Reviewer comments

src/librustc/diagnostics.rs

@@ -151,9 +151,6 @@ register_diagnostics!(
     E0172,
     E0173,
     E0174,
-    E0175,
-    E0176,
     E0177,
-    E0178,
-    E0179
+    E0178
 )

src/librustc/middle/resolve_lifetime.rs

@@ -496,7 +496,7 @@ fn early_bound_lifetime_names(generics: &ast::Generics) -> Vec<ast::Name> {
                 &ast::BoundPredicate(ast::WhereBoundPredicate{ref bounds, ..}) => {
                     visit::walk_ty_param_bounds_helper(&mut collector, bounds);
                 }
-                _ => {}
+                &ast::EqPredicate(_) => unimplemented!()
             }
         }
     }

src/librustc/middle/typeck/astconv.rs

@@ -367,13 +367,11 @@ fn create_substs_for_ast_path<'tcx,AC,RS>(
         }
     }
 
-    let mut matched_assoc = 0u;
     for formal_assoc in decl_generics.types.get_slice(AssocSpace).iter() {
         let mut found = false;
         for &(ident, ty) in assoc_bindings.iter() {
             if formal_assoc.name.ident() == ident {
                 substs.types.push(AssocSpace, ty);
-                matched_assoc += 1;
                 found = true;
                 break;
             }
@@ -385,23 +383,17 @@ fn create_substs_for_ast_path<'tcx,AC,RS>(
                                                formal_assoc.def_id) {
                 Some(ty) => {
                     substs.types.push(AssocSpace, ty);
-                    matched_assoc += 1;
                 }
                 None => {
-                    span_err!(this.tcx().sess, span, E0179,
+                    substs.types.push(AssocSpace, ty::mk_err());
+                    span_err!(this.tcx().sess, span, E0171,
                               "missing type for associated type `{}`",
                               token::get_ident(formal_assoc.name.ident()));
                 }
             }
         }
     }
 
-    if decl_generics.types.get_slice(AssocSpace).len() != matched_assoc {
-        span_err!(tcx.sess, span, E0171,
-                  "wrong number of associated type parameters: expected {}, found {}",
-                  decl_generics.types.get_slice(AssocSpace).len(), matched_assoc);
-    }
-
     for &(ident, _) in assoc_bindings.iter() {
         let mut formal_idents = decl_generics.types.get_slice(AssocSpace)
                                 .iter().map(|t| t.name.ident());

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

@@ -5141,18 +5141,12 @@ pub fn instantiate_path<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
             }
 
             Some(space) => {
-                let trait_def_id = match def {
-                    def::DefTrait(did) => Some(did),
-                    _ => None
-                };
                 push_explicit_parameters_from_segment_to_substs(fcx,
                                                                 space,
                                                                 path.span,
                                                                 type_defs,
                                                                 region_defs,
                                                                 segment,
-                                                                trait_def_id,
-                                                                path.span,
                                                                 &mut substs);
             }
         }
@@ -5239,14 +5233,12 @@ pub fn instantiate_path<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
         type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>,
         region_defs: &VecPerParamSpace<ty::RegionParameterDef>,
         segment: &ast::PathSegment,
-        trait_def_id: Option<DefId>,
-        path_span: Span,
         substs: &mut Substs<'tcx>)
     {
         match segment.parameters {
             ast::AngleBracketedParameters(ref data) => {
                 push_explicit_angle_bracketed_parameters_from_segment_to_substs(
-                    fcx, space, type_defs, region_defs, data, trait_def_id, path_span, substs);
+                    fcx, space, type_defs, region_defs, data, substs);
             }
 
             ast::ParenthesizedParameters(ref data) => {
@@ -5262,8 +5254,6 @@ pub fn instantiate_path<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
         type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>,
         region_defs: &VecPerParamSpace<ty::RegionParameterDef>,
         data: &ast::AngleBracketedParameterData,
-        trait_def_id: Option<DefId>,
-        path_span: Span,
         substs: &mut Substs<'tcx>)
     {
         {
@@ -5285,49 +5275,11 @@ pub fn instantiate_path<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
             }
         }
 
-        if let Some(trait_def_id) = trait_def_id {
-            let ref items = fcx.tcx().trait_item_def_ids.borrow()[trait_def_id];
-            let mut assoc_tys = Vec::new();
-            for item in items.iter() {
-                if let &ty::ImplOrTraitItemId::TypeTraitItemId(id) = item {
-                    if let ty::ImplOrTraitItem::TypeTraitItem(ref ty) =
-                      fcx.tcx().impl_or_trait_items.borrow()[id] {
-                        assoc_tys.push(ty.clone());
-                    }
-                }
-            }
-
-            if data.bindings.len() > assoc_tys.len() {
-                span_err!(fcx.tcx().sess, data.bindings[assoc_tys.len()].span, E0174,
-                    "too many type equality constraints provided: \
-                     expected at most {} constraint(s), \
-                     found {} constraint(s)",
-                     assoc_tys.len(), data.types.len());
-                substs.types.truncate(space, 0);
-            } else if data.bindings.len() > 0 {
-                for assoc_ty in assoc_tys.iter() {
-                    let mut matched = false;
-                    for binding in data.bindings.iter() {
-                        if assoc_ty.name.ident() == binding.ident {
-                            let t = fcx.to_ty(&*binding.ty);
-                            substs.types.push(space, t);
-                            matched = true;
-                            break;
-                        }
-                    }
-                    if !matched {
-                        span_err!(fcx.tcx().sess, path_span, E0176,
-                            "missing type equality constraint for associated type: {}",
-                             assoc_ty.name);
-                        substs.types.truncate(space, 0);
-                        break;
-                    }
-                }
-            }
-        } else if data.bindings.len() > 0 {
-            span_err!(fcx.tcx().sess, path_span, E0175,
-                "type equality constraints provided on a non-trait type");
-            substs.types.truncate(space, 0);
+        if data.bindings.len() > 0 {
+            span_err!(fcx.tcx().sess, data.bindings[0].span, E0174,
+                      "unexpected binding of associated item in expression path \
+                       (only allowed in type paths)");
+            substs.types.truncate(subst::ParamSpace::AssocSpace, 0);
         }
 
         {

src/librustc/middle/typeck/collect.rs

@@ -1839,7 +1839,7 @@ fn ty_generics<'tcx,AC>(this: &AC,
                 let trait_def = ty::lookup_trait_def(this.tcx(), trait_def_id);
                 let associated_type_defs = trait_def.generics.types.get_slice(subst::AssocSpace);
 
-                // Find any assocaited type bindings in the bound.
+                // Find any associated type bindings in the bound.
                 let ref segments = ast_trait_ref.trait_ref.path.segments;
                 let bindings = segments[segments.len() -1].parameters.bindings();
 

src/test/compile-fail/assoc-eq-expr-path.rs

@@ -0,0 +1,23 @@
+// Copyright 2014 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.
+
+// Check that an associated type cannot be bound in an expression path.
+
+#![feature(associated_types)]
+
+impl Foo for int {
+    type A = uint;
+    fn bar() -> int { 42 }
+}
+
+pub fn main() {
+    let x: int = Foo::<A=uint>::bar();
+    //~^ERROR unexpected binding of associated item in expression path
+}