---

yaml
---
r: 224251
b: refs/heads/beta
c: 01dcb3b
h: refs/heads/master
i:
  224249: 5f02029
  224247: 33fe925
v: v3

Author: jroesch

[refs]

@@ -23,7 +23,7 @@ refs/tags/0.9: 36870b185fc5f5486636d4515f0e22677493f225
 refs/tags/0.10: ac33f2b15782272ae348dbd7b14b8257b2148b5a
 refs/tags/0.11.0: e1247cb1d0d681be034adb4b558b5a0c0d5720f9
 refs/tags/0.12.0: f0c419429ef30723ceaf6b42f9b5a2aeb5d2e2d1
-refs/heads/beta: d782e35c30a9642afe4ea28614efc08025694b1b
+refs/heads/beta: 01dcb3bdf0fd779208c915d704ae634beb5c4448
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: 938f5d7af401e2d8238522fed4a612943b6e77fd
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f

branches/beta/src/librustc/middle/infer/error_reporting.rs

@@ -893,8 +893,8 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
             self.report_inference_failure(vo.clone());
         }
         self.give_suggestion(same_regions);
-        for &(ref trace, terr) in trace_origins {
-            self.report_and_explain_type_error(trace.clone(), &terr);
+        for &(ref trace, ref terr) in trace_origins {
+            self.report_and_explain_type_error(trace.clone(), terr);
         }
     }
 

branches/beta/src/librustc/middle/infer/mod.rs

@@ -40,6 +40,7 @@ use syntax::codemap;
 use syntax::codemap::{Span, DUMMY_SP};
 use util::nodemap::{FnvHashMap, NodeMap};
 
+use ast_map;
 use self::combine::CombineFields;
 use self::region_inference::{RegionVarBindings, RegionSnapshot};
 use self::error_reporting::ErrorReporting;
@@ -72,7 +73,7 @@ pub struct InferCtxt<'a, 'tcx: 'a> {
     // We instantiate UnificationTable with bounds<Ty> because the
     // types that might instantiate a general type variable have an
     // order, represented by its upper and lower bounds.
-    type_variables: RefCell<type_variable::TypeVariableTable<'tcx>>,
+    pub type_variables: RefCell<type_variable::TypeVariableTable<'tcx>>,
 
     // Map from integral variable to the kind of integer it represents
     int_unification_table: RefCell<UnificationTable<ty::IntVid>>,
@@ -690,7 +691,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         variables.extend(unbound_ty_vars);
         variables.extend(unbound_int_vars);
         variables.extend(unbound_float_vars);
-        
+
         return variables;
     }
 
@@ -1047,15 +1048,36 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     }
 
     pub fn type_vars_for_defs(&self,
+                              span: Span,
+                              // substs: Substs,
                               defs: &[ty::TypeParameterDef<'tcx>])
                               -> Vec<ty::Ty<'tcx>> {
+
+        fn definition_span<'tcx>(tcx: &ty::ctxt<'tcx>, def_id: ast::DefId) -> Span {
+            let parent = tcx.map.get_parent(def_id.node);
+            debug!("definition_span def_id={:?} parent={:?} node={:?} parent_node={:?}",
+                def_id, parent, tcx.map.find(def_id.node), tcx.map.find(parent));
+            match tcx.map.find(parent) {
+                None => DUMMY_SP,
+                Some(ref node) => match *node {
+                    ast_map::NodeItem(ref item) => item.span,
+                    ast_map::NodeForeignItem(ref item) => item.span,
+                    ast_map::NodeTraitItem(ref item) => item.span,
+                    ast_map::NodeImplItem(ref item) => item.span,
+                    _ => DUMMY_SP
+                }
+            }
+        }
+
         let mut substs = Substs::empty();
         let mut vars = Vec::with_capacity(defs.len());
 
         for def in defs.iter() {
             let default = def.default.map(|default| {
                 type_variable::Default {
-                    ty: default
+                    ty: default,
+                    origin_span: span,
+                    definition_span: definition_span(self.tcx, def.def_id)
                 }
             });
             //.subst(self.tcx, &substs)
@@ -1077,7 +1099,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let mut type_params = subst::VecPerParamSpace::empty();
 
         for space in subst::ParamSpace::all().iter() {
-            type_params.replace(*space, self.type_vars_for_defs(generics.types.get_slice(*space)))
+            type_params.replace(*space,
+                                self.type_vars_for_defs(span, generics.types.get_slice(*space)))
         }
 
         let region_params =
@@ -1102,7 +1125,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         assert!(generics.regions.len(subst::FnSpace) == 0);
 
         let type_parameter_defs = generics.types.get_slice(subst::TypeSpace);
-        let type_parameters = self.type_vars_for_defs(type_parameter_defs);
+        let type_parameters = self.type_vars_for_defs(span, type_parameter_defs);
 
         let region_param_defs = generics.regions.get_slice(subst::TypeSpace);
         let regions = self.region_vars_for_defs(span, region_param_defs);
@@ -1344,13 +1367,13 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
 
     pub fn report_conflicting_default_types(&self,
                                    span: Span,
-                                   expected: Ty<'tcx>,
-                                   actual: Ty<'tcx>) {
+                                   expected: type_variable::Default<'tcx>,
+                                   actual: type_variable::Default<'tcx>) {
         let trace = TypeTrace {
             origin: Misc(span),
             values: Types(ty::expected_found {
-                expected: expected,
-                found: actual
+                expected: expected.ty,
+                found: actual.ty
             })
         };
 

branches/beta/src/librustc/middle/infer/type_variable.rs

@@ -11,8 +11,9 @@
 pub use self::RelationDir::*;
 use self::TypeVariableValue::*;
 use self::UndoEntry::*;
-
 use middle::ty::{self, Ty};
+use syntax::codemap::Span;
+
 use std::cmp::min;
 use std::marker::PhantomData;
 use std::mem;
@@ -38,9 +39,13 @@ enum TypeVariableValue<'tcx> {
 
 // We will use this to store the required information to recapitulate what happened when
 // an error occurs.
-#[derive(Clone)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct Default<'tcx> {
-    pub ty: Ty<'tcx>
+    pub ty: Ty<'tcx>,
+    /// The span where the default was incurred
+    pub origin_span: Span,
+    /// The definition that the default originates from
+    pub definition_span: Span
 }
 
 pub struct Snapshot {

branches/beta/src/librustc/middle/ty.rs

@@ -54,6 +54,7 @@ use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangIte
 use middle::region;
 use middle::resolve_lifetime;
 use middle::infer;
+use middle::infer::type_variable;
 use middle::pat_util;
 use middle::region::RegionMaps;
 use middle::stability;
@@ -2068,7 +2069,7 @@ pub enum TypeError<'tcx> {
     ConvergenceMismatch(ExpectedFound<bool>),
     ProjectionNameMismatched(ExpectedFound<ast::Name>),
     ProjectionBoundsLength(ExpectedFound<usize>),
-    terr_ty_param_default_mismatch(expected_found<Ty<'tcx>>)
+    TyParamDefaultMismatch(ExpectedFound<Ty<'tcx>>)
 }
 
 /// Bounds suitable for an existentially quantified type parameter
@@ -5083,9 +5084,9 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
                        values.found)
             },
             terr_ty_param_default_mismatch(ref values) => {
-                write!(f, "conflicting type parameter defaults {} {}",
-                       values.expected,
-                       values.found)
+                write!(f, "conflicting type parameter defaults {} and {}",
+                       values.expected.ty,
+                       values.found.ty)
             }
         }
     }
@@ -5405,7 +5406,7 @@ impl<'tcx> ctxt<'tcx> {
     pub fn note_and_explain_type_err(&self, err: &TypeError<'tcx>, sp: Span) {
         use self::TypeError::*;
 
-        match *err {
+        match err.clone() {
             RegionsDoesNotOutlive(subregion, superregion) => {
                 self.note_and_explain_region("", subregion, "...");
                 self.note_and_explain_region("...does not necessarily outlive ",
@@ -5444,10 +5445,21 @@ impl<'tcx> ctxt<'tcx> {
                                   using it as a trait object"));
                 }
             },
-            terr_ty_param_default_mismatch(expected) => {
+            terr_ty_param_default_mismatch(values) => {
+                let expected = values.expected;
+                let found = values.found;
                 self.sess.span_note(sp,
-                    &format!("found conflicting defaults {:?} {:?}",
-                             expected.expected, expected.found))
+                    &format!("conflicting type parameter defaults {} and {}",
+                             expected.ty,
+                             found.ty));
+                self.sess.span_note(expected.definition_span,
+                    &format!("...a default was defined"));
+                self.sess.span_note(expected.origin_span,
+                    &format!("...that was applied to an unconstrained type variable here"));
+                self.sess.span_note(found.definition_span,
+                    &format!("...a second default was defined"));
+                self.sess.span_note(found.origin_span,
+                    &format!("...that also applies to the same type variable here"));
             }
             _ => {}
         }

branches/beta/src/librustc_typeck/astconv.rs

@@ -111,7 +111,7 @@ pub trait AstConv<'tcx> {
     }
 
     /// What type should we use when a type is omitted?
-    fn ty_infer(&self, default: Option<Ty<'tcx>>, span: Span) -> Ty<'tcx>;
+    fn ty_infer(&self, default: Option<ty::TypeParameterDef<'tcx>>, span: Span) -> Ty<'tcx>;
 
     /// Projecting an associated type from a (potentially)
     /// higher-ranked trait reference is more complicated, because of
@@ -403,7 +403,7 @@ fn create_substs_for_ast_path<'tcx>(
     // they were optional (e.g. paths inside expressions).
     let mut type_substs = if param_mode == PathParamMode::Optional &&
                              types_provided.is_empty() {
-        ty_param_defs.iter().map(|p| this.ty_infer(p.default, span)).collect()
+        ty_param_defs.iter().map(|p| this.ty_infer(Some(p.clone()), span)).collect()
     } else {
         types_provided
     };

branches/beta/src/librustc_typeck/check/method/confirm.rs

@@ -315,11 +315,11 @@ impl<'a,'tcx> ConfirmContext<'a,'tcx> {
 
         let method_types = {
             if num_supplied_types == 0 {
-                self.fcx.infcx().type_vars_for_defs(method_types)
+                self.fcx.infcx().type_vars_for_defs(self.span, method_types)
             } else if num_method_types == 0 {
                 span_err!(self.tcx().sess, self.span, E0035,
                     "does not take type parameters");
-                self.fcx.infcx().type_vars_for_defs(method_types)
+                self.fcx.infcx().type_vars_for_defs(self.span, method_types)
             } else if num_supplied_types != num_method_types {
                 span_err!(self.tcx().sess, self.span, E0036,
                     "incorrect number of type parameters given for this method");

branches/beta/src/librustc_typeck/check/method/mod.rs

@@ -176,7 +176,7 @@ pub fn lookup_in_trait_adjusted<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
         }
 
         None => {
-            fcx.inh.infcx.type_vars_for_defs(type_parameter_defs)
+            fcx.inh.infcx.type_vars_for_defs(span, type_parameter_defs)
         }
     };
 

branches/beta/src/librustc_typeck/check/method/probe.rs

@@ -1207,7 +1207,7 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             !method.generics.regions.is_empty_in(subst::FnSpace)
         {
             let method_types =
-                self.infcx().type_vars_for_defs(
+                self.infcx().type_vars_for_defs(self.span,
                     method.generics.types.get_slice(subst::FnSpace));
 
             // In general, during probe we erase regions. See