {
-    fn next_node_id(&self) -> NodeId {
-        0
-    }
-
-    fn peek_node_id(&self) -> NodeId {
-        0
-    }
-}
-
-#[cfg(test)]
 fn mk_ctxt() -> parse::ParseSess {
     parse::ParseSess::new()
 }
 
 #[cfg(test)]
 fn with_testing_context<T, F: FnOnce(&mut LoweringContext) -> T>(f: F) -> T {
-    let assigner = FakeNodeIdAssigner;
     let mut resolver = DummyResolver;
-    let mut lcx = LoweringContext::testing_context(&assigner, &mut resolver);
+    let mut lcx = LoweringContext::testing_context(&mut resolver);
     f(&mut lcx)
 }
 
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index a352715b20b..cc033cec8b8 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -19,7 +19,6 @@ pub use util::ThinVec;
 use syntax_pos::{mk_sp, Span, DUMMY_SP, ExpnId};
 use codemap::{respan, Spanned};
 use abi::Abi;
-use errors;
 use parse::token::{self, keywords, InternedString};
 use print::pprust;
 use ptr::P;
@@ -362,15 +361,6 @@ pub const CRATE_NODE_ID: NodeId = 0;
 /// small, positive ids.
 pub const DUMMY_NODE_ID: NodeId = !0;
 
-pub trait NodeIdAssigner {
-    fn next_node_id(&self) -> NodeId;
-    fn peek_node_id(&self) -> NodeId;
-
-    fn diagnostic(&self) -> &errors::Handler {
-        panic!("this ID assigner cannot emit diagnostics")
-    }
-}
-
 /// The AST represents all type param bounds as types.
 /// typeck::collect::compute_bounds matches these against
 /// the "special" built-in traits (see middle::lang_items) and