Handle auto traits & negative impls

We don't pass field types to Chalk yet though, so the auto trait inference won't
be correct.

crates/ra_hir/src/code_model_api.rs

@@ -703,6 +703,10 @@ impl Trait {
         TraitRef::for_trait(db, self)
     }
 
+    pub fn is_auto(self, db: &impl DefDatabase) -> bool {
+        self.trait_data(db).is_auto()
+    }
+
     pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
         let r = self.module(db).resolver(db);
         // add generic params, if present

crates/ra_hir/src/impl_block.rs

@@ -93,6 +93,10 @@ impl ImplBlock {
         db.impls_in_module(self.module).impls[self.impl_id].items().to_vec()
     }
 
+    pub fn is_negative(&self, db: &impl DefDatabase) -> bool {
+        db.impls_in_module(self.module).impls[self.impl_id].negative
+    }
+
     pub(crate) fn resolver(&self, db: &impl DefDatabase) -> Resolver {
         let r = self.module().resolver(db);
         // add generic params, if present
@@ -108,6 +112,7 @@ pub struct ImplData {
     target_trait: Option<TypeRef>,
     target_type: TypeRef,
     items: Vec<ImplItem>,
+    negative: bool,
 }
 
 impl ImplData {
@@ -120,6 +125,7 @@ impl ImplData {
         let target_trait = node.target_trait().map(TypeRef::from_ast);
         let target_type = TypeRef::from_ast_opt(node.target_type());
         let ctx = LocationCtx::new(db, module, file_id);
+        let negative = node.is_negative();
         let items = if let Some(item_list) = node.item_list() {
             item_list
                 .impl_items()
@@ -132,7 +138,7 @@ impl ImplData {
         } else {
             Vec::new()
         };
-        ImplData { target_trait, target_type, items }
+        ImplData { target_trait, target_type, items, negative }
     }
 
     pub fn target_trait(&self) -> Option<&TypeRef> {

crates/ra_hir/src/traits.rs

@@ -11,6 +11,7 @@ use crate::{Function, Const, TypeAlias, Name, DefDatabase, Trait, ids::LocationC
 pub struct TraitData {
     name: Option<Name>,
     items: Vec<TraitItem>,
+    auto: bool,
 }
 
 impl TraitData {
@@ -19,6 +20,7 @@ impl TraitData {
         let name = node.name().map(|n| n.as_name());
         let module = tr.module(db);
         let ctx = LocationCtx::new(db, module, file_id);
+        let auto = node.is_auto();
         let items = if let Some(item_list) = node.item_list() {
             item_list
                 .impl_items()
@@ -31,7 +33,7 @@ impl TraitData {
         } else {
             Vec::new()
         };
-        Arc::new(TraitData { name, items })
+        Arc::new(TraitData { name, items, auto })
     }
 
     pub(crate) fn name(&self) -> &Option<Name> {
@@ -41,6 +43,10 @@ impl TraitData {
     pub(crate) fn items(&self) -> &[TraitItem] {
         &self.items
     }
+
+    pub(crate) fn is_auto(&self) -> bool {
+        self.auto
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]

crates/ra_hir/src/ty/traits/chalk.rs

@@ -12,7 +12,9 @@ use ra_db::salsa::{InternId, InternKey};
 use crate::{
     Trait, HasGenericParams, ImplBlock,
     db::HirDatabase,
-    ty::{TraitRef, Ty, ApplicationTy, TypeCtor, Substs, GenericPredicate}, generics::GenericDef, ty::CallableDef,
+    ty::{TraitRef, Ty, ApplicationTy, TypeCtor, Substs, GenericPredicate, CallableDef},
+    ty::display::HirDisplay,
+    generics::GenericDef,
 };
 use super::ChalkContext;
 
@@ -232,10 +234,10 @@ where
         let bound_vars = Substs::bound_vars(&generic_params);
         let trait_ref = trait_.trait_ref(self.db).subst(&bound_vars).to_chalk(self.db);
         let flags = chalk_rust_ir::TraitFlags {
-            // FIXME set these flags correctly
-            auto: false,
-            marker: false,
+            auto: trait_.is_auto(self.db),
             upstream: trait_.module(self.db).krate(self.db) != Some(self.krate),
+            // FIXME set these flags correctly
+            marker: false,
             fundamental: false,
         };
         let where_clauses = convert_where_clauses(self.db, trait_.into(), &bound_vars);
@@ -329,9 +331,21 @@ where
             chalk_rust_ir::ImplType::External
         };
         let where_clauses = convert_where_clauses(self.db, impl_block.into(), &bound_vars);
+        let negative = impl_block.is_negative(self.db);
+        debug!(
+            "impl {:?}: {}{} where {:?}",
+            impl_id,
+            if negative { "!" } else { "" },
+            trait_ref.display(self.db),
+            where_clauses
+        );
+        let trait_ref = trait_ref.to_chalk(self.db);
         let impl_datum_bound = chalk_rust_ir::ImplDatumBound {
-            // FIXME handle negative impls (impl !Sync for Foo)
-            trait_ref: chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref.to_chalk(self.db)),
+            trait_ref: if negative {
+                chalk_rust_ir::PolarizedTraitRef::Negative(trait_ref)
+            } else {
+                chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref)
+            },
             where_clauses,
             associated_ty_values: Vec::new(), // FIXME add associated type values
             impl_type,

crates/ra_syntax/src/ast/extensions.rs

@@ -170,6 +170,10 @@ impl ast::ImplBlock {
         let second = types.next();
         (first, second)
     }
+
+    pub fn is_negative(&self) -> bool {
+        self.syntax().children_with_tokens().any(|t| t.kind() == EXCL)
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -348,3 +352,9 @@ impl ast::WherePred {
             .find(|it| it.kind() == LIFETIME)
     }
 }
+
+impl ast::TraitDef {
+    pub fn is_auto(&self) -> bool {
+        self.syntax().children_with_tokens().any(|t| t.kind() == AUTO_KW)
+    }
+}