26 files changed, 245 insertions, 313 deletions

diff --git a/crates/ra_hir/src/adt.rs b/crates/ra_hir/src/adt.rs
index bcb705c24..57d112f74 100644
--- a/crates/ra_hir/src/adt.rs
+++ b/crates/ra_hir/src/adt.rs
@@ -19,7 +19,7 @@ impl Struct {
     }
 
     pub(crate) fn variant_data(&self, db: &impl HirDatabase) -> Cancelable<Arc<VariantData>> {
-        Ok(db.struct_data(self.def_id)?.variant_data.clone())
+        Ok(db.struct_data(self.def_id).variant_data.clone())
     }
 }
 
@@ -37,16 +37,13 @@ impl StructData {
         StructData { name, variant_data }
     }
 
-    pub(crate) fn struct_data_query(
-        db: &impl HirDatabase,
-        def_id: DefId,
-    ) -> Cancelable<Arc<StructData>> {
+    pub(crate) fn struct_data_query(db: &impl HirDatabase, def_id: DefId) -> Arc<StructData> {
         let def_loc = def_id.loc(db);
         assert!(def_loc.kind == DefKind::Struct);
         let syntax = db.file_item(def_loc.source_item_id);
         let struct_def =
             ast::StructDef::cast(&syntax).expect("struct def should point to StructDef node");
-        Ok(Arc::new(StructData::new(struct_def)))
+        Arc::new(StructData::new(struct_def))
     }
 }
 
@@ -84,10 +81,7 @@ impl EnumData {
         EnumData { name, variants }
     }
 
-    pub(crate) fn enum_data_query(
-        db: &impl HirDatabase,
-        def_id: DefId,
-    ) -> Cancelable<Arc<EnumData>> {
+    pub(crate) fn enum_data_query(db: &impl HirDatabase, def_id: DefId) -> Arc<EnumData> {
         let def_loc = def_id.loc(db);
         assert!(def_loc.kind == DefKind::Enum);
         let syntax = db.file_item(def_loc.source_item_id);
@@ -107,7 +101,7 @@ impl EnumData {
         } else {
             Vec::new()
         };
-        Ok(Arc::new(EnumData::new(enum_def, variants)))
+        Arc::new(EnumData::new(enum_def, variants))
     }
 }
 
@@ -133,7 +127,7 @@ impl EnumVariantData {
     pub(crate) fn enum_variant_data_query(
         db: &impl HirDatabase,
         def_id: DefId,
-    ) -> Cancelable<Arc<EnumVariantData>> {
+    ) -> Arc<EnumVariantData> {
         let def_loc = def_id.loc(db);
         assert!(def_loc.kind == DefKind::EnumVariant);
         let syntax = db.file_item(def_loc.source_item_id);
@@ -146,10 +140,7 @@ impl EnumVariantData {
             .expect("enum variant list should have enum ancestor");
         let enum_def_id = get_def_id(db, &def_loc, enum_node, DefKind::Enum);
 
-        Ok(Arc::new(EnumVariantData::new(
-            variant_def,
-            Enum::new(enum_def_id),
-        )))
+        Arc::new(EnumVariantData::new(variant_def, Enum::new(enum_def_id)))
     }
 }
 
diff --git a/crates/ra_hir/src/code_model_api.rs b/crates/ra_hir/src/code_model_api.rs
index 5db53a34f..7ccd29e2f 100644
--- a/crates/ra_hir/src/code_model_api.rs
+++ b/crates/ra_hir/src/code_model_api.rs
@@ -33,10 +33,10 @@ impl Crate {
     pub fn crate_id(&self) -> CrateId {
         self.crate_id
     }
-    pub fn dependencies(&self, db: &impl HirDatabase) -> Cancelable<Vec<CrateDependency>> {
-        Ok(self.dependencies_impl(db))
+    pub fn dependencies(&self, db: &impl HirDatabase) -> Vec<CrateDependency> {
+        self.dependencies_impl(db)
     }
-    pub fn root_module(&self, db: &impl HirDatabase) -> Cancelable<Option<Module>> {
+    pub fn root_module(&self, db: &impl HirDatabase) -> Option<Module> {
         self.root_module_impl(db)
     }
 }
@@ -78,12 +78,12 @@ pub enum Problem {
 
 impl Module {
     /// Name of this module.
-    pub fn name(&self, db: &impl HirDatabase) -> Cancelable<Option<Name>> {
+    pub fn name(&self, db: &impl HirDatabase) -> Option<Name> {
         self.name_impl(db)
     }
 
     /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
-    pub fn definition_source(&self, db: &impl HirDatabase) -> Cancelable<(FileId, ModuleSource)> {
+    pub fn definition_source(&self, db: &impl HirDatabase) -> (FileId, ModuleSource) {
         self.definition_source_impl(db)
     }
 
@@ -92,19 +92,19 @@ impl Module {
     pub fn declaration_source(
         &self,
         db: &impl HirDatabase,
-    ) -> Cancelable<Option<(FileId, TreeArc<ast::Module>)>> {
+    ) -> Option<(FileId, TreeArc<ast::Module>)> {
         self.declaration_source_impl(db)
     }
 
     /// Returns the crate this module is part of.
-    pub fn krate(&self, db: &impl HirDatabase) -> Cancelable<Option<Crate>> {
+    pub fn krate(&self, db: &impl HirDatabase) -> Option<Crate> {
         self.krate_impl(db)
     }
 
     /// Topmost parent of this module. Every module has a `crate_root`, but some
     /// might be missing `krate`. This can happen if a module's file is not included
     /// in the module tree of any target in Cargo.toml.
-    pub fn crate_root(&self, db: &impl HirDatabase) -> Cancelable<Module> {
+    pub fn crate_root(&self, db: &impl HirDatabase) -> Module {
         self.crate_root_impl(db)
     }
 
@@ -114,31 +114,31 @@ impl Module {
     }
 
     /// Iterates over all child modules.
-    pub fn children(&self, db: &impl HirDatabase) -> Cancelable<impl Iterator<Item = Module>> {
+    pub fn children(&self, db: &impl HirDatabase) -> impl Iterator<Item = Module> {
         self.children_impl(db)
     }
 
     /// Finds a parent module.
-    pub fn parent(&self, db: &impl HirDatabase) -> Cancelable<Option<Module>> {
+    pub fn parent(&self, db: &impl HirDatabase) -> Option<Module> {
         self.parent_impl(db)
     }
 
-    pub fn path_to_root(&self, db: &impl HirDatabase) -> Cancelable<Vec<Module>> {
+    pub fn path_to_root(&self, db: &impl HirDatabase) -> Vec<Module> {
         let mut res = vec![self.clone()];
         let mut curr = self.clone();
-        while let Some(next) = curr.parent(db)? {
+        while let Some(next) = curr.parent(db) {
             res.push(next.clone());
             curr = next
         }
-        Ok(res)
+        res
     }
 
     /// Returns a `ModuleScope`: a set of items, visible in this module.
-    pub fn scope(&self, db: &impl HirDatabase) -> Cancelable<ModuleScope> {
+    pub fn scope(&self, db: &impl HirDatabase) -> ModuleScope {
         self.scope_impl(db)
     }
 
-    pub fn resolve_path(&self, db: &impl HirDatabase, path: &Path) -> Cancelable<PerNs<DefId>> {
+    pub fn resolve_path(&self, db: &impl HirDatabase, path: &Path) -> PerNs<DefId> {
         self.resolve_path_impl(db, path)
     }
 
@@ -175,13 +175,12 @@ impl Struct {
         self.def_id
     }
 
-    pub fn name(&self, db: &impl HirDatabase) -> Cancelable<Option<Name>> {
-        Ok(db.struct_data(self.def_id)?.name.clone())
+    pub fn name(&self, db: &impl HirDatabase) -> Option<Name> {
+        db.struct_data(self.def_id).name.clone()
     }
 
-    pub fn fields(&self, db: &impl HirDatabase) -> Cancelable<Vec<StructField>> {
-        let res = db
-            .struct_data(self.def_id)?
+    pub fn fields(&self, db: &impl HirDatabase) -> Vec<StructField> {
+        db.struct_data(self.def_id)
             .variant_data
             .fields()
             .iter()
@@ -189,15 +188,11 @@ impl Struct {
                 struct_: self.clone(),
                 name: it.name.clone(),
             })
-            .collect();
-        Ok(res)
+            .collect()
     }
 
-    pub fn source(
-        &self,
-        db: &impl HirDatabase,
-    ) -> Cancelable<(HirFileId, TreeArc<ast::StructDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::StructDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
 
@@ -215,16 +210,16 @@ impl Enum {
         self.def_id
     }
 
-    pub fn name(&self, db: &impl HirDatabase) -> Cancelable<Option<Name>> {
-        Ok(db.enum_data(self.def_id)?.name.clone())
+    pub fn name(&self, db: &impl HirDatabase) -> Option<Name> {
+        db.enum_data(self.def_id).name.clone()
     }
 
-    pub fn variants(&self, db: &impl HirDatabase) -> Cancelable<Vec<(Name, EnumVariant)>> {
-        Ok(db.enum_data(self.def_id)?.variants.clone())
+    pub fn variants(&self, db: &impl HirDatabase) -> Vec<(Name, EnumVariant)> {
+        db.enum_data(self.def_id).variants.clone()
     }
 
-    pub fn source(&self, db: &impl HirDatabase) -> Cancelable<(HirFileId, TreeArc<ast::EnumDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::EnumDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
 
@@ -242,23 +237,20 @@ impl EnumVariant {
         self.def_id
     }
 
-    pub fn parent_enum(&self, db: &impl HirDatabase) -> Cancelable<Enum> {
-        Ok(db.enum_variant_data(self.def_id)?.parent_enum.clone())
+    pub fn parent_enum(&self, db: &impl HirDatabase) -> Enum {
+        db.enum_variant_data(self.def_id).parent_enum.clone()
     }
 
-    pub fn name(&self, db: &impl HirDatabase) -> Cancelable<Option<Name>> {
-        Ok(db.enum_variant_data(self.def_id)?.name.clone())
+    pub fn name(&self, db: &impl HirDatabase) -> Option<Name> {
+        db.enum_variant_data(self.def_id).name.clone()
     }
 
-    pub fn variant_data(&self, db: &impl HirDatabase) -> Cancelable<Arc<VariantData>> {
-        Ok(db.enum_variant_data(self.def_id)?.variant_data.clone())
+    pub fn variant_data(&self, db: &impl HirDatabase) -> Arc<VariantData> {
+        db.enum_variant_data(self.def_id).variant_data.clone()
     }
 
-    pub fn source(
-        &self,
-        db: &impl HirDatabase,
-    ) -> Cancelable<(HirFileId, TreeArc<ast::EnumVariant>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::EnumVariant>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
 
@@ -305,21 +297,21 @@ impl Function {
         self.def_id
     }
 
-    pub fn source(&self, db: &impl HirDatabase) -> Cancelable<(HirFileId, TreeArc<ast::FnDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::FnDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 
-    pub fn body_syntax_mapping(&self, db: &impl HirDatabase) -> Cancelable<Arc<BodySyntaxMapping>> {
+    pub fn body_syntax_mapping(&self, db: &impl HirDatabase) -> Arc<BodySyntaxMapping> {
         db.body_syntax_mapping(self.def_id)
     }
 
-    pub fn scopes(&self, db: &impl HirDatabase) -> Cancelable<ScopesWithSyntaxMapping> {
-        let scopes = db.fn_scopes(self.def_id)?;
-        let syntax_mapping = db.body_syntax_mapping(self.def_id)?;
-        Ok(ScopesWithSyntaxMapping {
+    pub fn scopes(&self, db: &impl HirDatabase) -> ScopesWithSyntaxMapping {
+        let scopes = db.fn_scopes(self.def_id);
+        let syntax_mapping = db.body_syntax_mapping(self.def_id);
+        ScopesWithSyntaxMapping {
             scopes,
             syntax_mapping,
-        })
+        }
     }
 
     pub fn signature(&self, db: &impl HirDatabase) -> Arc<FnSignature> {
@@ -341,8 +333,8 @@ impl Const {
         Const { def_id }
     }
 
-    pub fn source(&self, db: &impl HirDatabase) -> Cancelable<(HirFileId, TreeArc<ast::ConstDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::ConstDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
 
@@ -356,11 +348,8 @@ impl Static {
         Static { def_id }
     }
 
-    pub fn source(
-        &self,
-        db: &impl HirDatabase,
-    ) -> Cancelable<(HirFileId, TreeArc<ast::StaticDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::StaticDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
 
@@ -374,8 +363,8 @@ impl Trait {
         Trait { def_id }
     }
 
-    pub fn source(&self, db: &impl HirDatabase) -> Cancelable<(HirFileId, TreeArc<ast::TraitDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::TraitDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
 
@@ -389,7 +378,7 @@ impl Type {
         Type { def_id }
     }
 
-    pub fn source(&self, db: &impl HirDatabase) -> Cancelable<(HirFileId, TreeArc<ast::TypeDef>)> {
-        Ok(def_id_to_ast(db, self.def_id))
+    pub fn source(&self, db: &impl HirDatabase) -> (HirFileId, TreeArc<ast::TypeDef>) {
+        def_id_to_ast(db, self.def_id)
     }
 }
diff --git a/crates/ra_hir/src/code_model_impl/function.rs b/crates/ra_hir/src/code_model_impl/function.rs
index 8d6b7fc19..66d7e1713 100644
--- a/crates/ra_hir/src/code_model_impl/function.rs
+++ b/crates/ra_hir/src/code_model_impl/function.rs
@@ -2,7 +2,6 @@ mod scope;
 
 use std::sync::Arc;
 
-use ra_db::Cancelable;
 use ra_syntax::{TreeArc, ast::{self, NameOwner}};
 
 use crate::{
@@ -20,16 +19,16 @@ impl Function {
         Function { def_id }
     }
 
-    pub(crate) fn body(&self, db: &impl HirDatabase) -> Cancelable<Arc<Body>> {
+    pub(crate) fn body(&self, db: &impl HirDatabase) -> Arc<Body> {
         db.body_hir(self.def_id)
     }
 
-    pub(crate) fn module(&self, db: &impl HirDatabase) -> Cancelable<Module> {
+    pub(crate) fn module(&self, db: &impl HirDatabase) -> Module {
         self.def_id.module(db)
     }
 
     /// The containing impl block, if this is a method.
-    pub(crate) fn impl_block(&self, db: &impl HirDatabase) -> Cancelable<Option<ImplBlock>> {
+    pub(crate) fn impl_block(&self, db: &impl HirDatabase) -> Option<ImplBlock> {
         self.def_id.impl_block(db)
     }
 }
diff --git a/crates/ra_hir/src/code_model_impl/krate.rs b/crates/ra_hir/src/code_model_impl/krate.rs
index 712c6c86a..8c6e34873 100644
--- a/crates/ra_hir/src/code_model_impl/krate.rs
+++ b/crates/ra_hir/src/code_model_impl/krate.rs
@@ -1,4 +1,4 @@
-use ra_db::{CrateId, Cancelable};
+use ra_db::CrateId;
 
 use crate::{
     HirFileId, Crate, CrateDependency, AsName, DefLoc, DefKind, Module, SourceItemId,
@@ -20,7 +20,7 @@ impl Crate {
             })
             .collect()
     }
-    pub(crate) fn root_module_impl(&self, db: &impl HirDatabase) -> Cancelable<Option<Module>> {
+    pub(crate) fn root_module_impl(&self, db: &impl HirDatabase) -> Option<Module> {
         let crate_graph = db.crate_graph();
         let file_id = crate_graph.crate_root(self.crate_id);
         let source_root_id = db.file_source_root(file_id);
@@ -31,7 +31,7 @@ impl Crate {
             file_id,
             item_id: None,
         };
-        let module_id = ctry!(module_tree.find_module_by_source(source));
+        let module_id = module_tree.find_module_by_source(source)?;
 
         let def_loc = DefLoc {
             kind: DefKind::Module,
@@ -42,6 +42,6 @@ impl Crate {
         let def_id = def_loc.id(db);
 
         let module = Module::new(def_id);
-        Ok(Some(module))
+        Some(module)
     }
 }
diff --git a/crates/ra_hir/src/code_model_impl/module.rs b/crates/ra_hir/src/code_model_impl/module.rs
index 67808d282..04301ae53 100644
--- a/crates/ra_hir/src/code_model_impl/module.rs
+++ b/crates/ra_hir/src/code_model_impl/module.rs
@@ -30,17 +30,14 @@ impl Module {
         Module::new(def_id)
     }
 
-    pub(crate) fn name_impl(&self, db: &impl HirDatabase) -> Cancelable<Option<Name>> {
+    pub(crate) fn name_impl(&self, db: &impl HirDatabase) -> Option<Name> {
         let loc = self.def_id.loc(db);
         let module_tree = db.module_tree(loc.source_root_id);
-        let link = ctry!(loc.module_id.parent_link(&module_tree));
-        Ok(Some(link.name(&module_tree).clone()))
+        let link = loc.module_id.parent_link(&module_tree)?;
+        Some(link.name(&module_tree).clone())
     }
 
-    pub fn definition_source_impl(
-        &self,
-        db: &impl HirDatabase,
-    ) -> Cancelable<(FileId, ModuleSource)> {
+    pub fn definition_source_impl(&self, db: &impl HirDatabase) -> (FileId, ModuleSource) {
         let loc = self.def_id.loc(db);
         let file_id = loc.source_item_id.file_id.as_original_file();
         let syntax_node = db.file_item(loc.source_item_id);
@@ -50,40 +47,40 @@ impl Module {
             let module = ast::Module::cast(&syntax_node).unwrap();
             ModuleSource::Module(module.to_owned())
         };
-        Ok((file_id, module_source))
+        (file_id, module_source)
     }
 
     pub fn declaration_source_impl(
         &self,
         db: &impl HirDatabase,
-    ) -> Cancelable<Option<(FileId, TreeArc<ast::Module>)>> {
+    ) -> Option<(FileId, TreeArc<ast::Module>)> {
         let loc = self.def_id.loc(db);
         let module_tree = db.module_tree(loc.source_root_id);
-        let link = ctry!(loc.module_id.parent_link(&module_tree));
+        let link = loc.module_id.parent_link(&module_tree)?;
         let file_id = link
             .owner(&module_tree)
             .source(&module_tree)
             .file_id
             .as_original_file();
         let src = link.source(&module_tree, db);
-        Ok(Some((file_id, src)))
+        Some((file_id, src))
     }
 
-    pub(crate) fn krate_impl(&self, db: &impl HirDatabase) -> Cancelable<Option<Crate>> {
-        let root = self.crate_root(db)?;
+    pub(crate) fn krate_impl(&self, db: &impl HirDatabase) -> Option<Crate> {
+        let root = self.crate_root(db);
         let loc = root.def_id.loc(db);
         let file_id = loc.source_item_id.file_id.as_original_file();
 
         let crate_graph = db.crate_graph();
-        let crate_id = ctry!(crate_graph.crate_id_for_crate_root(file_id));
-        Ok(Some(Crate::new(crate_id)))
+        let crate_id = crate_graph.crate_id_for_crate_root(file_id)?;
+        Some(Crate::new(crate_id))
     }
 
-    pub(crate) fn crate_root_impl(&self, db: &impl HirDatabase) -> Cancelable<Module> {
+    pub(crate) fn crate_root_impl(&self, db: &impl HirDatabase) -> Module {
         let loc = self.def_id.loc(db);
         let module_tree = db.module_tree(loc.source_root_id);
         let module_id = loc.module_id.crate_root(&module_tree);
-        Ok(Module::from_module_id(db, loc.source_root_id, module_id))
+        Module::from_module_id(db, loc.source_root_id, module_id)
     }
 
     /// Finds a child module with the specified name.
@@ -95,7 +92,7 @@ impl Module {
     }
 
     /// Iterates over all child modules.
-    pub fn children_impl(&self, db: &impl HirDatabase) -> Cancelable<impl Iterator<Item = Module>> {
+    pub fn children_impl(&self, db: &impl HirDatabase) -> impl Iterator<Item = Module> {
         // FIXME this should be implementable without collecting into a vec, but
         // it's kind of hard since the iterator needs to keep a reference to the
         // module tree.
@@ -106,42 +103,33 @@ impl Module {
             .children(&module_tree)
             .map(|(_, module_id)| Module::from_module_id(db, loc.source_root_id, module_id))
             .collect::<Vec<_>>();
-        Ok(children.into_iter())
+        children.into_iter()
     }
 
-    pub fn parent_impl(&self, db: &impl HirDatabase) -> Cancelable<Option<Module>> {
+    pub fn parent_impl(&self, db: &impl HirDatabase) -> Option<Module> {
         let loc = self.def_id.loc(db);
         let module_tree = db.module_tree(loc.source_root_id);
-        let parent_id = ctry!(loc.module_id.parent(&module_tree));
-        Ok(Some(Module::from_module_id(
-            db,
-            loc.source_root_id,
-            parent_id,
-        )))
+        let parent_id = loc.module_id.parent(&module_tree)?;
+        Some(Module::from_module_id(db, loc.source_root_id, parent_id))
     }
 
     /// Returns a `ModuleScope`: a set of items, visible in this module.
-    pub fn scope_impl(&self, db: &impl HirDatabase) -> Cancelable<ModuleScope> {
+    pub fn scope_impl(&self, db: &impl HirDatabase) -> ModuleScope {
         let loc = self.def_id.loc(db);
-        let item_map = db.item_map(loc.source_root_id)?;
-        let res = item_map.per_module[&loc.module_id].clone();
-        Ok(res)
+        let item_map = db.item_map(loc.source_root_id);
+        item_map.per_module[&loc.module_id].clone()
     }
 
-    pub fn resolve_path_impl(
-        &self,
-        db: &impl HirDatabase,
-        path: &Path,
-    ) -> Cancelable<PerNs<DefId>> {
+    pub fn resolve_path_impl(&self, db: &impl HirDatabase, path: &Path) -> PerNs<DefId> {
         let mut curr_per_ns = PerNs::types(
             match path.kind {
-                PathKind::Crate => self.crate_root(db)?,
+                PathKind::Crate => self.crate_root(db),
                 PathKind::Self_ | PathKind::Plain => self.clone(),
                 PathKind::Super => {
-                    if let Some(p) = self.parent(db)? {
+                    if let Some(p) = self.parent(db) {
                         p
                     } else {
-                        return Ok(PerNs::none());
+                        return PerNs::none();
                     }
                 }
             }
@@ -153,39 +141,39 @@ impl Module {
             let curr = if let Some(r) = curr_per_ns.as_ref().take_types() {
                 r
             } else {
-                return Ok(PerNs::none());
+                return PerNs::none();
             };
-            let module = match curr.resolve(db)? {
+            let module = match curr.resolve(db) {
                 Def::Module(it) => it,
                 Def::Enum(e) => {
                     if segments.len() == idx + 1 {
                         // enum variant
                         let matching_variant =
-                            e.variants(db)?.into_iter().find(|(n, _variant)| n == name);
+                            e.variants(db).into_iter().find(|(n, _variant)| n == name);
 
                         if let Some((_n, variant)) = matching_variant {
-                            return Ok(PerNs::both(variant.def_id(), e.def_id()));
+                            return PerNs::both(variant.def_id(), e.def_id());
                         } else {
-                            return Ok(PerNs::none());
+                            return PerNs::none();
                         }
                     } else if segments.len() == idx {
                         // enum
-                        return Ok(PerNs::types(e.def_id()));
+                        return PerNs::types(e.def_id());
                     } else {
                         // malformed enum?
-                        return Ok(PerNs::none());
+                        return PerNs::none();
                     }
                 }
-                _ => return Ok(PerNs::none()),
+                _ => return PerNs::none(),
             };
-            let scope = module.scope(db)?;
+            let scope = module.scope(db);
             curr_per_ns = if let Some(r) = scope.get(&name) {
                 r.def_id
             } else {
-                return Ok(PerNs::none());
+                return PerNs::none();
             };
         }
-        Ok(curr_per_ns)
+        curr_per_ns
     }
 
     pub fn problems_impl(
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index 3b2498d5a..161a5e714 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -32,22 +32,22 @@ pub trait HirDatabase: SyntaxDatabase
         use fn crate::macros::expand_macro_invocation;
     }
 
-    fn fn_scopes(def_id: DefId) -> Cancelable<Arc<FnScopes>> {
+    fn fn_scopes(def_id: DefId) -> Arc<FnScopes> {
         type FnScopesQuery;
         use fn query_definitions::fn_scopes;
     }
 
-    fn struct_data(def_id: DefId) -> Cancelable<Arc<StructData>> {
+    fn struct_data(def_id: DefId) -> Arc<StructData> {
         type StructDataQuery;
         use fn crate::adt::StructData::struct_data_query;
     }
 
-    fn enum_data(def_id: DefId) -> Cancelable<Arc<EnumData>> {
+    fn enum_data(def_id: DefId) -> Arc<EnumData> {
         type EnumDataQuery;
         use fn crate::adt::EnumData::enum_data_query;
     }
 
-    fn enum_variant_data(def_id: DefId) -> Cancelable<Arc<EnumVariantData>> {
+    fn enum_variant_data(def_id: DefId) -> Arc<EnumVariantData> {
         type EnumVariantDataQuery;
         use fn crate::adt::EnumVariantData::enum_variant_data_query;
     }
@@ -87,7 +87,7 @@ pub trait HirDatabase: SyntaxDatabase
         use fn query_definitions::input_module_items;
     }
 
-    fn item_map(source_root_id: SourceRootId) -> Cancelable<Arc<ItemMap>> {
+    fn item_map(source_root_id: SourceRootId) -> Arc<ItemMap> {
         type ItemMapQuery;
         use fn query_definitions::item_map;
     }
@@ -97,7 +97,7 @@ pub trait HirDatabase: SyntaxDatabase
         use fn crate::module_tree::ModuleTree::module_tree_query;
     }
 
-    fn impls_in_module(source_root_id: SourceRootId, module_id: ModuleId) -> Cancelable<Arc<ModuleImplBlocks>> {
+    fn impls_in_module(source_root_id: SourceRootId, module_id: ModuleId) -> Arc<ModuleImplBlocks> {
         type ImplsInModuleQuery;
         use fn crate::impl_block::impls_in_module;
     }
@@ -107,12 +107,12 @@ pub trait HirDatabase: SyntaxDatabase
         use fn crate::ty::method_resolution::CrateImplBlocks::impls_in_crate_query;
     }
 
-    fn body_hir(def_id: DefId) -> Cancelable<Arc<crate::expr::Body>> {
+    fn body_hir(def_id: DefId) -> Arc<crate::expr::Body> {
         type BodyHirQuery;
         use fn crate::expr::body_hir;
     }
 
-    fn body_syntax_mapping(def_id: DefId) -> Cancelable<Arc<crate::expr::BodySyntaxMapping>> {
+    fn body_syntax_mapping(def_id: DefId) -> Arc<crate::expr::BodySyntaxMapping> {
         type BodySyntaxMappingQuery;
         use fn crate::expr::body_syntax_mapping;
     }
diff --git a/crates/ra_hir/src/expr.rs b/crates/ra_hir/src/expr.rs
index 5081466a2..4e8dc0c54 100644
--- a/crates/ra_hir/src/expr.rs
+++ b/crates/ra_hir/src/expr.rs
@@ -4,10 +4,8 @@ use std::sync::Arc;
 use rustc_hash::FxHashMap;
 
 use ra_arena::{Arena, RawId, impl_arena_id, map::ArenaMap};
-use ra_db::{LocalSyntaxPtr, Cancelable};
-use ra_syntax::{
-    ast::{self, AstNode, LoopBodyOwner, ArgListOwner, NameOwner, LiteralFlavor}
-};
+use ra_db::LocalSyntaxPtr;
+use ra_syntax::ast::{self, AstNode, LoopBodyOwner, ArgListOwner, NameOwner, LiteralFlavor};
 
 use crate::{Path, type_ref::{Mutability, TypeRef}, Name, HirDatabase, DefId, Def, name::AsName};
 use crate::ty::primitive::{UintTy, UncertainIntTy, UncertainFloatTy};
@@ -358,8 +356,8 @@ impl Pat {
 
 // Queries
 
-pub(crate) fn body_hir(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Arc<Body>> {
-    Ok(Arc::clone(&body_syntax_mapping(db, def_id)?.body))
+pub(crate) fn body_hir(db: &impl HirDatabase, def_id: DefId) -> Arc<Body> {
+    Arc::clone(&body_syntax_mapping(db, def_id).body)
 }
 
 struct ExprCollector {
@@ -828,17 +826,14 @@ pub(crate) fn collect_fn_body_syntax(node: &ast::FnDef) -> BodySyntaxMapping {
     collector.into_body_syntax_mapping(params, body)
 }
 
-pub(crate) fn body_syntax_mapping(
-    db: &impl HirDatabase,
-    def_id: DefId,
-) -> Cancelable<Arc<BodySyntaxMapping>> {
-    let def = def_id.resolve(db)?;
+pub(crate) fn body_syntax_mapping(db: &impl HirDatabase, def_id: DefId) -> Arc<BodySyntaxMapping> {
+    let def = def_id.resolve(db);
 
     let body_syntax_mapping = match def {
-        Def::Function(f) => collect_fn_body_syntax(&f.source(db)?.1),
+        Def::Function(f) => collect_fn_body_syntax(&f.source(db).1),
         // TODO: consts, etc.
         _ => panic!("Trying to get body for item type without body"),
     };
 
-    Ok(Arc::new(body_syntax_mapping))
+    Arc::new(body_syntax_mapping)
 }
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index d7cc9b4ca..0d8e67547 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -1,4 +1,4 @@
-use ra_db::{SourceRootId, LocationIntener, Cancelable, FileId};
+use ra_db::{SourceRootId, LocationIntener, FileId};
 use ra_syntax::{TreeArc, SyntaxKind, SyntaxNode, SourceFile, AstNode, ast};
 use ra_arena::{Arena, RawId, impl_arena_id};
 
@@ -159,9 +159,9 @@ impl DefId {
         db.as_ref().id2loc(self)
     }
 
-    pub fn resolve(self, db: &impl HirDatabase) -> Cancelable<Def> {
+    pub fn resolve(self, db: &impl HirDatabase) -> Def {
         let loc = self.loc(db);
-        let res = match loc.kind {
+        match loc.kind {
             DefKind::Module => {
                 let module = Module::from_module_id(db, loc.source_root_id, loc.module_id);
                 Def::Module(module)
@@ -195,8 +195,7 @@ impl DefId {
 
             DefKind::StructCtor => Def::Item,
             DefKind::Item => Def::Item,
-        };
-        Ok(res)
+        }
     }
 
     pub(crate) fn source(self, db: &impl HirDatabase) -> (HirFileId, TreeArc<SyntaxNode>) {
@@ -206,25 +205,21 @@ impl DefId {
     }
 
     /// For a module, returns that module; for any other def, returns the containing module.
-    pub fn module(self, db: &impl HirDatabase) -> Cancelable<Module> {
+    pub fn module(self, db: &impl HirDatabase) -> Module {
         let loc = self.loc(db);
-        Ok(Module::from_module_id(
-            db,
-            loc.source_root_id,
-            loc.module_id,
-        ))
+        Module::from_module_id(db, loc.source_root_id, loc.module_id)
     }
 
     /// Returns the containing crate.
-    pub fn krate(&self, db: &impl HirDatabase) -> Cancelable<Option<Crate>> {
-        Ok(self.module(db)?.krate(db)?)
+    pub fn krate(&self, db: &impl HirDatabase) -> Option<Crate> {
+        self.module(db).krate(db)
     }
 
     /// Returns the containing impl block, if this is an impl item.
-    pub fn impl_block(self, db: &impl HirDatabase) -> Cancelable<Option<ImplBlock>> {
+    pub fn impl_block(self, db: &impl HirDatabase) -> Option<ImplBlock> {
         let loc = self.loc(db);
-        let module_impls = db.impls_in_module(loc.source_root_id, loc.module_id)?;
-        Ok(ImplBlock::containing(module_impls, self))
+        let module_impls = db.impls_in_module(loc.source_root_id, loc.module_id);
+        ImplBlock::containing(module_impls, self)
     }
 }
 
diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index c9a9fb99f..ab996a12c 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -3,7 +3,7 @@ use rustc_hash::FxHashMap;
 
 use ra_arena::{Arena, RawId, impl_arena_id};
 use ra_syntax::ast::{self, AstNode};
-use ra_db::{LocationIntener, Cancelable, SourceRootId};
+use ra_db::{LocationIntener, SourceRootId};
 
 use crate::{
     DefId, DefLoc, DefKind, SourceItemId, SourceFileItems,
@@ -166,8 +166,8 @@ impl ModuleImplBlocks {
         }
     }
 
-    fn collect(&mut self, db: &impl HirDatabase, module: Module) -> Cancelable<()> {
-        let (file_id, module_source) = module.definition_source(db)?;
+    fn collect(&mut self, db: &impl HirDatabase, module: Module) {
+        let (file_id, module_source) = module.definition_source(db);
         let node = match &module_source {
             ModuleSource::SourceFile(node) => node.syntax(),
             ModuleSource::Module(node) => node
@@ -185,8 +185,6 @@ impl ModuleImplBlocks {
                 self.impls_by_def.insert(impl_item.def_id(), id);
             }
         }
-
-        Ok(())
     }
 }
 
@@ -194,9 +192,9 @@ pub(crate) fn impls_in_module(
     db: &impl HirDatabase,
     source_root_id: SourceRootId,
     module_id: ModuleId,
-) -> Cancelable<Arc<ModuleImplBlocks>> {
+) -> Arc<ModuleImplBlocks> {
     let mut result = ModuleImplBlocks::new();
     let module = Module::from_module_id(db, source_root_id, module_id);
-    result.collect(db, module)?;
-    Ok(Arc::new(result))
+    result.collect(db, module);
+    Arc::new(result)
 }
diff --git a/crates/ra_hir/src/nameres.rs b/crates/ra_hir/src/nameres.rs
index edb3b1e64..484f668d0 100644
--- a/crates/ra_hir/src/nameres.rs
+++ b/crates/ra_hir/src/nameres.rs
@@ -22,7 +22,7 @@ use ra_syntax::{
     SyntaxKind::{self, *},
     ast::{self, AstNode}
 };
-use ra_db::{SourceRootId, Cancelable, FileId};
+use ra_db::{SourceRootId, FileId};
 
 use crate::{
     HirFileId,
@@ -319,30 +319,26 @@ where
         }
     }
 
-    pub(crate) fn resolve(mut self) -> Cancelable<ItemMap> {
+    pub(crate) fn resolve(mut self) -> ItemMap {
         for (&module_id, items) in self.input.iter() {
-            self.populate_module(module_id, Arc::clone(items))?;
+            self.populate_module(module_id, Arc::clone(items));
         }
 
         loop {
             let processed_imports_count = self.processed_imports.len();
             for &module_id in self.input.keys() {
                 self.db.check_canceled();
-                self.resolve_imports(module_id)?;
+                self.resolve_imports(module_id);
             }
             if processed_imports_count == self.processed_imports.len() {
                 // no new imports resolved
                 break;
             }
         }
-        Ok(self.result)
+        self.result
     }
 
-    fn populate_module(
-        &mut self,
-        module_id: ModuleId,
-        input: Arc<InputModuleItems>,
-    ) -> Cancelable<()> {
+    fn populate_module(&mut self, module_id: ModuleId, input: Arc<InputModuleItems>) {
         let mut module_items = ModuleScope::default();
 
         // Populate extern crates prelude
@@ -353,8 +349,8 @@ where
             if let Some(crate_id) = crate_graph.crate_id_for_crate_root(file_id.as_original_file())
             {
                 let krate = Crate::new(crate_id);
-                for dep in krate.dependencies(self.db)? {
-                    if let Some(module) = dep.krate.root_module(self.db)? {
+                for dep in krate.dependencies(self.db) {
+                    if let Some(module) = dep.krate.root_module(self.db) {
                         let def_id = module.def_id;
                         self.add_module_item(
                             &mut module_items,
@@ -415,7 +411,6 @@ where
         }
 
         self.result.per_module.insert(module_id, module_items);
-        Ok(())
     }
 
     fn add_module_item(&self, module_items: &mut ModuleScope, name: Name, def_id: PerNs<DefId>) {
@@ -426,24 +421,23 @@ where
         module_items.items.insert(name, resolution);
     }
 
-    fn resolve_imports(&mut self, module_id: ModuleId) -> Cancelable<()> {
+    fn resolve_imports(&mut self, module_id: ModuleId) {
         for (i, import) in self.input[&module_id].imports.iter().enumerate() {
             if self.processed_imports.contains(&(module_id, i)) {
                 // already done
                 continue;
             }
-            if self.resolve_import(module_id, import)? {
+            if self.resolve_import(module_id, import) {
                 log::debug!("import {:?} resolved (or definite error)", import);
                 self.processed_imports.insert((module_id, i));
             }
         }
-        Ok(())
     }
 
-    fn resolve_import(&mut self, module_id: ModuleId, import: &Import) -> Cancelable<bool> {
+    fn resolve_import(&mut self, module_id: ModuleId, import: &Import) -> bool {
         log::debug!("resolving import: {:?}", import);
         let ptr = match import.kind {
-            ImportKind::Glob => return Ok(false),
+            ImportKind::Glob => return false,
             ImportKind::Named(ptr) => ptr,
         };
 
@@ -455,7 +449,7 @@ where
                     None => {
                         // TODO: error
                         log::debug!("super path in root module");
-                        return Ok(true); // this can't suddenly resolve if we just resolve some other imports
+                        return true; // this can't suddenly resolve if we just resolve some other imports
                     }
                 }
             }
@@ -469,7 +463,7 @@ where
                 Some(res) if !res.def_id.is_none() => res.def_id,
                 _ => {
                     log::debug!("path segment {:?} not found", name);
-                    return Ok(false);
+                    return false;
                 }
             };
 
@@ -481,7 +475,7 @@ where
                         "path segment {:?} resolved to value only, but is not last",
                         name
                     );
-                    return Ok(false);
+                    return false;
                 };
                 curr = match type_def_id.loc(self.db) {
                     DefLoc {
@@ -499,7 +493,7 @@ where
                                 kind: PathKind::Crate,
                             };
                             log::debug!("resolving {:?} in other source root", path);
-                            let def_id = module.resolve_path(self.db, &path)?;
+                            let def_id = module.resolve_path(self.db, &path);
                             if !def_id.is_none() {
                                 let name = path.segments.last().unwrap();
                                 self.update(module_id, |items| {
@@ -515,10 +509,10 @@ where
                                     import,
                                     def_id.map(|did| did.loc(self.db))
                                 );
-                                return Ok(true);
+                                return true;
                             } else {
                                 log::debug!("rest of path did not resolve in other source root");
-                                return Ok(true);
+                                return true;
                             }
                         }
                     }
@@ -528,7 +522,7 @@ where
                             name,
                             type_def_id.loc(self.db)
                         );
-                        return Ok(true); // this resolved to a non-module, so the path won't ever resolve
+                        return true; // this resolved to a non-module, so the path won't ever resolve
                     }
                 }
             } else {
@@ -547,7 +541,7 @@ where
                 })
             }
         }
-        Ok(true)
+        true
     }
 
     fn update(&mut self, module_id: ModuleId, f: impl FnOnce(&mut ModuleScope)) {
diff --git a/crates/ra_hir/src/nameres/tests.rs b/crates/ra_hir/src/nameres/tests.rs
index ea8ab4c83..9a0474045 100644
--- a/crates/ra_hir/src/nameres/tests.rs
+++ b/crates/ra_hir/src/nameres/tests.rs
@@ -17,7 +17,7 @@ fn item_map(fixture: &str) -> (Arc<ItemMap>, ModuleId) {
     let source_root = db.file_source_root(pos.file_id);
     let module = crate::source_binder::module_from_position(&db, pos).unwrap();
     let module_id = module.def_id.loc(&db).module_id;
-    (db.item_map(source_root).unwrap(), module_id)
+    (db.item_map(source_root), module_id)
 }
 
 fn check_module_item_map(map: &ItemMap, module_id: ModuleId, expected: &str) {
@@ -242,7 +242,7 @@ fn item_map_across_crates() {
     let source_root = db.file_source_root(main_id);
     let module = crate::source_binder::module_from_file_id(&db, main_id).unwrap();
     let module_id = module.def_id.loc(&db).module_id;
-    let item_map = db.item_map(source_root).unwrap();
+    let item_map = db.item_map(source_root);
 
     check_module_item_map(
         &item_map,
@@ -294,7 +294,7 @@ fn import_across_source_roots() {
 
     let module = crate::source_binder::module_from_file_id(&db, main_id).unwrap();
     let module_id = module.def_id.loc(&db).module_id;
-    let item_map = db.item_map(source_root).unwrap();
+    let item_map = db.item_map(source_root);
 
     check_module_item_map(
         &item_map,
@@ -337,7 +337,7 @@ fn reexport_across_crates() {
     let source_root = db.file_source_root(main_id);
     let module = crate::source_binder::module_from_file_id(&db, main_id).unwrap();
     let module_id = module.def_id.loc(&db).module_id;
-    let item_map = db.item_map(source_root).unwrap();
+    let item_map = db.item_map(source_root);
 
     check_module_item_map(
         &item_map,
@@ -354,7 +354,7 @@ fn check_item_map_is_not_recomputed(initial: &str, file_change: &str) {
     let source_root = db.file_source_root(pos.file_id);
     {
         let events = db.log_executed(|| {
-            db.item_map(source_root).unwrap();
+            db.item_map(source_root);
         });
         assert!(format!("{:?}", events).contains("item_map"))
     }
@@ -363,7 +363,7 @@ fn check_item_map_is_not_recomputed(initial: &str, file_change: &str) {
 
     {
         let events = db.log_executed(|| {
-            db.item_map(source_root).unwrap();
+            db.item_map(source_root);
         });
         assert!(
             !format!("{:?}", events).contains("item_map"),
diff --git a/crates/ra_hir/src/query_definitions.rs b/crates/ra_hir/src/query_definitions.rs
index 7ff942f6a..24cb5c752 100644
--- a/crates/ra_hir/src/query_definitions.rs
+++ b/crates/ra_hir/src/query_definitions.rs
@@ -8,7 +8,7 @@ use ra_syntax::{
     AstNode, SyntaxNode, TreeArc,
     ast::{self, ModuleItemOwner}
 };
-use ra_db::{SourceRootId, Cancelable,};
+use ra_db::SourceRootId;
 
 use crate::{
     SourceFileItems, SourceItemId, DefId, HirFileId, ModuleSource,
@@ -18,10 +18,10 @@ use crate::{
     nameres::{InputModuleItems, ItemMap, Resolver},
 };
 
-pub(super) fn fn_scopes(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Arc<FnScopes>> {
-    let body = db.body_hir(def_id)?;
+pub(super) fn fn_scopes(db: &impl HirDatabase, def_id: DefId) -> Arc<FnScopes> {
+    let body = db.body_hir(def_id);
     let res = FnScopes::new(body);
-    Ok(Arc::new(res))
+    Arc::new(res)
 }
 
 pub(super) fn file_items(db: &impl HirDatabase, file_id: HirFileId) -> Arc<SourceFileItems> {
@@ -93,10 +93,7 @@ pub(super) fn input_module_items(
     Arc::new(res)
 }
 
-pub(super) fn item_map(
-    db: &impl HirDatabase,
-    source_root: SourceRootId,
-) -> Cancelable<Arc<ItemMap>> {
+pub(super) fn item_map(db: &impl HirDatabase, source_root: SourceRootId) -> Arc<ItemMap> {
     let start = Instant::now();
     let module_tree = db.module_tree(source_root);
     let input = module_tree
@@ -105,8 +102,8 @@ pub(super) fn item_map(
         .collect::<FxHashMap<_, _>>();
 
     let resolver = Resolver::new(db, &input, source_root, module_tree);
-    let res = resolver.resolve()?;
+    let res = resolver.resolve();
     let elapsed = start.elapsed();
     log::info!("item_map: {:?}", elapsed);
-    Ok(Arc::new(res))
+    Arc::new(res)
 }
diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index 03787bd89..e5f8ffc2e 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -349,7 +349,7 @@ impl Ty {
         }
 
         // Resolve in module (in type namespace)
-        let resolved = if let Some(r) = module.resolve_path(db, path)?.take_types() {
+        let resolved = if let Some(r) = module.resolve_path(db, path).take_types() {
             r
         } else {
             return Ok(Ty::Unknown);
@@ -447,8 +447,8 @@ impl fmt::Display for Ty {
 /// function body.
 fn type_for_fn(db: &impl HirDatabase, f: Function) -> Cancelable<Ty> {
     let signature = f.signature(db);
-    let module = f.module(db)?;
-    let impl_block = f.impl_block(db)?;
+    let module = f.module(db);
+    let impl_block = f.impl_block(db);
     // TODO we ignore type parameters for now
     let input = signature
         .params()
@@ -463,25 +463,25 @@ fn type_for_fn(db: &impl HirDatabase, f: Function) -> Cancelable<Ty> {
 fn type_for_struct(db: &impl HirDatabase, s: Struct) -> Cancelable<Ty> {
     Ok(Ty::Adt {
         def_id: s.def_id(),
-        name: s.name(db)?.unwrap_or_else(Name::missing),
+        name: s.name(db).unwrap_or_else(Name::missing),
     })
 }
 
 pub(crate) fn type_for_enum(db: &impl HirDatabase, s: Enum) -> Cancelable<Ty> {
     Ok(Ty::Adt {
         def_id: s.def_id(),
-        name: s.name(db)?.unwrap_or_else(Name::missing),
+        name: s.name(db).unwrap_or_else(Name::missing),
     })
 }
 
 pub(crate) fn type_for_enum_variant(db: &impl HirDatabase, ev: EnumVariant) -> Cancelable<Ty> {
-    let enum_parent = ev.parent_enum(db)?;
+    let enum_parent = ev.parent_enum(db);
 
     type_for_enum(db, enum_parent)
 }
 
 pub(super) fn type_for_def(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Ty> {
-    let def = def_id.resolve(db)?;
+    let def = def_id.resolve(db);
     match def {
         Def::Module(..) => {
             log::debug!("trying to get type for module {:?}", def_id);
@@ -507,18 +507,18 @@ pub(super) fn type_for_field(
     def_id: DefId,
     field: Name,
 ) -> Cancelable<Option<Ty>> {
-    let def = def_id.resolve(db)?;
+    let def = def_id.resolve(db);
     let variant_data = match def {
         Def::Struct(s) => s.variant_data(db)?,
-        Def::EnumVariant(ev) => ev.variant_data(db)?,
+        Def::EnumVariant(ev) => ev.variant_data(db),
         // TODO: unions
         _ => panic!(
             "trying to get type for field in non-struct/variant {:?}",
             def_id
         ),
     };
-    let module = def_id.module(db)?;
-    let impl_block = def_id.impl_block(db)?;
+    let module = def_id.module(db);
+    let impl_block = def_id.impl_block(db);
     let type_ref = ctry!(variant_data.get_field_type_ref(&field));
     Ok(Some(Ty::from_hir(
         db,
@@ -860,7 +860,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         };
 
         // resolve in module
-        let resolved = ctry!(self.module.resolve_path(self.db, &path)?.take_values());
+        let resolved = ctry!(self.module.resolve_path(self.db, &path).take_values());
         let ty = self.db.type_for_def(resolved)?;
         let ty = self.insert_type_vars(ty);
         Ok(Some(ty))
@@ -872,12 +872,12 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         } else {
             return Ok((Ty::Unknown, None));
         };
-        let def_id = if let Some(def_id) = self.module.resolve_path(self.db, &path)?.take_types() {
+        let def_id = if let Some(def_id) = self.module.resolve_path(self.db, &path).take_types() {
             def_id
         } else {
             return Ok((Ty::Unknown, None));
         };
-        Ok(match def_id.resolve(self.db)? {
+        Ok(match def_id.resolve(self.db) {
             Def::Struct(s) => {
                 let ty = type_for_struct(self.db, s)?;
                 (ty, Some(def_id))
@@ -1205,10 +1205,10 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 pub fn infer(db: &impl HirDatabase, def_id: DefId) -> Cancelable<Arc<InferenceResult>> {
     db.check_canceled();
     let function = Function::new(def_id); // TODO: consts also need inference
-    let body = function.body(db)?;
-    let scopes = db.fn_scopes(def_id)?;
-    let module = function.module(db)?;
-    let impl_block = function.impl_block(db)?;
+    let body = function.body(db);
+    let scopes = db.fn_scopes(def_id);
+    let module = function.module(db);
+    let impl_block = function.impl_block(db);
     let mut ctx = InferenceContext::new(db, body, scopes, module, impl_block);
 
     let signature = function.signature(db);
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 7c3839388..94c5124a9 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -49,14 +49,14 @@ impl CrateImplBlocks {
             .into_iter()
             .flat_map(|i| i.iter())
             .map(move |(module_id, impl_id)| {
-                let module_impl_blocks = db.impls_in_module(self.source_root_id, *module_id)?;
+                let module_impl_blocks = db.impls_in_module(self.source_root_id, *module_id);
                 Ok(ImplBlock::from_id(module_impl_blocks, *impl_id))
             })
     }
 
     fn collect_recursive(&mut self, db: &impl HirDatabase, module: Module) -> Cancelable<()> {
         let module_id = module.def_id.loc(db).module_id;
-        let module_impl_blocks = db.impls_in_module(self.source_root_id, module_id)?;
+        let module_impl_blocks = db.impls_in_module(self.source_root_id, module_id);
 
         for (impl_id, impl_data) in module_impl_blocks.impls.iter() {
             let impl_block = ImplBlock::from_id(Arc::clone(&module_impl_blocks), impl_id);
@@ -75,7 +75,7 @@ impl CrateImplBlocks {
             }
         }
 
-        for child in module.children(db)? {
+        for child in module.children(db) {
             self.collect_recursive(db, child)?;
         }
 
@@ -93,17 +93,17 @@ impl CrateImplBlocks {
             source_root_id,
             impls: FxHashMap::default(),
         };
-        if let Some(module) = krate.root_module(db)? {
+        if let Some(module) = krate.root_module(db) {
             crate_impl_blocks.collect_recursive(db, module)?;
         }
         Ok(Arc::new(crate_impl_blocks))
     }
 }
 
-fn def_crate(db: &impl HirDatabase, ty: &Ty) -> Cancelable<Option<Crate>> {
+fn def_crate(db: &impl HirDatabase, ty: &Ty) -> Option<Crate> {
     match ty {
         Ty::Adt { def_id, .. } => def_id.krate(db),
-        _ => Ok(None),
+        _ => None,
     }
 }
 
@@ -139,7 +139,7 @@ impl Ty {
         // rustc does an autoderef and then autoref again).
 
         for derefed_ty in self.autoderef(db) {
-            let krate = match def_crate(db, &derefed_ty)? {
+            let krate = match def_crate(db, &derefed_ty) {
                 Some(krate) => krate,
                 None => continue,
             };
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index b81d91e80..b44ac9987 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -322,7 +322,7 @@ fn infer(content: &str) -> String {
     {
         let func = source_binder::function_from_source(&db, file_id, fn_def).unwrap();
         let inference_result = func.infer(&db).unwrap();
-        let body_syntax_mapping = func.body_syntax_mapping(&db).unwrap();
+        let body_syntax_mapping = func.body_syntax_mapping(&db);
         let mut types = Vec::new();
         for (pat, ty) in inference_result.type_of_pat.iter() {
             let syntax_ptr = match body_syntax_mapping.pat_syntax(pat) {
diff --git a/crates/ra_ide_api/src/completion/complete_dot.rs b/crates/ra_ide_api/src/completion/complete_dot.rs
index 37985b398..cb86ba9a3 100644
--- a/crates/ra_ide_api/src/completion/complete_dot.rs
+++ b/crates/ra_ide_api/src/completion/complete_dot.rs
@@ -10,7 +10,7 @@ pub(super) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) -> Ca
         _ => return Ok(()),
     };
     let infer_result = function.infer(ctx.db)?;
-    let syntax_mapping = function.body_syntax_mapping(ctx.db)?;
+    let syntax_mapping = function.body_syntax_mapping(ctx.db);
     let expr = match syntax_mapping.node_expr(receiver) {
         Some(expr) => expr,
         None => return Ok(()),
@@ -27,9 +27,9 @@ fn complete_fields(acc: &mut Completions, ctx: &CompletionContext, receiver: Ty)
     for receiver in receiver.autoderef(ctx.db) {
         match receiver {
             Ty::Adt { def_id, .. } => {
-                match def_id.resolve(ctx.db)? {
+                match def_id.resolve(ctx.db) {
                     Def::Struct(s) => {
-                        for field in s.fields(ctx.db)? {
+                        for field in s.fields(ctx.db) {
                             CompletionItem::new(
                                 CompletionKind::Reference,
                                 field.name().to_string(),
diff --git a/crates/ra_ide_api/src/completion/complete_path.rs b/crates/ra_ide_api/src/completion/complete_path.rs
index a25ad3f13..42468681a 100644
--- a/crates/ra_ide_api/src/completion/complete_path.rs
+++ b/crates/ra_ide_api/src/completion/complete_path.rs
@@ -8,13 +8,13 @@ pub(super) fn complete_path(acc: &mut Completions, ctx: &CompletionContext) -> C
         (Some(path), Some(module)) => (path.clone(), module),
         _ => return Ok(()),
     };
-    let def_id = match module.resolve_path(ctx.db, &path)?.take_types() {
+    let def_id = match module.resolve_path(ctx.db, &path).take_types() {
         Some(it) => it,
         None => return Ok(()),
     };
-    match def_id.resolve(ctx.db)? {
+    match def_id.resolve(ctx.db) {
         hir::Def::Module(module) => {
-            let module_scope = module.scope(ctx.db)?;
+            let module_scope = module.scope(ctx.db);
             for (name, res) in module_scope.entries() {
                 CompletionItem::new(CompletionKind::Reference, name.to_string())
                     .from_resolution(ctx, res)
@@ -22,7 +22,7 @@ pub(super) fn complete_path(acc: &mut Completions, ctx: &CompletionContext) -> C
             }
         }
         hir::Def::Enum(e) => {
-            e.variants(ctx.db)?
+            e.variants(ctx.db)
                 .into_iter()
                 .for_each(|(variant_name, _variant)| {
                     CompletionItem::new(CompletionKind::Reference, variant_name.to_string())
diff --git a/crates/ra_ide_api/src/completion/complete_scope.rs b/crates/ra_ide_api/src/completion/complete_scope.rs
index 770a0fdf2..660c7d16e 100644
--- a/crates/ra_ide_api/src/completion/complete_scope.rs
+++ b/crates/ra_ide_api/src/completion/complete_scope.rs
@@ -15,12 +15,12 @@ pub(super) fn complete_scope(acc: &mut Completions, ctx: &CompletionContext) ->
         None => return Ok(()),
     };
     if let Some(function) = &ctx.function {
-        let scopes = function.scopes(ctx.db)?;
+        let scopes = function.scopes(ctx.db);
         complete_fn(acc, &scopes, ctx.offset);
     }
 
-    let module_scope = module.scope(ctx.db)?;
-    let (file_id, _) = module.definition_source(ctx.db)?;
+    let module_scope = module.scope(ctx.db);
+    let (file_id, _) = module.definition_source(ctx.db);
     module_scope
         .entries()
         .filter(|(_name, res)| {
diff --git a/crates/ra_ide_api/src/completion/completion_item.rs b/crates/ra_ide_api/src/completion/completion_item.rs
index b75d65de3..11d00f78c 100644
--- a/crates/ra_ide_api/src/completion/completion_item.rs
+++ b/crates/ra_ide_api/src/completion/completion_item.rs
@@ -144,7 +144,7 @@ impl Builder {
         ctx: &CompletionContext,
         resolution: &hir::Resolution,
     ) -> Builder {
-        let resolved = resolution.def_id.and_then(|d| d.resolve(ctx.db).ok());
+        let resolved = resolution.def_id.map(|d| d.resolve(ctx.db));
         let kind = match resolved {
             PerNs {
                 types: Some(hir::Def::Module(..)),
diff --git a/crates/ra_ide_api/src/goto_definition.rs b/crates/ra_ide_api/src/goto_definition.rs
index 591f36cce..cdd8e211d 100644
--- a/crates/ra_ide_api/src/goto_definition.rs
+++ b/crates/ra_ide_api/src/goto_definition.rs
@@ -50,7 +50,7 @@ pub(crate) fn reference_definition(
     if let Some(function) =
         hir::source_binder::function_from_child_node(db, file_id, name_ref.syntax())
     {
-        let scope = function.scopes(db)?;
+        let scope = function.scopes(db);
         // First try to resolve the symbol locally
         if let Some(entry) = scope.resolve_local_name(name_ref) {
             let nav = NavigationTarget::from_scope_entry(file_id, &entry);
@@ -64,13 +64,13 @@ pub(crate) fn reference_definition(
             .and_then(ast::MethodCallExpr::cast)
         {
             let infer_result = function.infer(db)?;
-            let syntax_mapping = function.body_syntax_mapping(db)?;
+            let syntax_mapping = function.body_syntax_mapping(db);
             let expr = ast::Expr::cast(method_call.syntax()).unwrap();
             if let Some(def_id) = syntax_mapping
                 .node_expr(expr)
                 .and_then(|it| infer_result.method_resolution(it))
             {
-                if let Some(target) = NavigationTarget::from_def(db, def_id.resolve(db)?)? {
+                if let Some(target) = NavigationTarget::from_def(db, def_id.resolve(db)) {
                     return Ok(Exact(target));
                 }
             };
@@ -85,9 +85,9 @@ pub(crate) fn reference_definition(
             .find_map(ast::Path::cast)
             .and_then(hir::Path::from_ast)
         {
-            let resolved = module.resolve_path(db, &path)?;
+            let resolved = module.resolve_path(db, &path);
             if let Some(def_id) = resolved.take_types().or(resolved.take_values()) {
-                if let Some(target) = NavigationTarget::from_def(db, def_id.resolve(db)?)? {
+                if let Some(target) = NavigationTarget::from_def(db, def_id.resolve(db)) {
                     return Ok(Exact(target));
                 }
             }
@@ -112,7 +112,7 @@ fn name_definition(
             if let Some(child_module) =
                 hir::source_binder::module_from_declaration(db, file_id, module)
             {
-                let nav = NavigationTarget::from_module(db, child_module)?;
+                let nav = NavigationTarget::from_module(db, child_module);
                 return Ok(Some(vec![nav]));
             }
         }
diff --git a/crates/ra_ide_api/src/hover.rs b/crates/ra_ide_api/src/hover.rs
index 26f3ced70..0e9c48421 100644
--- a/crates/ra_ide_api/src/hover.rs
+++ b/crates/ra_ide_api/src/hover.rs
@@ -74,7 +74,7 @@ pub(crate) fn type_of(db: &RootDatabase, frange: FileRange) -> Cancelable<Option
         parent_fn
     ));
     let infer = function.infer(db)?;
-    let syntax_mapping = function.body_syntax_mapping(db)?;
+    let syntax_mapping = function.body_syntax_mapping(db);
     if let Some(expr) = ast::Expr::cast(node).and_then(|e| syntax_mapping.node_expr(e)) {
         Ok(Some(infer[expr].to_string()))
     } else if let Some(pat) = ast::Pat::cast(node).and_then(|p| syntax_mapping.node_pat(p)) {
diff --git a/crates/ra_ide_api/src/imp.rs b/crates/ra_ide_api/src/imp.rs
index 76cb312dd..8b2cd6e27 100644
--- a/crates/ra_ide_api/src/imp.rs
+++ b/crates/ra_ide_api/src/imp.rs
@@ -99,16 +99,16 @@ impl db::RootDatabase {
 
 impl db::RootDatabase {
     /// Returns `Vec` for the same reason as `parent_module`
-    pub(crate) fn crate_for(&self, file_id: FileId) -> Cancelable<Vec<CrateId>> {
+    pub(crate) fn crate_for(&self, file_id: FileId) -> Vec<CrateId> {
         let module = match source_binder::module_from_file_id(self, file_id) {
             Some(it) => it,
-            None => return Ok(Vec::new()),
+            None => return Vec::new(),
         };
-        let krate = match module.krate(self)? {
+        let krate = match module.krate(self) {
             Some(it) => it,
-            None => return Ok(Vec::new()),
+            None => return Vec::new(),
         };
-        Ok(vec![krate.crate_id()])
+        vec![krate.crate_id()]
     }
     pub(crate) fn find_all_refs(
         &self,
@@ -128,7 +128,7 @@ impl db::RootDatabase {
             .collect::<Vec<_>>();
         ret.extend(
             descr
-                .scopes(self)?
+                .scopes(self)
                 .find_all_refs(binding)
                 .into_iter()
                 .map(|ref_desc| (position.file_id, ref_desc.range)),
@@ -156,7 +156,7 @@ impl db::RootDatabase {
                 position.file_id,
                 name_ref.syntax(),
             ));
-            let scope = descr.scopes(db)?;
+            let scope = descr.scopes(db);
             let resolved = ctry!(scope.resolve_local_name(name_ref));
             let resolved = resolved.ptr().resolve(source_file);
             let binding = ctry!(find_node_at_offset::<ast::BindPat>(
diff --git a/crates/ra_ide_api/src/lib.rs b/crates/ra_ide_api/src/lib.rs
index e0b8410d1..0f690fc84 100644
--- a/crates/ra_ide_api/src/lib.rs
+++ b/crates/ra_ide_api/src/lib.rs
@@ -419,7 +419,7 @@ impl Analysis {
 
     /// Returns crates this file belongs too.
     pub fn crate_for(&self, file_id: FileId) -> Cancelable<Vec<CrateId>> {
-        self.with_db(|db| db.crate_for(file_id))?
+        self.with_db(|db| db.crate_for(file_id))
     }
 
     /// Returns the root file of the given crate.
diff --git a/crates/ra_ide_api/src/navigation_target.rs b/crates/ra_ide_api/src/navigation_target.rs
index 230d0f67a..21c15c0c0 100644
--- a/crates/ra_ide_api/src/navigation_target.rs
+++ b/crates/ra_ide_api/src/navigation_target.rs
@@ -1,4 +1,4 @@
-use ra_db::{FileId, Cancelable};
+use ra_db::FileId;
 use ra_syntax::{
     SyntaxNode, AstNode, SmolStr, TextRange, ast,
     SyntaxKind::{self, NAME},
@@ -69,84 +69,72 @@ impl NavigationTarget {
         }
     }
 
-    pub(crate) fn from_module(
-        db: &RootDatabase,
-        module: hir::Module,
-    ) -> Cancelable<NavigationTarget> {
-        let (file_id, source) = module.definition_source(db)?;
+    pub(crate) fn from_module(db: &RootDatabase, module: hir::Module) -> NavigationTarget {
+        let (file_id, source) = module.definition_source(db);
         let name = module
-            .name(db)?
+            .name(db)
             .map(|it| it.to_string().into())
             .unwrap_or_default();
-        let res = match source {
+        match source {
             ModuleSource::SourceFile(node) => {
                 NavigationTarget::from_syntax(file_id, name, None, node.syntax())
             }
             ModuleSource::Module(node) => {
                 NavigationTarget::from_syntax(file_id, name, None, node.syntax())
             }
-        };
-        Ok(res)
+        }
     }
 
-    pub(crate) fn from_module_to_decl(
-        db: &RootDatabase,
-        module: hir::Module,
-    ) -> Cancelable<NavigationTarget> {
+    pub(crate) fn from_module_to_decl(db: &RootDatabase, module: hir::Module) -> NavigationTarget {
         let name = module
-            .name(db)?
+            .name(db)
             .map(|it| it.to_string().into())
             .unwrap_or_default();
-        if let Some((file_id, source)) = module.declaration_source(db)? {
-            return Ok(NavigationTarget::from_syntax(
-                file_id,
-                name,
-                None,
-                source.syntax(),
-            ));
+        if let Some((file_id, source)) = module.declaration_source(db) {
+            return NavigationTarget::from_syntax(file_id, name, None, source.syntax());
         }
         NavigationTarget::from_module(db, module)
     }
 
     // TODO once Def::Item is gone, this should be able to always return a NavigationTarget
-    pub(crate) fn from_def(db: &RootDatabase, def: Def) -> Cancelable<Option<NavigationTarget>> {
+    pub(crate) fn from_def(db: &RootDatabase, def: Def) -> Option<NavigationTarget> {
         let res = match def {
             Def::Struct(s) => {
-                let (file_id, node) = s.source(db)?;
+                let (file_id, node) = s.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::Enum(e) => {
-                let (file_id, node) = e.source(db)?;
+                let (file_id, node) = e.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::EnumVariant(ev) => {
-                let (file_id, node) = ev.source(db)?;
+                let (file_id, node) = ev.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::Function(f) => {
-                let (file_id, node) = f.source(db)?;
+                let (file_id, node) = f.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::Trait(f) => {
-                let (file_id, node) = f.source(db)?;
+                let (file_id, node) = f.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::Type(f) => {
-                let (file_id, node) = f.source(db)?;
+                let (file_id, node) = f.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::Static(f) => {
-                let (file_id, node) = f.source(db)?;
+                let (file_id, node) = f.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
             Def::Const(f) => {
-                let (file_id, node) = f.source(db)?;
+                let (file_id, node) = f.source(db);
                 NavigationTarget::from_named(file_id.original_file(db), &*node)
             }
-            Def::Module(m) => NavigationTarget::from_module(db, m)?,
-            Def::Item => return Ok(None),
+            Def::Module(m) => NavigationTarget::from_module(db, m),
+            Def::Item => return None,
         };
-        Ok(Some(res))
+        Some(res)
     }
 
     #[cfg(test)]
diff --git a/crates/ra_ide_api/src/parent_module.rs b/crates/ra_ide_api/src/parent_module.rs
index 451304739..379b3f3a4 100644
--- a/crates/ra_ide_api/src/parent_module.rs
+++ b/crates/ra_ide_api/src/parent_module.rs
@@ -12,7 +12,7 @@ pub(crate) fn parent_module(
         None => return Ok(Vec::new()),
         Some(it) => it,
     };
-    let nav = NavigationTarget::from_module_to_decl(db, module)?;
+    let nav = NavigationTarget::from_module_to_decl(db, module);
     Ok(vec![nav])
 }
 
diff --git a/crates/ra_ide_api/src/runnables.rs b/crates/ra_ide_api/src/runnables.rs
index 9fa0f79a6..a3207fdd2 100644
--- a/crates/ra_ide_api/src/runnables.rs
+++ b/crates/ra_ide_api/src/runnables.rs
@@ -80,11 +80,9 @@ fn runnable_mod(db: &RootDatabase, file_id: FileId, module: &ast::Module) -> Opt
     // FIXME: thread cancellation instead of `.ok`ing
     let path = module
         .path_to_root(db)
-        .ok()?
         .into_iter()
         .rev()
-        .filter_map(|it| it.name(db).ok())
-        .filter_map(|it| it)
+        .filter_map(|it| it.name(db))
         .join("::");
     Some(Runnable {
         range,