13 files changed, 358 insertions, 253 deletions

diff --git a/crates/ra_cli/Cargo.toml b/crates/ra_cli/Cargo.toml
index 301145b5d..b10873cd8 100644
--- a/crates/ra_cli/Cargo.toml
+++ b/crates/ra_cli/Cargo.toml
@@ -16,4 +16,7 @@ ra_ide_api = { path = "../ra_ide_api" }
 ra_batch = { path = "../ra_batch" }
 ra_hir = { path = "../ra_hir" }
 ra_db = { path = "../ra_db" }
-ra_prof = { path = "../ra_prof" }
+
+[dependencies.ra_prof]
+path = "../ra_prof"
+# features = [ "cpuprofiler" ]
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index d8832a9de..8f4de1c85 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -20,13 +20,41 @@ use crate::{
     lang_item::{LangItems, LangItemTarget}, type_alias::TypeAliasData,
 };
 
-// This database has access to source code, so queries here are not really
-// incremental.
-#[salsa::query_group(AstDatabaseStorage)]
-pub trait AstDatabase: SourceDatabase {
+/// We store all interned things in the single QueryGroup.
+///
+/// This is done mainly to allow both "volatile" `AstDatabase` and "stable"
+/// `DefDatabase` to access macros, without adding hard dependencies between the
+/// two.
+#[salsa::query_group(InternDatabaseStorage)]
+pub trait InternDatabase: SourceDatabase {
     #[salsa::interned]
     fn intern_macro(&self, macro_call: MacroCallLoc) -> ids::MacroCallId;
+    #[salsa::interned]
+    fn intern_function(&self, loc: ids::ItemLoc<ast::FnDef>) -> ids::FunctionId;
+    #[salsa::interned]
+    fn intern_struct(&self, loc: ids::ItemLoc<ast::StructDef>) -> ids::StructId;
+    #[salsa::interned]
+    fn intern_enum(&self, loc: ids::ItemLoc<ast::EnumDef>) -> ids::EnumId;
+    #[salsa::interned]
+    fn intern_const(&self, loc: ids::ItemLoc<ast::ConstDef>) -> ids::ConstId;
+    #[salsa::interned]
+    fn intern_static(&self, loc: ids::ItemLoc<ast::StaticDef>) -> ids::StaticId;
+    #[salsa::interned]
+    fn intern_trait(&self, loc: ids::ItemLoc<ast::TraitDef>) -> ids::TraitId;
+    #[salsa::interned]
+    fn intern_type_alias(&self, loc: ids::ItemLoc<ast::TypeAliasDef>) -> ids::TypeAliasId;
 
+    // Interned IDs for Chalk integration
+    #[salsa::interned]
+    fn intern_type_ctor(&self, type_ctor: TypeCtor) -> ids::TypeCtorId;
+    #[salsa::interned]
+    fn intern_impl_block(&self, impl_block: ImplBlock) -> ids::GlobalImplId;
+}
+
+/// This database has access to source code, so queries here are not really
+/// incremental.
+#[salsa::query_group(AstDatabaseStorage)]
+pub trait AstDatabase: InternDatabase {
     #[salsa::invoke(crate::source_id::AstIdMap::ast_id_map_query)]
     fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
     #[salsa::transparent]
@@ -40,7 +68,6 @@ pub trait AstDatabase: SourceDatabase {
 
     #[salsa::invoke(crate::ids::macro_def_query)]
     fn macro_def(&self, macro_id: MacroDefId) -> Option<Arc<mbe::MacroRules>>;
-
     #[salsa::invoke(crate::ids::macro_arg_query)]
     fn macro_arg(&self, macro_call: ids::MacroCallId) -> Option<Arc<tt::Subtree>>;
 
@@ -51,28 +78,7 @@ pub trait AstDatabase: SourceDatabase {
 // This database uses `AstDatabase` internally,
 #[salsa::query_group(DefDatabaseStorage)]
 #[salsa::requires(AstDatabase)]
-pub trait DefDatabase: SourceDatabase {
-    #[salsa::interned]
-    fn intern_function(&self, loc: ids::ItemLoc<ast::FnDef>) -> ids::FunctionId;
-    #[salsa::interned]
-    fn intern_struct(&self, loc: ids::ItemLoc<ast::StructDef>) -> ids::StructId;
-    #[salsa::interned]
-    fn intern_enum(&self, loc: ids::ItemLoc<ast::EnumDef>) -> ids::EnumId;
-    #[salsa::interned]
-    fn intern_const(&self, loc: ids::ItemLoc<ast::ConstDef>) -> ids::ConstId;
-    #[salsa::interned]
-    fn intern_static(&self, loc: ids::ItemLoc<ast::StaticDef>) -> ids::StaticId;
-    #[salsa::interned]
-    fn intern_trait(&self, loc: ids::ItemLoc<ast::TraitDef>) -> ids::TraitId;
-    #[salsa::interned]
-    fn intern_type_alias(&self, loc: ids::ItemLoc<ast::TypeAliasDef>) -> ids::TypeAliasId;
-
-    // Interned IDs for Chalk integration
-    #[salsa::interned]
-    fn intern_type_ctor(&self, type_ctor: TypeCtor) -> ids::TypeCtorId;
-    #[salsa::interned]
-    fn intern_impl_block(&self, impl_block: ImplBlock) -> ids::GlobalImplId;
-
+pub trait DefDatabase: InternDatabase {
     #[salsa::invoke(crate::adt::StructData::struct_data_query)]
     fn struct_data(&self, s: Struct) -> Arc<StructData>;
 
@@ -181,6 +187,26 @@ pub trait HirDatabase: DefDatabase + AstDatabase {
     #[salsa::volatile]
     fn solver(&self, krate: Crate) -> Arc<Mutex<crate::ty::traits::Solver>>;
 
+    #[salsa::invoke(crate::ty::traits::chalk::associated_ty_data_query)]
+    fn associated_ty_data(&self, id: chalk_ir::TypeId) -> Arc<chalk_rust_ir::AssociatedTyDatum>;
+
+    #[salsa::invoke(crate::ty::traits::chalk::trait_datum_query)]
+    fn trait_datum(
+        &self,
+        krate: Crate,
+        trait_id: chalk_ir::TraitId,
+    ) -> Arc<chalk_rust_ir::TraitDatum>;
+
+    #[salsa::invoke(crate::ty::traits::chalk::struct_datum_query)]
+    fn struct_datum(
+        &self,
+        krate: Crate,
+        struct_id: chalk_ir::StructId,
+    ) -> Arc<chalk_rust_ir::StructDatum>;
+
+    #[salsa::invoke(crate::ty::traits::chalk::impl_datum_query)]
+    fn impl_datum(&self, krate: Crate, impl_id: chalk_ir::ImplId) -> Arc<chalk_rust_ir::ImplDatum>;
+
     #[salsa::invoke(crate::ty::traits::implements_query)]
     fn implements(
         &self,
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 033af1632..b7215ac03 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -9,7 +9,7 @@ use ra_prof::profile;
 use mbe::MacroRules;
 
 use crate::{
-    Module, DefDatabase, AstId, FileAstId, AstDatabase, Source,
+    Module, DefDatabase, AstId, FileAstId, AstDatabase, Source, InternDatabase,
 };
 
 /// hir makes heavy use of ids: integer (u32) handlers to various things. You
@@ -37,7 +37,7 @@ pub struct HirFileId(HirFileIdRepr);
 impl HirFileId {
     /// For macro-expansion files, returns the file original source file the
     /// expansion originated from.
-    pub fn original_file(self, db: &impl AstDatabase) -> FileId {
+    pub fn original_file(self, db: &impl InternDatabase) -> FileId {
         match self.0 {
             HirFileIdRepr::File(file_id) => file_id,
             HirFileIdRepr::Macro(macro_file) => {
@@ -187,7 +187,7 @@ pub struct MacroCallLoc {
 }
 
 impl MacroCallId {
-    pub(crate) fn loc(self, db: &impl AstDatabase) -> MacroCallLoc {
+    pub(crate) fn loc(self, db: &impl InternDatabase) -> MacroCallLoc {
         db.lookup_intern_macro(self)
     }
 
@@ -198,7 +198,7 @@ impl MacroCallId {
 }
 
 impl MacroCallLoc {
-    pub(crate) fn id(self, db: &impl AstDatabase) -> MacroCallId {
+    pub(crate) fn id(self, db: &impl InternDatabase) -> MacroCallId {
         db.intern_macro(self)
     }
 }
@@ -235,10 +235,13 @@ pub(crate) struct LocationCtx<DB> {
     file_id: HirFileId,
 }
 
-impl<'a, DB: DefDatabase + AstDatabase> LocationCtx<&'a DB> {
+impl<'a, DB: DefDatabase> LocationCtx<&'a DB> {
     pub(crate) fn new(db: &'a DB, module: Module, file_id: HirFileId) -> LocationCtx<&'a DB> {
         LocationCtx { db, module, file_id }
     }
+}
+
+impl<'a, DB: DefDatabase + AstDatabase> LocationCtx<&'a DB> {
     pub(crate) fn to_def<N, DEF>(self, ast: &N) -> DEF
     where
         N: AstNode,
@@ -257,10 +260,7 @@ pub(crate) trait AstItemDef<N: AstNode>: salsa::InternKey + Clone {
         let item_id = items.ast_id(ast);
         Self::from_ast_id(ctx, item_id)
     }
-    fn from_ast_id(
-        ctx: LocationCtx<&(impl AstDatabase + DefDatabase)>,
-        ast_id: FileAstId<N>,
-    ) -> Self {
+    fn from_ast_id(ctx: LocationCtx<&impl DefDatabase>, ast_id: FileAstId<N>) -> Self {
         let loc = ItemLoc { module: ctx.module, ast_id: ast_id.with_file_id(ctx.file_id) };
         Self::intern(ctx.db, loc)
     }
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index f07a36926..5afd846f5 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -47,7 +47,7 @@ mod code_model;
 mod marks;
 
 use crate::{
-    db::{AstDatabase, DefDatabase, HirDatabase},
+    db::{InternDatabase, AstDatabase, DefDatabase, HirDatabase},
     name::{AsName, KnownName},
     source_id::{FileAstId, AstId},
     resolve::Resolver,
diff --git a/crates/ra_hir/src/mock.rs b/crates/ra_hir/src/mock.rs
index 5d38ac76c..c57dfbf01 100644
--- a/crates/ra_hir/src/mock.rs
+++ b/crates/ra_hir/src/mock.rs
@@ -15,6 +15,7 @@ pub const WORKSPACE: SourceRootId = SourceRootId(0);
 
 #[salsa::database(
     ra_db::SourceDatabaseStorage,
+    db::InternDatabaseStorage,
     db::AstDatabaseStorage,
     db::DefDatabaseStorage,
     db::HirDatabaseStorage
diff --git a/crates/ra_hir/src/nameres.rs b/crates/ra_hir/src/nameres.rs
index 3532faf01..f4ca454e4 100644
--- a/crates/ra_hir/src/nameres.rs
+++ b/crates/ra_hir/src/nameres.rs
@@ -231,7 +231,9 @@ fn or(left: ItemOrMacro, right: ItemOrMacro) -> ItemOrMacro {
 
 impl CrateDefMap {
     pub(crate) fn crate_def_map_query(
-        db: &(impl DefDatabase + AstDatabase),
+        // Note that this doesn't have `+ AstDatabase`!
+        // This gurantess that `CrateDefMap` is stable across reparses.
+        db: &impl DefDatabase,
         krate: Crate,
     ) -> Arc<CrateDefMap> {
         let _p = profile("crate_def_map_query");
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index b74dc33b1..ef4d1ed70 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -7,7 +7,7 @@ use ra_syntax::ast;
 
 use crate::{
     Function, Module, Struct, Union, Enum, Const, Static, Trait, TypeAlias, MacroDef,
-    DefDatabase, HirFileId, Name, Path, AstDatabase,
+    DefDatabase, HirFileId, Name, Path,
     KnownName, AstId,
     nameres::{
         Resolution, PerNs, ModuleDef, ReachedFixedPoint, ResolveMode,
@@ -19,10 +19,7 @@ use crate::{
     either::Either,
 };
 
-pub(super) fn collect_defs(
-    db: &(impl DefDatabase + AstDatabase),
-    mut def_map: CrateDefMap,
-) -> CrateDefMap {
+pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
     // populate external prelude
     for dep in def_map.krate.dependencies(db) {
         log::debug!("crate dep {:?} -> {:?}", dep.name, dep.krate);
@@ -95,7 +92,7 @@ struct DefCollector<DB> {
 
 impl<'a, DB> DefCollector<&'a DB>
 where
-    DB: DefDatabase + AstDatabase,
+    DB: DefDatabase,
 {
     fn collect(&mut self) {
         let crate_graph = self.db.crate_graph();
@@ -465,7 +462,7 @@ where
             ModCollector { def_collector: &mut *self, file_id, module_id, raw_items: &raw_items }
                 .collect(raw_items.items());
         } else {
-            log::error!("Too deep macro expansion: {}", macro_call_id.debug_dump(self.db));
+            log::error!("Too deep macro expansion: {:?}", macro_call_id);
             self.def_map.poison_macros.insert(macro_def_id);
         }
 
@@ -487,7 +484,7 @@ struct ModCollector<'a, D> {
 
 impl<DB> ModCollector<'_, &'_ mut DefCollector<&'_ DB>>
 where
-    DB: DefDatabase + AstDatabase,
+    DB: DefDatabase,
 {
     fn collect(&mut self, items: &[raw::RawItem]) {
         for item in items {
@@ -632,7 +629,7 @@ fn is_macro_rules(path: &Path) -> bool {
 }
 
 fn resolve_submodule(
-    db: &(impl DefDatabase + AstDatabase),
+    db: &impl DefDatabase,
     file_id: HirFileId,
     name: &Name,
     is_root: bool,
@@ -675,7 +672,7 @@ mod tests {
     use rustc_hash::FxHashSet;
 
     fn do_collect_defs(
-        db: &(impl DefDatabase + AstDatabase),
+        db: &impl DefDatabase,
         def_map: CrateDefMap,
         monitor: MacroStackMonitor,
     ) -> CrateDefMap {
diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index 9a6349d4b..69c03a36c 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -12,7 +12,7 @@ use super::{TraitRef, Ty, Canonical, ProjectionTy};
 
 use self::chalk::{ToChalk, from_chalk};
 
-mod chalk;
+pub(crate) mod chalk;
 
 pub(crate) type Solver = chalk_solve::Solver;
 
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 5105588ee..4ceb8b70b 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -10,7 +10,7 @@ use test_utils::tested_by;
 use ra_db::salsa::{InternId, InternKey};
 
 use crate::{
-    Trait, HasGenericParams, ImplBlock,
+    Trait, HasGenericParams, ImplBlock, Crate,
     db::HirDatabase,
     ty::{TraitRef, Ty, ApplicationTy, TypeCtor, Substs, GenericPredicate, CallableDef, ProjectionTy},
     ty::display::HirDisplay,
@@ -256,204 +256,16 @@ where
     DB: HirDatabase,
 {
     fn associated_ty_data(&self, id: TypeId) -> Arc<AssociatedTyDatum> {
-        debug!("associated_ty_data {:?}", id);
-        let type_alias: TypeAlias = from_chalk(self.db, id);
-        let trait_ = match type_alias.container(self.db) {
-            Some(crate::Container::Trait(t)) => t,
-            _ => panic!("associated type not in trait"),
-        };
-        let generic_params = type_alias.generic_params(self.db);
-        let parameter_kinds = generic_params
-            .params_including_parent()
-            .into_iter()
-            .map(|p| chalk_ir::ParameterKind::Ty(lalrpop_intern::intern(&p.name.to_string())))
-            .collect();
-        let datum = AssociatedTyDatum {
-            trait_id: trait_.to_chalk(self.db),
-            id,
-            name: lalrpop_intern::intern(&type_alias.name(self.db).to_string()),
-            parameter_kinds,
-            // FIXME add bounds and where clauses
-            bounds: vec![],
-            where_clauses: vec![],
-        };
-        Arc::new(datum)
+        self.db.associated_ty_data(id)
     }
     fn trait_datum(&self, trait_id: chalk_ir::TraitId) -> Arc<TraitDatum> {
-        debug!("trait_datum {:?}", trait_id);
-        if trait_id == UNKNOWN_TRAIT {
-            let trait_datum_bound = chalk_rust_ir::TraitDatumBound {
-                trait_ref: chalk_ir::TraitRef {
-                    trait_id: UNKNOWN_TRAIT,
-                    parameters: vec![chalk_ir::Ty::BoundVar(0).cast()],
-                },
-                associated_ty_ids: Vec::new(),
-                where_clauses: Vec::new(),
-                flags: chalk_rust_ir::TraitFlags {
-                    auto: false,
-                    marker: false,
-                    upstream: true,
-                    fundamental: false,
-                },
-            };
-            return Arc::new(TraitDatum { binders: make_binders(trait_datum_bound, 1) });
-        }
-        let trait_: Trait = from_chalk(self.db, trait_id);
-        debug!("trait {:?} = {:?}", trait_id, trait_.name(self.db));
-        let generic_params = trait_.generic_params(self.db);
-        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 {
-            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);
-        let associated_ty_ids = trait_
-            .items(self.db)
-            .into_iter()
-            .filter_map(|trait_item| match trait_item {
-                crate::traits::TraitItem::TypeAlias(type_alias) => Some(type_alias),
-                _ => None,
-            })
-            .map(|type_alias| type_alias.to_chalk(self.db))
-            .collect();
-        let trait_datum_bound =
-            chalk_rust_ir::TraitDatumBound { trait_ref, where_clauses, flags, associated_ty_ids };
-        let trait_datum = TraitDatum { binders: make_binders(trait_datum_bound, bound_vars.len()) };
-        Arc::new(trait_datum)
+        self.db.trait_datum(self.krate, trait_id)
     }
     fn struct_datum(&self, struct_id: chalk_ir::StructId) -> Arc<StructDatum> {
-        debug!("struct_datum {:?}", struct_id);
-        let type_ctor = from_chalk(self.db, struct_id);
-        debug!("struct {:?} = {:?}", struct_id, type_ctor);
-        // FIXME might be nicer if we can create a fake GenericParams for the TypeCtor
-        // FIXME extract this to a method on Ty
-        let (num_params, where_clauses, upstream) = match type_ctor {
-            TypeCtor::Bool
-            | TypeCtor::Char
-            | TypeCtor::Int(_)
-            | TypeCtor::Float(_)
-            | TypeCtor::Never
-            | TypeCtor::Str => (0, vec![], true),
-            TypeCtor::Slice | TypeCtor::Array | TypeCtor::RawPtr(_) | TypeCtor::Ref(_) => {
-                (1, vec![], true)
-            }
-            TypeCtor::FnPtr { num_args } => (num_args as usize + 1, vec![], true),
-            TypeCtor::Tuple { cardinality } => (cardinality as usize, vec![], true),
-            TypeCtor::FnDef(callable) => {
-                tested_by!(trait_resolution_on_fn_type);
-                let krate = match callable {
-                    CallableDef::Function(f) => f.module(self.db).krate(self.db),
-                    CallableDef::Struct(s) => s.module(self.db).krate(self.db),
-                    CallableDef::EnumVariant(v) => {
-                        v.parent_enum(self.db).module(self.db).krate(self.db)
-                    }
-                };
-                let generic_def: GenericDef = match callable {
-                    CallableDef::Function(f) => f.into(),
-                    CallableDef::Struct(s) => s.into(),
-                    CallableDef::EnumVariant(v) => v.parent_enum(self.db).into(),
-                };
-                let generic_params = generic_def.generic_params(self.db);
-                let bound_vars = Substs::bound_vars(&generic_params);
-                let where_clauses = convert_where_clauses(self.db, generic_def, &bound_vars);
-                (
-                    generic_params.count_params_including_parent(),
-                    where_clauses,
-                    krate != Some(self.krate),
-                )
-            }
-            TypeCtor::Adt(adt) => {
-                let generic_params = adt.generic_params(self.db);
-                let bound_vars = Substs::bound_vars(&generic_params);
-                let where_clauses = convert_where_clauses(self.db, adt.into(), &bound_vars);
-                (
-                    generic_params.count_params_including_parent(),
-                    where_clauses,
-                    adt.krate(self.db) != Some(self.krate),
-                )
-            }
-        };
-        let flags = chalk_rust_ir::StructFlags {
-            upstream,
-            // FIXME set fundamental flag correctly
-            fundamental: false,
-        };
-        let self_ty = chalk_ir::ApplicationTy {
-            name: TypeName::TypeKindId(type_ctor.to_chalk(self.db).into()),
-            parameters: (0..num_params).map(|i| chalk_ir::Ty::BoundVar(i).cast()).collect(),
-        };
-        let struct_datum_bound = chalk_rust_ir::StructDatumBound {
-            self_ty,
-            fields: Vec::new(), // FIXME add fields (only relevant for auto traits)
-            where_clauses,
-            flags,
-        };
-        let struct_datum = StructDatum { binders: make_binders(struct_datum_bound, num_params) };
-        Arc::new(struct_datum)
+        self.db.struct_datum(self.krate, struct_id)
     }
     fn impl_datum(&self, impl_id: ImplId) -> Arc<ImplDatum> {
-        debug!("impl_datum {:?}", impl_id);
-        let impl_block: ImplBlock = from_chalk(self.db, impl_id);
-        let generic_params = impl_block.generic_params(self.db);
-        let bound_vars = Substs::bound_vars(&generic_params);
-        let trait_ref = impl_block
-            .target_trait_ref(self.db)
-            .expect("FIXME handle unresolved impl block trait ref")
-            .subst(&bound_vars);
-        let impl_type = if impl_block.module().krate(self.db) == Some(self.krate) {
-            chalk_rust_ir::ImplType::Local
-        } else {
-            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_ = trait_ref.trait_;
-        let trait_ref = trait_ref.to_chalk(self.db);
-        let associated_ty_values = impl_block
-            .items(self.db)
-            .into_iter()
-            .filter_map(|item| match item {
-                ImplItem::TypeAlias(t) => Some(t),
-                _ => None,
-            })
-            .filter_map(|t| {
-                let assoc_ty = trait_.associated_type_by_name(self.db, t.name(self.db))?;
-                let ty = self.db.type_for_def(t.into(), crate::Namespace::Types).subst(&bound_vars);
-                Some(chalk_rust_ir::AssociatedTyValue {
-                    impl_id,
-                    associated_ty_id: assoc_ty.to_chalk(self.db),
-                    value: chalk_ir::Binders {
-                        value: chalk_rust_ir::AssociatedTyValueBound { ty: ty.to_chalk(self.db) },
-                        binders: vec![], // we don't support GATs yet
-                    },
-                })
-            })
-            .collect();
-
-        let impl_datum_bound = chalk_rust_ir::ImplDatumBound {
-            trait_ref: if negative {
-                chalk_rust_ir::PolarizedTraitRef::Negative(trait_ref)
-            } else {
-                chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref)
-            },
-            where_clauses,
-            associated_ty_values,
-            impl_type,
-        };
-        debug!("impl_datum: {:?}", impl_datum_bound);
-        let impl_datum = ImplDatum { binders: make_binders(impl_datum_bound, bound_vars.len()) };
-        Arc::new(impl_datum)
+        self.db.impl_datum(self.krate, impl_id)
     }
     fn impls_for_trait(&self, trait_id: chalk_ir::TraitId) -> Vec<ImplId> {
         debug!("impls_for_trait {:?}", trait_id);
@@ -503,6 +315,220 @@ where
     }
 }
 
+pub(crate) fn associated_ty_data_query(
+    db: &impl HirDatabase,
+    id: TypeId,
+) -> Arc<AssociatedTyDatum> {
+    debug!("associated_ty_data {:?}", id);
+    let type_alias: TypeAlias = from_chalk(db, id);
+    let trait_ = match type_alias.container(db) {
+        Some(crate::Container::Trait(t)) => t,
+        _ => panic!("associated type not in trait"),
+    };
+    let generic_params = type_alias.generic_params(db);
+    let parameter_kinds = generic_params
+        .params_including_parent()
+        .into_iter()
+        .map(|p| chalk_ir::ParameterKind::Ty(lalrpop_intern::intern(&p.name.to_string())))
+        .collect();
+    let datum = AssociatedTyDatum {
+        trait_id: trait_.to_chalk(db),
+        id,
+        name: lalrpop_intern::intern(&type_alias.name(db).to_string()),
+        parameter_kinds,
+        // FIXME add bounds and where clauses
+        bounds: vec![],
+        where_clauses: vec![],
+    };
+    Arc::new(datum)
+}
+
+pub(crate) fn trait_datum_query(
+    db: &impl HirDatabase,
+    krate: Crate,
+    trait_id: chalk_ir::TraitId,
+) -> Arc<TraitDatum> {
+    debug!("trait_datum {:?}", trait_id);
+    if trait_id == UNKNOWN_TRAIT {
+        let trait_datum_bound = chalk_rust_ir::TraitDatumBound {
+            trait_ref: chalk_ir::TraitRef {
+                trait_id: UNKNOWN_TRAIT,
+                parameters: vec![chalk_ir::Ty::BoundVar(0).cast()],
+            },
+            associated_ty_ids: Vec::new(),
+            where_clauses: Vec::new(),
+            flags: chalk_rust_ir::TraitFlags {
+                auto: false,
+                marker: false,
+                upstream: true,
+                fundamental: false,
+            },
+        };
+        return Arc::new(TraitDatum { binders: make_binders(trait_datum_bound, 1) });
+    }
+    let trait_: Trait = from_chalk(db, trait_id);
+    debug!("trait {:?} = {:?}", trait_id, trait_.name(db));
+    let generic_params = trait_.generic_params(db);
+    let bound_vars = Substs::bound_vars(&generic_params);
+    let trait_ref = trait_.trait_ref(db).subst(&bound_vars).to_chalk(db);
+    let flags = chalk_rust_ir::TraitFlags {
+        auto: trait_.is_auto(db),
+        upstream: trait_.module(db).krate(db) != Some(krate),
+        // FIXME set these flags correctly
+        marker: false,
+        fundamental: false,
+    };
+    let where_clauses = convert_where_clauses(db, trait_.into(), &bound_vars);
+    let associated_ty_ids = trait_
+        .items(db)
+        .into_iter()
+        .filter_map(|trait_item| match trait_item {
+            crate::traits::TraitItem::TypeAlias(type_alias) => Some(type_alias),
+            _ => None,
+        })
+        .map(|type_alias| type_alias.to_chalk(db))
+        .collect();
+    let trait_datum_bound =
+        chalk_rust_ir::TraitDatumBound { trait_ref, where_clauses, flags, associated_ty_ids };
+    let trait_datum = TraitDatum { binders: make_binders(trait_datum_bound, bound_vars.len()) };
+    Arc::new(trait_datum)
+}
+
+pub(crate) fn struct_datum_query(
+    db: &impl HirDatabase,
+    krate: Crate,
+    struct_id: chalk_ir::StructId,
+) -> Arc<StructDatum> {
+    debug!("struct_datum {:?}", struct_id);
+    let type_ctor = from_chalk(db, struct_id);
+    debug!("struct {:?} = {:?}", struct_id, type_ctor);
+    // FIXME might be nicer if we can create a fake GenericParams for the TypeCtor
+    // FIXME extract this to a method on Ty
+    let (num_params, where_clauses, upstream) = match type_ctor {
+        TypeCtor::Bool
+        | TypeCtor::Char
+        | TypeCtor::Int(_)
+        | TypeCtor::Float(_)
+        | TypeCtor::Never
+        | TypeCtor::Str => (0, vec![], true),
+        TypeCtor::Slice | TypeCtor::Array | TypeCtor::RawPtr(_) | TypeCtor::Ref(_) => {
+            (1, vec![], true)
+        }
+        TypeCtor::FnPtr { num_args } => (num_args as usize + 1, vec![], true),
+        TypeCtor::Tuple { cardinality } => (cardinality as usize, vec![], true),
+        TypeCtor::FnDef(callable) => {
+            tested_by!(trait_resolution_on_fn_type);
+            let upstream = match callable {
+                CallableDef::Function(f) => f.module(db).krate(db),
+                CallableDef::Struct(s) => s.module(db).krate(db),
+                CallableDef::EnumVariant(v) => v.parent_enum(db).module(db).krate(db),
+            } != Some(krate);
+            let generic_def: GenericDef = match callable {
+                CallableDef::Function(f) => f.into(),
+                CallableDef::Struct(s) => s.into(),
+                CallableDef::EnumVariant(v) => v.parent_enum(db).into(),
+            };
+            let generic_params = generic_def.generic_params(db);
+            let bound_vars = Substs::bound_vars(&generic_params);
+            let where_clauses = convert_where_clauses(db, generic_def, &bound_vars);
+            (generic_params.count_params_including_parent(), where_clauses, upstream)
+        }
+        TypeCtor::Adt(adt) => {
+            let generic_params = adt.generic_params(db);
+            let bound_vars = Substs::bound_vars(&generic_params);
+            let where_clauses = convert_where_clauses(db, adt.into(), &bound_vars);
+            (
+                generic_params.count_params_including_parent(),
+                where_clauses,
+                adt.krate(db) != Some(krate),
+            )
+        }
+    };
+    let flags = chalk_rust_ir::StructFlags {
+        upstream,
+        // FIXME set fundamental flag correctly
+        fundamental: false,
+    };
+    let self_ty = chalk_ir::ApplicationTy {
+        name: TypeName::TypeKindId(type_ctor.to_chalk(db).into()),
+        parameters: (0..num_params).map(|i| chalk_ir::Ty::BoundVar(i).cast()).collect(),
+    };
+    let struct_datum_bound = chalk_rust_ir::StructDatumBound {
+        self_ty,
+        fields: Vec::new(), // FIXME add fields (only relevant for auto traits)
+        where_clauses,
+        flags,
+    };
+    let struct_datum = StructDatum { binders: make_binders(struct_datum_bound, num_params) };
+    Arc::new(struct_datum)
+}
+
+pub(crate) fn impl_datum_query(
+    db: &impl HirDatabase,
+    krate: Crate,
+    impl_id: ImplId,
+) -> Arc<ImplDatum> {
+    let _p = ra_prof::profile("impl_datum");
+    debug!("impl_datum {:?}", impl_id);
+    let impl_block: ImplBlock = from_chalk(db, impl_id);
+    let generic_params = impl_block.generic_params(db);
+    let bound_vars = Substs::bound_vars(&generic_params);
+    let trait_ref = impl_block
+        .target_trait_ref(db)
+        .expect("FIXME handle unresolved impl block trait ref")
+        .subst(&bound_vars);
+    let impl_type = if impl_block.module().krate(db) == Some(krate) {
+        chalk_rust_ir::ImplType::Local
+    } else {
+        chalk_rust_ir::ImplType::External
+    };
+    let where_clauses = convert_where_clauses(db, impl_block.into(), &bound_vars);
+    let negative = impl_block.is_negative(db);
+    debug!(
+        "impl {:?}: {}{} where {:?}",
+        impl_id,
+        if negative { "!" } else { "" },
+        trait_ref.display(db),
+        where_clauses
+    );
+    let trait_ = trait_ref.trait_;
+    let trait_ref = trait_ref.to_chalk(db);
+    let associated_ty_values = impl_block
+        .items(db)
+        .into_iter()
+        .filter_map(|item| match item {
+            ImplItem::TypeAlias(t) => Some(t),
+            _ => None,
+        })
+        .filter_map(|t| {
+            let assoc_ty = trait_.associated_type_by_name(db, t.name(db))?;
+            let ty = db.type_for_def(t.into(), crate::Namespace::Types).subst(&bound_vars);
+            Some(chalk_rust_ir::AssociatedTyValue {
+                impl_id,
+                associated_ty_id: assoc_ty.to_chalk(db),
+                value: chalk_ir::Binders {
+                    value: chalk_rust_ir::AssociatedTyValueBound { ty: ty.to_chalk(db) },
+                    binders: vec![], // we don't support GATs yet
+                },
+            })
+        })
+        .collect();
+
+    let impl_datum_bound = chalk_rust_ir::ImplDatumBound {
+        trait_ref: if negative {
+            chalk_rust_ir::PolarizedTraitRef::Negative(trait_ref)
+        } else {
+            chalk_rust_ir::PolarizedTraitRef::Positive(trait_ref)
+        },
+        where_clauses,
+        associated_ty_values,
+        impl_type,
+    };
+    debug!("impl_datum: {:?}", impl_datum_bound);
+    let impl_datum = ImplDatum { binders: make_binders(impl_datum_bound, bound_vars.len()) };
+    Arc::new(impl_datum)
+}
+
 fn id_from_chalk<T: InternKey>(chalk_id: chalk_ir::RawId) -> T {
     T::from_intern_id(InternId::from(chalk_id.index))
 }
diff --git a/crates/ra_ide_api/src/db.rs b/crates/ra_ide_api/src/db.rs
index 82b061419..cb7d30c43 100644
--- a/crates/ra_ide_api/src/db.rs
+++ b/crates/ra_ide_api/src/db.rs
@@ -14,6 +14,7 @@ use crate::{LineIndex, symbol_index::{self, SymbolsDatabase}};
     ra_db::SourceDatabaseStorage,
     LineIndexDatabaseStorage,
     symbol_index::SymbolsDatabaseStorage,
+    hir::db::InternDatabaseStorage,
     hir::db::AstDatabaseStorage,
     hir::db::DefDatabaseStorage,
     hir::db::HirDatabaseStorage
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 6373240d5..47222cd0a 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -621,17 +621,32 @@ pub fn handle_formatting(
 
     let output = rustfmt.wait_with_output()?;
     let captured_stdout = String::from_utf8(output.stdout)?;
+
     if !output.status.success() {
-        return Err(LspError::new(
-            -32900,
-            format!(
-                r#"rustfmt exited with:
-            Status: {}
-            stdout: {}"#,
-                output.status, captured_stdout,
-            ),
-        )
-        .into());
+        match output.status.code() {
+            Some(1) => {
+                // While `rustfmt` doesn't have a specific exit code for parse errors this is the
+                // likely cause exiting with 1. Most Language Servers swallow parse errors on
+                // formatting because otherwise an error is surfaced to the user on top of the
+                // syntax error diagnostics they're already receiving. This is especially jarring
+                // if they have format on save enabled.
+                log::info!("rustfmt exited with status 1, assuming parse error and ignoring");
+                return Ok(None);
+            }
+            _ => {
+                // Something else happened - e.g. `rustfmt` is missing or caught a signal
+                return Err(LspError::new(
+                    -32900,
+                    format!(
+                        r#"rustfmt exited with:
+                           Status: {}
+                           stdout: {}"#,
+                        output.status, captured_stdout,
+                    ),
+                )
+                .into());
+            }
+        }
     }
 
     Ok(Some(vec![TextEdit {
diff --git a/crates/ra_prof/Cargo.toml b/crates/ra_prof/Cargo.toml
index d55af18f5..787e18385 100644
--- a/crates/ra_prof/Cargo.toml
+++ b/crates/ra_prof/Cargo.toml
@@ -9,3 +9,4 @@ publish = false
 once_cell = "0.2.0"
 itertools = "0.8.0"
 backtrace = "0.3.28"
+cpuprofiler = { version = "0.0.3", optional = true }
diff --git a/crates/ra_prof/src/lib.rs b/crates/ra_prof/src/lib.rs
index de67b4031..1e8d780ab 100644
--- a/crates/ra_prof/src/lib.rs
+++ b/crates/ra_prof/src/lib.rs
@@ -255,6 +255,39 @@ impl Drop for Scope {
     }
 }
 
+/// A wrapper around https://github.com/AtheMathmo/cpuprofiler
+///
+/// It can be used to capture sampling profiles of sections of code.
+/// It is not exactly out-of-the-box, as it relies on gperftools.
+/// See the docs for the crate for more!
+#[derive(Debug)]
+pub struct CpuProfiler {
+    _private: (),
+}
+
+pub fn cpu_profiler() -> CpuProfiler {
+    #[cfg(feature = "cpuprofiler")]
+    {
+        cpuprofiler::PROFILER.lock().unwrap().start("./out.profile").unwrap();
+    }
+
+    #[cfg(not(feature = "cpuprofiler"))]
+    {
+        eprintln!("cpuprofiler feature is disabled")
+    }
+
+    CpuProfiler { _private: () }
+}
+
+impl Drop for CpuProfiler {
+    fn drop(&mut self) {
+        #[cfg(feature = "cpuprofiler")]
+        {
+            cpuprofiler::PROFILER.lock().unwrap().stop().unwrap();
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;