Start of data structure cleanup for trait system. Get rid of CoherenceInfo, make trait_impls less bogus.

7 files changed, 50 insertions, 105 deletions

diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs
index ab42e84e2ac..37c4b183178 100644
--- a/src/librustc/metadata/encoder.rs
+++ b/src/librustc/metadata/encoder.rs
@@ -396,7 +396,7 @@ fn encode_reexported_static_base_methods(ecx: &EncodeContext,
                                          ebml_w: &mut writer::Encoder,
                                          exp: &middle::resolve::Export2)
                                          -> bool {
-    match ecx.tcx.base_impls.find(&exp.def_id) {
+    match ecx.tcx.inherent_impls.find(&exp.def_id) {
         Some(implementations) => {
             for implementations.iter().advance |&base_impl| {
                 for base_impl.methods.iter().advance |&m| {
diff --git a/src/librustc/middle/trans/meth.rs b/src/librustc/middle/trans/meth.rs
index 4ca8057f388..6d0f851d83d 100644
--- a/src/librustc/middle/trans/meth.rs
+++ b/src/librustc/middle/trans/meth.rs
@@ -162,7 +162,7 @@ pub fn trans_method_callee(bcx: block,
             let self_ty = node_id_type(bcx, this.id);
             // <impl_id> is the ID of the implementation of
             // trait <trait_id> for type <self_ty>
-            let impl_id = ty::get_impl_id(tcx, trait_id, self_ty);
+            let impl_id = ty::bogus_get_impl_id_from_ty(tcx, trait_id, self_ty);
             // Get the supertrait's methods
             let supertrait_method_def_ids = ty::trait_method_def_ids(tcx, trait_id);
             // Make sure to fail with a readable error message if
diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 50f331f7e7d..bad29b1c618 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -303,11 +303,13 @@ struct ctxt_ {
     // A method will be in this list if and only if it is a destructor.
     destructors: @mut HashSet<ast::def_id>,
 
-    // Maps a trait onto a mapping from self-ty to impl
-    trait_impls: @mut HashMap<ast::def_id, @mut HashMap<t, @Impl>>,
+    // Maps a trait onto a list of impls of that trait.
+    trait_impls: @mut HashMap<ast::def_id, @mut ~[@Impl]>,
 
-    // Maps a base type to its impl
-    base_impls: @mut HashMap<ast::def_id, @mut ~[@Impl]>,
+    // Maps a def_id of a type to a list of its inherent impls.
+    // Contains implementations of methods that are inherent to a type.
+    // Methods in these implementations don't need to be exported.
+    inherent_impls: @mut HashMap<ast::def_id, @mut ~[@Impl]>,
 
     // Set of used unsafe nodes (functions or blocks). Unsafe nodes not
     // present in this set can be warned about.
@@ -908,7 +910,7 @@ pub fn mk_ctxt(s: session::Session,
         destructor_for_type: @mut HashMap::new(),
         destructors: @mut HashSet::new(),
         trait_impls: @mut HashMap::new(),
-        base_impls:  @mut HashMap::new(),
+        inherent_impls:  @mut HashMap::new(),
         used_unsafe: @mut HashSet::new(),
         used_mut_nodes: @mut HashSet::new(),
      }
@@ -3596,20 +3598,6 @@ pub fn trait_method(cx: ctxt, trait_did: ast::def_id, idx: uint) -> @Method {
 }
 
 
-pub fn add_base_impl(cx: ctxt, base_def_id: def_id, implementation: @Impl) {
-    let implementations;
-    match cx.base_impls.find(&base_def_id) {
-        None => {
-            implementations = @mut ~[];
-            cx.base_impls.insert(base_def_id, implementations);
-        }
-        Some(&existing) => {
-            implementations = existing;
-        }
-    }
-    implementations.push(implementation);
-}
-
 pub fn trait_methods(cx: ctxt, trait_did: ast::def_id) -> @~[@Method] {
     match cx.trait_methods_cache.find(&trait_did) {
         Some(&methods) => methods,
@@ -4375,16 +4363,25 @@ pub fn count_traits_and_supertraits(tcx: ctxt,
     return total;
 }
 
-// Given a trait and a type, returns the impl of that type
-pub fn get_impl_id(tcx: ctxt, trait_id: def_id, self_ty: t) -> def_id {
+// Given a trait and a type, returns the impl of that type.
+// This is broken, of course, by parametric impls. This used to use
+// a table specifically for this mapping, but I removed that table.
+// This is only used when calling a supertrait method from a default method,
+// and should go away once I fix how that works. -sully
+pub fn bogus_get_impl_id_from_ty(tcx: ctxt,
+                                 trait_id: def_id, self_ty: t) -> def_id {
     match tcx.trait_impls.find(&trait_id) {
-        Some(ty_to_impl) => match ty_to_impl.find(&self_ty) {
-            Some(the_impl) => the_impl.did,
-            None => // try autoderef!
-                match deref(tcx, self_ty, false) {
-                    Some(some_ty) => get_impl_id(tcx, trait_id, some_ty.ty),
-                    None => tcx.sess.bug("get_impl_id: no impl of trait for \
-                                          this type")
+        Some(ty_to_impl) => {
+            for ty_to_impl.iter().advance |imp| {
+                let impl_ty = tcx.tcache.get_copy(&imp.did);
+                if impl_ty.ty == self_ty { return imp.did; }
+            }
+            // try autoderef!
+            match deref(tcx, self_ty, false) {
+                Some(some_ty) =>
+                  bogus_get_impl_id_from_ty(tcx, trait_id, some_ty.ty),
+                None => tcx.sess.bug("get_impl_id: no impl of trait for \
+                                      this type")
             }
         },
         None => tcx.sess.bug("get_impl_id: trait isn't in trait_impls")
diff --git a/src/librustc/middle/typeck/check/method.rs b/src/librustc/middle/typeck/check/method.rs
index d2a11953af0..06ce6420123 100644
--- a/src/librustc/middle/typeck/check/method.rs
+++ b/src/librustc/middle/typeck/check/method.rs
@@ -330,8 +330,7 @@ impl<'self> LookupContext<'self> {
         for opt_applicable_traits.iter().advance |applicable_traits| {
             for applicable_traits.iter().advance |trait_did| {
                 // Look for explicit implementations.
-                let opt_impl_infos =
-                    self.fcx.ccx.coherence_info.extension_methods.find(trait_did);
+                let opt_impl_infos = self.tcx().trait_impls.find(trait_did);
                 for opt_impl_infos.iter().advance |impl_infos| {
                     for impl_infos.iter().advance |impl_info| {
                         self.push_candidates_from_impl(
@@ -517,8 +516,7 @@ impl<'self> LookupContext<'self> {
     }
 
     pub fn push_inherent_impl_candidates_for_type(&self, did: def_id) {
-        let opt_impl_infos =
-            self.fcx.ccx.coherence_info.inherent_methods.find(&did);
+        let opt_impl_infos = self.tcx().inherent_impls.find(&did);
         for opt_impl_infos.iter().advance |impl_infos| {
             for impl_infos.iter().advance |impl_info| {
                 self.push_candidates_from_impl(
diff --git a/src/librustc/middle/typeck/check/vtable.rs b/src/librustc/middle/typeck/check/vtable.rs
index d9036c72db6..6af0be48e47 100644
--- a/src/librustc/middle/typeck/check/vtable.rs
+++ b/src/librustc/middle/typeck/check/vtable.rs
@@ -260,7 +260,7 @@ fn lookup_vtable(vcx: &VtableContext,
 
             let mut impls_seen = HashSet::new();
 
-            match vcx.ccx.coherence_info.extension_methods.find(&trait_ref.def_id) {
+            match tcx.trait_impls.find(&trait_ref.def_id) {
                 None => {
                     // Nothing found. Continue.
                 }
diff --git a/src/librustc/middle/typeck/coherence.rs b/src/librustc/middle/typeck/coherence.rs
index 3a4154d7c50..b6555625f65 100644
--- a/src/librustc/middle/typeck/coherence.rs
+++ b/src/librustc/middle/typeck/coherence.rs
@@ -159,23 +159,6 @@ pub fn method_to_MethodInfo(ast_method: @method) -> @MethodInfo {
     }
 }
 
-pub struct CoherenceInfo {
-    // Contains implementations of methods that are inherent to a type.
-    // Methods in these implementations don't need to be exported.
-    inherent_methods: @mut HashMap<def_id, @mut ~[@Impl]>,
-
-    // Contains implementations of methods associated with a trait. For these,
-    // the associated trait must be imported at the call site.
-    extension_methods: @mut HashMap<def_id, @mut ~[@Impl]>,
-}
-
-pub fn CoherenceInfo() -> CoherenceInfo {
-    CoherenceInfo {
-        inherent_methods: @mut HashMap::new(),
-        extension_methods: @mut HashMap::new(),
-    }
-}
-
 pub fn CoherenceChecker(crate_context: @mut CrateCtxt) -> CoherenceChecker {
     CoherenceChecker {
         crate_context: crate_context,
@@ -287,7 +270,7 @@ impl CoherenceChecker {
                 implementation_opt = Some(implementation);
             }
 
-            self.add_trait_method(trait_ref.def_id, implementation_opt.get());
+            self.add_trait_impl(trait_ref.def_id, implementation_opt.get());
         }
 
         // Add the implementation to the mapping from implementation to base
@@ -313,8 +296,7 @@ impl CoherenceChecker {
                         }
                     }
 
-                    self.add_inherent_method(base_type_def_id,
-                                             implementation);
+                    self.add_inherent_impl(base_type_def_id, implementation);
                 }
 
                 self.base_type_def_ids.insert(local_def(item.id),
@@ -418,16 +400,15 @@ impl CoherenceChecker {
         }
     }
 
-    pub fn add_inherent_method(&self,
-                               base_def_id: def_id,
-                               implementation: @Impl) {
+    pub fn add_inherent_impl(&self,
+                             base_def_id: def_id,
+                             implementation: @Impl) {
+        let tcx = self.crate_context.tcx;
         let implementation_list;
-        match self.crate_context.coherence_info.inherent_methods
-                  .find(&base_def_id) {
+        match tcx.inherent_impls.find(&base_def_id) {
             None => {
                 implementation_list = @mut ~[];
-                self.crate_context.coherence_info.inherent_methods
-                    .insert(base_def_id, implementation_list);
+                tcx.inherent_impls.insert(base_def_id, implementation_list);
             }
             Some(&existing_implementation_list) => {
                 implementation_list = existing_implementation_list;
@@ -435,18 +416,17 @@ impl CoherenceChecker {
         }
 
         implementation_list.push(implementation);
-
-        ty::add_base_impl(self.crate_context.tcx, base_def_id, implementation);
     }
 
-    pub fn add_trait_method(&self, trait_id: def_id, implementation: @Impl) {
+    pub fn add_trait_impl(&self,
+                          base_def_id: def_id,
+                          implementation: @Impl) {
+        let tcx = self.crate_context.tcx;
         let implementation_list;
-        match self.crate_context.coherence_info.extension_methods
-                  .find(&trait_id) {
+        match tcx.trait_impls.find(&base_def_id) {
             None => {
                 implementation_list = @mut ~[];
-                self.crate_context.coherence_info.extension_methods
-                    .insert(trait_id, implementation_list);
+                tcx.trait_impls.insert(base_def_id, implementation_list);
             }
             Some(&existing_implementation_list) => {
                 implementation_list = existing_implementation_list;
@@ -457,8 +437,7 @@ impl CoherenceChecker {
     }
 
     pub fn check_implementation_coherence(&self) {
-        let coherence_info = &self.crate_context.coherence_info;
-        for coherence_info.extension_methods.each_key |&trait_id| {
+        for self.crate_context.tcx.trait_impls.each_key |&trait_id| {
             self.check_implementation_coherence_of(trait_id);
         }
     }
@@ -472,8 +451,6 @@ impl CoherenceChecker {
 
             // "We have an impl of trait <trait_def_id> for type <polytype_a>,
             // and that impl is <implementation_a>"
-            self.add_impl_for_trait(trait_def_id, polytype_a.ty,
-                                    implementation_a);
             do self.iter_impls_of_trait(trait_def_id) |b| {
                 let implementation_b = b;
 
@@ -494,32 +471,8 @@ impl CoherenceChecker {
         }
     }
 
-    // Adds an impl of trait trait_t for self type self_t; that impl
-    // is the_impl
-    pub fn add_impl_for_trait(&self,
-                              trait_t: def_id,
-                              self_t: t,
-                              the_impl: @Impl) {
-        debug!("Adding impl %? of %? for %s",
-               the_impl.did, trait_t,
-               ty_to_str(self.crate_context.tcx, self_t));
-        match self.crate_context.tcx.trait_impls.find(&trait_t) {
-            None => {
-                let m = @mut HashMap::new();
-                m.insert(self_t, the_impl);
-                self.crate_context.tcx.trait_impls.insert(trait_t, m);
-            }
-            Some(&m) => {
-                m.insert(self_t, the_impl);
-            }
-        }
-    }
-
     pub fn iter_impls_of_trait(&self, trait_def_id: def_id, f: &fn(@Impl)) {
-        let coherence_info = &self.crate_context.coherence_info;
-        let extension_methods = &*coherence_info.extension_methods;
-
-        match extension_methods.find(&trait_def_id) {
+        match self.crate_context.tcx.trait_impls.find(&trait_def_id) {
             Some(impls) => {
                 for impls.iter().advance |&im| {
                     f(im);
@@ -874,7 +827,7 @@ impl CoherenceChecker {
                 ..*implementation
             };
 
-            self.add_trait_method(trait_ref.def_id, implementation);
+            self.add_trait_impl(trait_ref.def_id, implementation);
         }
 
         // Add the implementation to the mapping from implementation to base
@@ -887,8 +840,8 @@ impl CoherenceChecker {
                 // inherent methods apply to `impl Type` but not
                 // `impl Trait for Type`:
                 if associated_traits.is_none() {
-                    self.add_inherent_method(base_type_def_id,
-                                             implementation);
+                    self.add_inherent_impl(base_type_def_id,
+                                           implementation);
                 }
 
                 self.base_type_def_ids.insert(implementation.did,
@@ -922,12 +875,11 @@ impl CoherenceChecker {
     //
 
     pub fn populate_destructor_table(&self) {
-        let coherence_info = &self.crate_context.coherence_info;
         let tcx = self.crate_context.tcx;
         let drop_trait = match tcx.lang_items.drop_trait() {
             Some(id) => id, None => { return }
         };
-        let impls_opt = coherence_info.extension_methods.find(&drop_trait);
+        let impls_opt = tcx.trait_impls.find(&drop_trait);
 
         let impls;
         match impls_opt {
diff --git a/src/librustc/middle/typeck/mod.rs b/src/librustc/middle/typeck/mod.rs
index 5f68f439eba..bfbebd0a52e 100644
--- a/src/librustc/middle/typeck/mod.rs
+++ b/src/librustc/middle/typeck/mod.rs
@@ -192,7 +192,6 @@ pub struct CrateCtxt {
     trait_map: resolve::TraitMap,
     method_map: method_map,
     vtable_map: vtable_map,
-    coherence_info: coherence::CoherenceInfo,
     tcx: ty::ctxt
 }
 
@@ -415,7 +414,6 @@ pub fn check_crate(tcx: ty::ctxt,
         trait_map: trait_map,
         method_map: @mut HashMap::new(),
         vtable_map: @mut HashMap::new(),
-        coherence_info: coherence::CoherenceInfo(),
         tcx: tcx
     };