re-introduce a cache for ast-ty-to-ty

It turns out that `ast_ty_to_ty` is supposed to be updating the `def`
after it finishes, but at some point in the past it stopped doing
so. This was never noticed because of the `ast_ty_to_ty_cache`, but that
cache was recently removed. This PR fixes the code to update the def
properly, but apparently that is not quite enough to make the operation
idempotent, so for now we reintroduce the cache too.

Fixes #33425.

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index fc048c86dc9ddff838ffe77d09451ffbb625b730..9cec3a517949635dd0c44897cfbad6d09220ef8f 100644 (file)
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -2544,6 +2544,8 @@ fn resolve_possibly_assoc_item(&mut self,
     /// returned value. See `hir::def::PathResolution` for more info.
     fn resolve_path(&mut self, id: NodeId, path: &Path, path_depth: usize, namespace: Namespace)
                     -> Result<PathResolution, bool /* true if an error was reported */ > {
+        debug!("resolve_path(id={:?} path={:?}, path_depth={:?})", id, path, path_depth);
+
         let span = path.span;
         let segments = &path.segments[..path.segments.len() - path_depth];
 

diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 725d40889ceecb3ba8dbaee4d044e1a3a62014a1..c8e247fb9181c7a3e733c0fbd6a556f26e13106c 100644 (file)
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -64,10 +64,10 @@
              ObjectLifetimeDefaultRscope, ShiftedRscope, BindingRscope,
              ElisionFailureInfo, ElidedLifetime};
 use util::common::{ErrorReported, FN_OUTPUT_NAME};
-use util::nodemap::FnvHashSet;
+use util::nodemap::{NodeMap, FnvHashSet};
 
 use rustc_const_math::ConstInt;
-
+use std::cell::RefCell;
 use syntax::{abi, ast};
 use syntax::codemap::{Span, Pos};
 use syntax::errors::DiagnosticBuilder;
@@ -81,6 +81,9 @@
 pub trait AstConv<'gcx, 'tcx> {
     fn tcx<'a>(&'a self) -> TyCtxt<'a, 'gcx, 'tcx>;
 
+    /// A cache used for the result of `ast_ty_to_ty_cache`
+    fn ast_ty_to_ty_cache(&self) -> &RefCell<NodeMap<Ty<'tcx>>>;
+
     /// Identify the type scheme for an item with a type, like a type
     /// alias, fn, or struct. This allows you to figure out the set of
     /// type parameters defined on the item.
@@ -1416,13 +1419,16 @@ fn base_def_to_ty(&self,
                       rscope: &RegionScope,
                       span: Span,
                       param_mode: PathParamMode,
-                      def: &Def,
+                      def: Def,
                       opt_self_ty: Option<Ty<'tcx>>,
                       base_segments: &[hir::PathSegment])
                       -> Ty<'tcx> {
         let tcx = self.tcx();
 
-        match *def {
+        debug!("base_def_to_ty(def={:?}, opt_self_ty={:?}, base_segments={:?})",
+               def, opt_self_ty, base_segments);
+
+        match def {
             Def::Trait(trait_def_id) => {
                 // N.B. this case overlaps somewhat with
                 // TyObjectSum, see that fn for details
@@ -1515,20 +1521,27 @@ pub fn finish_resolving_def_to_ty(&self,
                                       rscope: &RegionScope,
                                       span: Span,
                                       param_mode: PathParamMode,
-                                      def: &Def,
+                                      mut def: Def,
                                       opt_self_ty: Option<Ty<'tcx>>,
                                       base_segments: &[hir::PathSegment],
                                       assoc_segments: &[hir::PathSegment])
-                                      -> Ty<'tcx> {
+                                      -> (Ty<'tcx>, Def) {
+        debug!("finish_resolving_def_to_ty(def={:?}, \
+                base_segments={:?}, \
+                assoc_segments={:?})",
+               def,
+               base_segments,
+               assoc_segments);
         let mut ty = self.base_def_to_ty(rscope,
                                          span,
                                          param_mode,
                                          def,
                                          opt_self_ty,
                                          base_segments);
-        let mut def = *def;
+        debug!("finish_resolving_def_to_ty: base_def_to_ty returned {:?}", ty);
         // If any associated type segments remain, attempt to resolve them.
         for segment in assoc_segments {
+            debug!("finish_resolving_def_to_ty: segment={:?}", segment);
             if ty.sty == ty::TyError {
                 break;
             }
@@ -1540,7 +1553,7 @@ pub fn finish_resolving_def_to_ty(&self,
             ty = a_ty;
             def = a_def;
         }
-        ty
+        (ty, def)
     }
 
     /// Parses the programmer's textual representation of a type into our
@@ -1551,7 +1564,13 @@ pub fn ast_ty_to_ty(&self, rscope: &RegionScope, ast_ty: &hir::Ty) -> Ty<'tcx> {
 
         let tcx = self.tcx();
 
-        match ast_ty.node {
+        let cache = self.ast_ty_to_ty_cache();
+        match cache.borrow().get(&ast_ty.id) {
+            Some(ty) => { return ty; }
+            None => { }
+        }
+
+        let result_ty = match ast_ty.node {
             hir::TyVec(ref ty) => {
                 tcx.mk_slice(self.ast_ty_to_ty(rscope, &ty))
             }
@@ -1599,6 +1618,7 @@ pub fn ast_ty_to_ty(&self, rscope: &RegionScope, ast_ty: &hir::Ty) -> Ty<'tcx> {
                 self.conv_ty_poly_trait_ref(rscope, ast_ty.span, bounds)
             }
             hir::TyPath(ref maybe_qself, ref path) => {
+                debug!("ast_ty_to_ty: maybe_qself={:?} path={:?}", maybe_qself, path);
                 let path_res = if let Some(&d) = tcx.def_map.borrow().get(&ast_ty.id) {
                     d
                 } else if let Some(hir::QSelf { position: 0, .. }) = *maybe_qself {
@@ -1615,13 +1635,13 @@ pub fn ast_ty_to_ty(&self, rscope: &RegionScope, ast_ty: &hir::Ty) -> Ty<'tcx> {
                 let opt_self_ty = maybe_qself.as_ref().map(|qself| {
                     self.ast_ty_to_ty(rscope, &qself.ty)
                 });
-                let ty = self.finish_resolving_def_to_ty(rscope,
-                                                         ast_ty.span,
-                                                         PathParamMode::Explicit,
-                                                         &def,
-                                                         opt_self_ty,
-                                                         &path.segments[..base_ty_end],
-                                                         &path.segments[base_ty_end..]);
+                let (ty, _def) = self.finish_resolving_def_to_ty(rscope,
+                                                                 ast_ty.span,
+                                                                 PathParamMode::Explicit,
+                                                                 def,
+                                                                 opt_self_ty,
+                                                                 &path.segments[..base_ty_end],
+                                                                 &path.segments[base_ty_end..]);
 
                 if path_res.depth != 0 && ty.sty != ty::TyError {
                     // Write back the new resolution.
@@ -1675,7 +1695,11 @@ pub fn ast_ty_to_ty(&self, rscope: &RegionScope, ast_ty: &hir::Ty) -> Ty<'tcx> {
                 // handled specially and will not descend into this routine.
                 self.ty_infer(None, None, None, ast_ty.span)
             }
-        }
+        };
+
+        cache.borrow_mut().insert(ast_ty.id, result_ty);
+
+        result_ty
     }
 
     pub fn ty_of_arg(&self,

diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index f428023da9b8248628146e9220e6f5a3b25433be..6dfad749982b6e1886ce2b2869de28b2b1ce9a2a 100644 (file)
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -346,6 +346,8 @@ pub fn recurse(&mut self, blk: &hir::Block) -> UnsafetyState {
 
 #[derive(Clone)]
 pub struct FnCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
+    ast_ty_to_ty_cache: RefCell<NodeMap<Ty<'tcx>>>,
+
     body_id: ast::NodeId,
 
     // This flag is set to true if, during the writeback phase, we encounter
@@ -1262,6 +1264,10 @@ pub fn check_enum_variants<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
 impl<'a, 'gcx, 'tcx> AstConv<'gcx, 'tcx> for FnCtxt<'a, 'gcx, 'tcx> {
     fn tcx<'b>(&'b self) -> TyCtxt<'b, 'gcx, 'tcx> { self.tcx }
 
+    fn ast_ty_to_ty_cache(&self) -> &RefCell<NodeMap<Ty<'tcx>>> {
+        &self.ast_ty_to_ty_cache
+    }
+
     fn get_item_type_scheme(&self, _: Span, id: DefId)
                             -> Result<ty::TypeScheme<'tcx>, ErrorReported>
     {
@@ -1434,6 +1440,7 @@ pub fn new(inh: &'a Inherited<'a, 'gcx, 'tcx>,
                body_id: ast::NodeId)
                -> FnCtxt<'a, 'gcx, 'tcx> {
         FnCtxt {
+            ast_ty_to_ty_cache: RefCell::new(NodeMap()),
             body_id: body_id,
             writeback_errors: Cell::new(false),
             err_count_on_creation: inh.tcx.sess.err_count(),
@@ -3845,15 +3852,15 @@ pub fn resolve_ty_and_def_ufcs<'b>(&self,
         if path_res.depth == 0 {
             Some((opt_self_ty, &path.segments, path_res.base_def))
         } else {
-            let mut def = path_res.base_def;
+            let def = path_res.base_def;
             let ty_segments = path.segments.split_last().unwrap().1;
             let base_ty_end = path.segments.len() - path_res.depth;
-            let ty = AstConv::finish_resolving_def_to_ty(self, self, span,
-                                                         PathParamMode::Optional,
-                                                         &mut def,
-                                                         opt_self_ty,
-                                                         &ty_segments[..base_ty_end],
-                                                         &ty_segments[base_ty_end..]);
+            let (ty, _def) = AstConv::finish_resolving_def_to_ty(self, self, span,
+                                                                 PathParamMode::Optional,
+                                                                 def,
+                                                                 opt_self_ty,
+                                                                 &ty_segments[..base_ty_end],
+                                                                 &ty_segments[base_ty_end..]);
             let item_segment = path.segments.last().unwrap();
             let item_name = item_segment.identifier.name;
             let def = match self.resolve_ufcs(span, item_name, ty, node_id) {

diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 797a1509ebee51001ca797a884bc7a8e8e8b8465..f9a22e2a577b426b91f472f3dd7a8c5f8e18b299 100644 (file)
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -78,11 +78,12 @@
 use rustc::dep_graph::DepNode;
 use rustc::hir::map as hir_map;
 use util::common::{ErrorReported, MemoizationMap};
-use util::nodemap::FnvHashMap;
+use util::nodemap::{NodeMap, FnvHashMap};
 use {CrateCtxt, write_ty_to_tcx};
 
 use rustc_const_math::ConstInt;
 
+use std::cell::RefCell;
 use std::collections::HashSet;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::rc::Rc;
@@ -146,7 +147,10 @@ fn visit_item(&mut self, item: &hir::Item) {
 
 impl<'a,'tcx> CrateCtxt<'a,'tcx> {
     fn icx(&'a self, param_bounds: &'a GetTypeParameterBounds<'tcx>) -> ItemCtxt<'a,'tcx> {
-        ItemCtxt { ccx: self, param_bounds: param_bounds }
+        ItemCtxt {
+            ccx: self,
+            param_bounds: param_bounds,
+        }
     }
 
     fn cycle_check<F,R>(&self,
@@ -298,6 +302,10 @@ fn to_ty<RS:RegionScope>(&self, rs: &RS, ast_ty: &hir::Ty) -> Ty<'tcx> {
 impl<'a, 'tcx> AstConv<'tcx, 'tcx> for ItemCtxt<'a, 'tcx> {
     fn tcx<'b>(&'b self) -> TyCtxt<'b, 'tcx, 'tcx> { self.ccx.tcx }
 
+    fn ast_ty_to_ty_cache(&self) -> &RefCell<NodeMap<Ty<'tcx>>> {
+        &self.ccx.ast_ty_to_ty_cache
+    }
+
     fn get_item_type_scheme(&self, span: Span, id: DefId)
                             -> Result<ty::TypeScheme<'tcx>, ErrorReported>
     {

diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index b88b3c9802d30bbd3bff3273aa824ae3ba3b1f58..f41da95c1353700432ac6246b82b5eed3b569826 100644 (file)
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -116,6 +116,7 @@
 use syntax::abi::Abi;
 
 use std::cell::RefCell;
+use util::nodemap::NodeMap;
 
 // NB: This module needs to be declared first so diagnostics are
 // registered before they are used.
@@ -136,7 +137,9 @@ pub struct TypeAndSubsts<'tcx> {
 }
 
 pub struct CrateCtxt<'a, 'tcx: 'a> {
-    // A mapping from method call sites to traits that have that method.
+    ast_ty_to_ty_cache: RefCell<NodeMap<Ty<'tcx>>>,
+
+    /// A mapping from method call sites to traits that have that method.
     pub trait_map: hir::TraitMap,
 
     /// A vector of every trait accessible in the whole crate
@@ -334,6 +337,7 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                              -> CompileResult {
     let time_passes = tcx.sess.time_passes();
     let ccx = CrateCtxt {
+        ast_ty_to_ty_cache: RefCell::new(NodeMap()),
         trait_map: trait_map,
         all_traits: RefCell::new(None),
         stack: RefCell::new(Vec::new()),

diff --git a/src/test/run-pass/associated-types-in-bound-type-arg.rs b/src/test/run-pass/associated-types-in-bound-type-arg.rs
new file mode 100644 (file)
index 0000000..18803d1
--- /dev/null
+++ b/src/test/run-pass/associated-types-in-bound-type-arg.rs
@@ -0,0 +1,26 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test the case where we resolve `C::Result` and the trait bound
+// itself includes a `Self::Item` shorthand.
+//
+// Regression test for issue #33425.
+
+trait ParallelIterator {
+    type Item;
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+        where C: Consumer<Self::Item>;
+}
+
+pub trait Consumer<ITEM> {
+    type Result;
+}
+
+fn main() { }