23 files changed, 69 insertions, 112 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 57cfde978..23c9e2543 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -944,6 +944,7 @@ dependencies = [
 name = "ra_hir"
 version = "0.1.0"
 dependencies = [
+ "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "ra_db 0.1.0",
  "ra_hir_def 0.1.0",
@@ -957,6 +958,7 @@ dependencies = [
 name = "ra_hir_def"
 version = "0.1.0"
 dependencies = [
+ "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "insta 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "once_cell 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -976,6 +978,7 @@ dependencies = [
 name = "ra_hir_expand"
 version = "0.1.0"
 dependencies = [
+ "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "ra_arena 0.1.0",
  "ra_db 0.1.0",
@@ -1012,6 +1015,7 @@ dependencies = [
 name = "ra_ide"
 version = "0.1.0"
 dependencies = [
+ "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "format-buf 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fst 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "insta 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index e79361e7c..6ca9cc2e7 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -10,6 +10,7 @@ doctest = false
 [dependencies]
 log = "0.4.5"
 rustc-hash = "1.0"
+either = "1.5"
 
 ra_syntax = { path = "../ra_syntax" }
 ra_db = { path = "../ra_db" }
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index dddac915b..5877afefa 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -4,6 +4,7 @@ pub(crate) mod src;
 
 use std::sync::Arc;
 
+use either::Either;
 use hir_def::{
     adt::VariantData,
     body::{Body, BodySourceMap},
@@ -30,7 +31,7 @@ use crate::{
     db::{DefDatabase, HirDatabase},
     ty::display::HirFormatter,
     ty::{self, InEnvironment, InferenceResult, TraitEnvironment, Ty, TyDefId, TypeCtor, TypeWalk},
-    CallableDef, Either, HirDisplay, InFile, Name,
+    CallableDef, HirDisplay, InFile, Name,
 };
 
 /// hir::Crate describes a single crate. It's the main interface with which
@@ -905,7 +906,9 @@ impl Local {
         let (_body, source_map) = db.body_with_source_map(self.parent.into());
         let src = source_map.pat_syntax(self.pat_id).unwrap(); // Hmm...
         let root = src.file_syntax(db);
-        src.map(|ast| ast.map(|it| it.cast().unwrap().to_node(&root), |it| it.to_node(&root)))
+        src.map(|ast| {
+            ast.map_left(|it| it.cast().unwrap().to_node(&root)).map_right(|it| it.to_node(&root))
+        })
     }
 }
 
diff --git a/crates/ra_hir/src/code_model/src.rs b/crates/ra_hir/src/code_model/src.rs
index 2cf210349..36cfbc8f1 100644
--- a/crates/ra_hir/src/code_model/src.rs
+++ b/crates/ra_hir/src/code_model/src.rs
@@ -1,10 +1,10 @@
 //! FIXME: write short doc here
 
+use either::Either;
 use hir_def::{
     src::{HasChildSource, HasSource as _},
     AstItemDef, Lookup, VariantId,
 };
-use hir_expand::either::Either;
 use ra_syntax::ast;
 
 use crate::{
@@ -27,8 +27,8 @@ impl Module {
         let def_map = db.crate_def_map(self.id.krate);
         let src = def_map[self.id.local_id].definition_source(db);
         src.map(|it| match it {
-            Either::A(it) => ModuleSource::SourceFile(it),
-            Either::B(it) => ModuleSource::Module(it),
+            Either::Left(it) => ModuleSource::SourceFile(it),
+            Either::Right(it) => ModuleSource::Module(it),
         })
     }
 
@@ -46,8 +46,8 @@ impl HasSource for StructField {
         let var = VariantId::from(self.parent);
         let src = var.child_source(db);
         src.map(|it| match it[self.id].clone() {
-            Either::A(it) => FieldSource::Pos(it),
-            Either::B(it) => FieldSource::Named(it),
+            Either::Left(it) => FieldSource::Pos(it),
+            Either::Right(it) => FieldSource::Named(it),
         })
     }
 }
@@ -126,6 +126,6 @@ impl HasSource for Import {
         let (_, source_map) = db.raw_items_with_source_map(src.file_id);
         let root = db.parse_or_expand(src.file_id).unwrap();
         let ptr = source_map.get(self.id);
-        src.with_value(ptr.map(|it| it.to_node(&root), |it| it.to_node(&root)))
+        src.with_value(ptr.map_left(|it| it.to_node(&root)).map_right(|it| it.to_node(&root)))
     }
 }
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 88d2f6e02..853760cb1 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -63,5 +63,5 @@ pub use hir_def::{
     type_ref::Mutability,
 };
 pub use hir_expand::{
-    either::Either, name::Name, HirFileId, InFile, MacroCallId, MacroCallLoc, MacroDefId, MacroFile,
+    name::Name, HirFileId, InFile, MacroCallId, MacroCallLoc, MacroDefId, MacroFile,
 };
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index 0df7a7cb4..28d41b647 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -7,6 +7,7 @@
 //! purely for "IDE needs".
 use std::sync::Arc;
 
+use either::Either;
 use hir_def::{
     body::{
         scope::{ExprScopes, ScopeId},
@@ -33,8 +34,8 @@ use crate::{
         method_resolution::{self, implements_trait},
         InEnvironment, TraitEnvironment, Ty,
     },
-    Adt, AssocItem, Const, DefWithBody, Either, Enum, EnumVariant, FromSource, Function,
-    GenericParam, Local, MacroDef, Name, Path, ScopeDef, Static, Struct, Trait, Type, TypeAlias,
+    Adt, AssocItem, Const, DefWithBody, Enum, EnumVariant, FromSource, Function, GenericParam,
+    Local, MacroDef, Name, Path, ScopeDef, Static, Struct, Trait, Type, TypeAlias,
 };
 
 fn try_get_resolver_for_node(db: &impl HirDatabase, node: InFile<&SyntaxNode>) -> Option<Resolver> {
@@ -349,7 +350,7 @@ impl SourceAnalyzer {
     // should switch to general reference search infra there.
     pub fn find_all_refs(&self, pat: &ast::BindPat) -> Vec<ReferenceDescriptor> {
         let fn_def = pat.syntax().ancestors().find_map(ast::FnDef::cast).unwrap();
-        let ptr = Either::A(AstPtr::new(&ast::Pat::from(pat.clone())));
+        let ptr = Either::Left(AstPtr::new(&ast::Pat::from(pat.clone())));
         fn_def
             .syntax()
             .descendants()
diff --git a/crates/ra_hir_def/Cargo.toml b/crates/ra_hir_def/Cargo.toml
index 7e65f4c1d..cf3a446fc 100644
--- a/crates/ra_hir_def/Cargo.toml
+++ b/crates/ra_hir_def/Cargo.toml
@@ -11,6 +11,7 @@ doctest = false
 log = "0.4.5"
 once_cell = "1.0.1"
 rustc-hash = "1.0"
+either = "1.5"
 
 ra_arena = { path = "../ra_arena" }
 ra_db = { path = "../ra_db" }
diff --git a/crates/ra_hir_def/src/adt.rs b/crates/ra_hir_def/src/adt.rs
index 9ab829aab..db3e63ef8 100644
--- a/crates/ra_hir_def/src/adt.rs
+++ b/crates/ra_hir_def/src/adt.rs
@@ -2,8 +2,8 @@
 
 use std::sync::Arc;
 
+use either::Either;
 use hir_expand::{
-    either::Either,
     name::{AsName, Name},
     InFile,
 };
@@ -184,7 +184,7 @@ fn lower_struct(
         ast::StructKind::Tuple(fl) => {
             for (i, fd) in fl.fields().enumerate() {
                 trace.alloc(
-                    || Either::A(fd.clone()),
+                    || Either::Left(fd.clone()),
                     || StructFieldData {
                         name: Name::new_tuple_field(i),
                         type_ref: TypeRef::from_ast_opt(fd.type_ref()),
@@ -196,7 +196,7 @@ fn lower_struct(
         ast::StructKind::Record(fl) => {
             for fd in fl.fields() {
                 trace.alloc(
-                    || Either::B(fd.clone()),
+                    || Either::Right(fd.clone()),
                     || StructFieldData {
                         name: fd.name().map(|n| n.as_name()).unwrap_or_else(Name::missing),
                         type_ref: TypeRef::from_ast_opt(fd.ascribed_type()),
diff --git a/crates/ra_hir_def/src/attr.rs b/crates/ra_hir_def/src/attr.rs
index bc7ade921..7f9a6e7ca 100644
--- a/crates/ra_hir_def/src/attr.rs
+++ b/crates/ra_hir_def/src/attr.rs
@@ -2,7 +2,8 @@
 
 use std::{ops, sync::Arc};
 
-use hir_expand::{either::Either, hygiene::Hygiene, AstId, InFile};
+use either::Either;
+use hir_expand::{hygiene::Hygiene, AstId, InFile};
 use mbe::ast_to_token_tree;
 use ra_syntax::{
     ast::{self, AstNode, AttrsOwner},
@@ -45,8 +46,8 @@ impl Attrs {
             AttrDefId::StructFieldId(it) => {
                 let src = it.parent.child_source(db);
                 match &src.value[it.local_id] {
-                    Either::A(_tuple) => Attrs::default(),
-                    Either::B(record) => Attrs::from_attrs_owner(db, src.with_value(record)),
+                    Either::Left(_tuple) => Attrs::default(),
+                    Either::Right(record) => Attrs::from_attrs_owner(db, src.with_value(record)),
                 }
             }
             AttrDefId::EnumVariantId(var_id) => {
diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 239f35229..ef1816836 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -5,9 +5,8 @@ pub mod scope;
 
 use std::{ops::Index, sync::Arc};
 
-use hir_expand::{
-    either::Either, hygiene::Hygiene, AstId, HirFileId, InFile, MacroDefId, MacroFileKind,
-};
+use either::Either;
+use hir_expand::{hygiene::Hygiene, AstId, HirFileId, InFile, MacroDefId, MacroFileKind};
 use ra_arena::{map::ArenaMap, Arena};
 use ra_syntax::{ast, AstNode, AstPtr};
 use rustc_hash::FxHashMap;
@@ -210,7 +209,7 @@ impl BodySourceMap {
     }
 
     pub fn node_expr(&self, node: InFile<&ast::Expr>) -> Option<ExprId> {
-        let src = node.map(|it| Either::A(AstPtr::new(it)));
+        let src = node.map(|it| Either::Left(AstPtr::new(it)));
         self.expr_map.get(&src).cloned()
     }
 
@@ -219,7 +218,7 @@ impl BodySourceMap {
     }
 
     pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
-        let src = node.map(|it| Either::A(AstPtr::new(it)));
+        let src = node.map(|it| Either::Left(AstPtr::new(it)));
         self.pat_map.get(&src).cloned()
     }
 
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index be1eaa523..71c08f024 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -1,10 +1,8 @@
 //! Transforms `ast::Expr` into an equivalent `hir_def::expr::Expr`
 //! representation.
 
-use hir_expand::{
-    either::Either,
-    name::{self, AsName, Name},
-};
+use either::Either;
+use hir_expand::name::{self, AsName, Name};
 use ra_arena::Arena;
 use ra_syntax::{
     ast::{
@@ -74,7 +72,7 @@ where
                         mode: BindingAnnotation::Unannotated,
                         subpat: None,
                     },
-                    Either::B(ptr),
+                    Either::Right(ptr),
                 );
                 self.body.params.push(param_pat);
             }
@@ -94,7 +92,7 @@ where
     }
 
     fn alloc_expr(&mut self, expr: Expr, ptr: AstPtr<ast::Expr>) -> ExprId {
-        let ptr = Either::A(ptr);
+        let ptr = Either::Left(ptr);
         let id = self.body.exprs.alloc(expr);
         let src = self.expander.to_source(ptr);
         self.source_map.expr_map.insert(src, id);
@@ -107,7 +105,7 @@ where
         self.body.exprs.alloc(expr)
     }
     fn alloc_expr_field_shorthand(&mut self, expr: Expr, ptr: AstPtr<ast::RecordField>) -> ExprId {
-        let ptr = Either::B(ptr);
+        let ptr = Either::Right(ptr);
         let id = self.body.exprs.alloc(expr);
         let src = self.expander.to_source(ptr);
         self.source_map.expr_map.insert(src, id);
@@ -277,7 +275,7 @@ where
             ast::Expr::ParenExpr(e) => {
                 let inner = self.collect_expr_opt(e.expr());
                 // make the paren expr point to the inner expression as well
-                let src = self.expander.to_source(Either::A(syntax_ptr));
+                let src = self.expander.to_source(Either::Left(syntax_ptr));
                 self.source_map.expr_map.insert(src, inner);
                 inner
             }
@@ -550,7 +548,7 @@ where
             ast::Pat::SlicePat(_) | ast::Pat::RangePat(_) => Pat::Missing,
         };
         let ptr = AstPtr::new(&pat);
-        self.alloc_pat(pattern, Either::A(ptr))
+        self.alloc_pat(pattern, Either::Left(ptr))
     }
 
     fn collect_pat_opt(&mut self, pat: Option<ast::Pat>) -> PatId {
diff --git a/crates/ra_hir_def/src/docs.rs b/crates/ra_hir_def/src/docs.rs
index ec944373d..3fc6d6934 100644
--- a/crates/ra_hir_def/src/docs.rs
+++ b/crates/ra_hir_def/src/docs.rs
@@ -5,7 +5,7 @@
 
 use std::sync::Arc;
 
-use hir_expand::either::Either;
+use either::Either;
 use ra_syntax::ast;
 
 use crate::{
@@ -46,8 +46,8 @@ impl Documentation {
             AttrDefId::StructFieldId(it) => {
                 let src = it.parent.child_source(db);
                 match &src.value[it.local_id] {
-                    Either::A(_tuple) => None,
-                    Either::B(record) => docs_from_ast(record),
+                    Either::Left(_tuple) => None,
+                    Either::Right(record) => docs_from_ast(record),
                 }
             }
             AttrDefId::AdtId(it) => match it {
diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index 3e1521870..faf3566f4 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -57,9 +57,9 @@ mod tests;
 
 use std::sync::Arc;
 
+use either::Either;
 use hir_expand::{
-    ast_id_map::FileAstId, diagnostics::DiagnosticSink, either::Either, name::Name, InFile,
-    MacroDefId,
+    ast_id_map::FileAstId, diagnostics::DiagnosticSink, name::Name, InFile, MacroDefId,
 };
 use once_cell::sync::Lazy;
 use ra_arena::Arena;
@@ -287,10 +287,10 @@ impl ModuleData {
     ) -> InFile<Either<ast::SourceFile, ast::Module>> {
         if let Some(file_id) = self.definition {
             let sf = db.parse(file_id).tree();
-            return InFile::new(file_id.into(), Either::A(sf));
+            return InFile::new(file_id.into(), Either::Left(sf));
         }
         let decl = self.declaration.unwrap();
-        InFile::new(decl.file_id, Either::B(decl.to_node(db)))
+        InFile::new(decl.file_id, Either::Right(decl.to_node(db)))
     }
 
     /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
diff --git a/crates/ra_hir_def/src/nameres/raw.rs b/crates/ra_hir_def/src/nameres/raw.rs
index 5196b67ca..de4e706c2 100644
--- a/crates/ra_hir_def/src/nameres/raw.rs
+++ b/crates/ra_hir_def/src/nameres/raw.rs
@@ -7,10 +7,10 @@
 
 use std::{ops::Index, sync::Arc};
 
+use either::Either;
 use hir_expand::{
     ast_id_map::AstIdMap,
     db::AstDatabase,
-    either::Either,
     hygiene::Hygiene,
     name::{AsName, Name},
 };
@@ -324,7 +324,7 @@ impl RawItemsCollector {
                     is_extern_crate: false,
                     is_macro_use: false,
                 };
-                buf.push((import_data, Either::A(AstPtr::new(use_tree))));
+                buf.push((import_data, Either::Left(AstPtr::new(use_tree))));
             },
         );
         for (import_data, ptr) in buf {
@@ -355,7 +355,7 @@ impl RawItemsCollector {
                 current_module,
                 attrs,
                 import_data,
-                Either::B(AstPtr::new(&extern_crate)),
+                Either::Right(AstPtr::new(&extern_crate)),
             );
         }
     }
diff --git a/crates/ra_hir_def/src/path.rs b/crates/ra_hir_def/src/path.rs
index ff252fe44..3030dcdf6 100644
--- a/crates/ra_hir_def/src/path.rs
+++ b/crates/ra_hir_def/src/path.rs
@@ -2,8 +2,8 @@
 
 use std::{iter, sync::Arc};
 
+use either::Either;
 use hir_expand::{
-    either::Either,
     hygiene::Hygiene,
     name::{self, AsName, Name},
 };
@@ -111,7 +111,7 @@ impl Path {
                 ast::PathSegmentKind::Name(name_ref) => {
                     // FIXME: this should just return name
                     match hygiene.name_ref_to_name(name_ref) {
-                        Either::A(name) => {
+                        Either::Left(name) => {
                             let args = segment
                                 .type_arg_list()
                                 .and_then(GenericArgs::from_ast)
@@ -125,7 +125,7 @@ impl Path {
                             let segment = PathSegment { name, args_and_bindings: args };
                             segments.push(segment);
                         }
-                        Either::B(crate_id) => {
+                        Either::Right(crate_id) => {
                             kind = PathKind::DollarCrate(crate_id);
                             break;
                         }
@@ -347,7 +347,7 @@ fn convert_path(prefix: Option<Path>, path: ast::Path, hygiene: &Hygiene) -> Opt
     let res = match segment.kind()? {
         ast::PathSegmentKind::Name(name_ref) => {
             match hygiene.name_ref_to_name(name_ref) {
-                Either::A(name) => {
+                Either::Left(name) => {
                     // no type args in use
                     let mut res = prefix.unwrap_or_else(|| Path {
                         kind: PathKind::Plain,
@@ -359,7 +359,7 @@ fn convert_path(prefix: Option<Path>, path: ast::Path, hygiene: &Hygiene) -> Opt
                     });
                     res
                 }
-                Either::B(crate_id) => {
+                Either::Right(crate_id) => {
                     return Some(Path::from_simple_segments(
                         PathKind::DollarCrate(crate_id),
                         iter::empty(),
diff --git a/crates/ra_hir_expand/Cargo.toml b/crates/ra_hir_expand/Cargo.toml
index c60152a79..3ae4376dc 100644
--- a/crates/ra_hir_expand/Cargo.toml
+++ b/crates/ra_hir_expand/Cargo.toml
@@ -9,6 +9,7 @@ doctest = false
 
 [dependencies]
 log = "0.4.5"
+either = "1.5"
 
 ra_arena = { path = "../ra_arena" }
 ra_db = { path = "../ra_db" }
diff --git a/crates/ra_hir_expand/src/either.rs b/crates/ra_hir_expand/src/either.rs
deleted file mode 100644
index 83583ef8b..000000000
--- a/crates/ra_hir_expand/src/either.rs
+++ /dev/null
@@ -1,54 +0,0 @@
-//! FIXME: write short doc here
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub enum Either<A, B> {
-    A(A),
-    B(B),
-}
-
-impl<A, B> Either<A, B> {
-    pub fn either<R, F1, F2>(self, f1: F1, f2: F2) -> R
-    where
-        F1: FnOnce(A) -> R,
-        F2: FnOnce(B) -> R,
-    {
-        match self {
-            Either::A(a) => f1(a),
-            Either::B(b) => f2(b),
-        }
-    }
-    pub fn map<U, V, F1, F2>(self, f1: F1, f2: F2) -> Either<U, V>
-    where
-        F1: FnOnce(A) -> U,
-        F2: FnOnce(B) -> V,
-    {
-        match self {
-            Either::A(a) => Either::A(f1(a)),
-            Either::B(b) => Either::B(f2(b)),
-        }
-    }
-    pub fn map_a<U, F>(self, f: F) -> Either<U, B>
-    where
-        F: FnOnce(A) -> U,
-    {
-        self.map(f, |it| it)
-    }
-    pub fn a(self) -> Option<A> {
-        match self {
-            Either::A(it) => Some(it),
-            Either::B(_) => None,
-        }
-    }
-    pub fn b(self) -> Option<B> {
-        match self {
-            Either::A(_) => None,
-            Either::B(it) => Some(it),
-        }
-    }
-    pub fn as_ref(&self) -> Either<&A, &B> {
-        match self {
-            Either::A(it) => Either::A(it),
-            Either::B(it) => Either::B(it),
-        }
-    }
-}
diff --git a/crates/ra_hir_expand/src/hygiene.rs b/crates/ra_hir_expand/src/hygiene.rs
index 379562a2c..64c8b06c6 100644
--- a/crates/ra_hir_expand/src/hygiene.rs
+++ b/crates/ra_hir_expand/src/hygiene.rs
@@ -2,12 +2,12 @@
 //!
 //! Specifically, `ast` + `Hygiene` allows you to create a `Name`. Note that, at
 //! this moment, this is horribly incomplete and handles only `$crate`.
+use either::Either;
 use ra_db::CrateId;
 use ra_syntax::ast;
 
 use crate::{
     db::AstDatabase,
-    either::Either,
     name::{AsName, Name},
     HirFileId, HirFileIdRepr, MacroDefKind,
 };
@@ -41,9 +41,9 @@ impl Hygiene {
     pub fn name_ref_to_name(&self, name_ref: ast::NameRef) -> Either<Name, CrateId> {
         if let Some(def_crate) = self.def_crate {
             if name_ref.text() == "$crate" {
-                return Either::B(def_crate);
+                return Either::Right(def_crate);
             }
         }
-        Either::A(name_ref.as_name())
+        Either::Left(name_ref.as_name())
     }
 }
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index fb88d2ac2..3be9bdf86 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -6,7 +6,6 @@
 
 pub mod db;
 pub mod ast_id_map;
-pub mod either;
 pub mod name;
 pub mod hygiene;
 pub mod diagnostics;
diff --git a/crates/ra_hir_ty/src/expr.rs b/crates/ra_hir_ty/src/expr.rs
index 5c65f9370..d2bd64e5c 100644
--- a/crates/ra_hir_ty/src/expr.rs
+++ b/crates/ra_hir_ty/src/expr.rs
@@ -97,7 +97,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
         let (_, source_map) = db.body_with_source_map(self.func.into());
 
         if let Some(source_ptr) = source_map.expr_syntax(id) {
-            if let Some(expr) = source_ptr.value.a() {
+            if let Some(expr) = source_ptr.value.left() {
                 let root = source_ptr.file_syntax(db);
                 if let ast::Expr::RecordLit(record_lit) = expr.to_node(&root) {
                     if let Some(field_list) = record_lit.record_field_list() {
@@ -142,7 +142,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             let (_, source_map) = db.body_with_source_map(self.func.into());
 
             if let Some(source_ptr) = source_map.expr_syntax(id) {
-                if let Some(expr) = source_ptr.value.a() {
+                if let Some(expr) = source_ptr.value.left() {
                     self.sink.push(MissingOkInTailExpr { file: source_ptr.file_id, expr });
                 }
             }
diff --git a/crates/ra_ide/Cargo.toml b/crates/ra_ide/Cargo.toml
index e6383dd35..e3439ae31 100644
--- a/crates/ra_ide/Cargo.toml
+++ b/crates/ra_ide/Cargo.toml
@@ -11,6 +11,7 @@ doctest = false
 wasm = []
 
 [dependencies]
+either = "1.5"
 format-buf = "1.0.0"
 itertools = "0.8.0"
 join_to_string = "0.1.3"
diff --git a/crates/ra_ide/src/completion/complete_path.rs b/crates/ra_ide/src/completion/complete_path.rs
index 89e0009a1..28f94e0a7 100644
--- a/crates/ra_ide/src/completion/complete_path.rs
+++ b/crates/ra_ide/src/completion/complete_path.rs
@@ -1,6 +1,7 @@
 //! FIXME: write short doc here
 
-use hir::{Adt, Either, HasSource, PathResolution};
+use either::Either;
+use hir::{Adt, HasSource, PathResolution};
 use ra_syntax::AstNode;
 use test_utils::tested_by;
 
@@ -27,7 +28,7 @@ pub(super) fn complete_path(acc: &mut Completions, ctx: &CompletionContext) {
                 }
                 if Some(module) == ctx.module {
                     if let Some(import) = import {
-                        if let Either::A(use_tree) = import.source(ctx.db).value {
+                        if let Either::Left(use_tree) = import.source(ctx.db).value {
                             if use_tree.syntax().text_range().contains_inclusive(ctx.offset) {
                                 // for `use self::foo<|>`, don't suggest `foo` as a completion
                                 tested_by!(dont_complete_current_use);
diff --git a/crates/ra_ide/src/display/navigation_target.rs b/crates/ra_ide/src/display/navigation_target.rs
index 61dca14ac..f920d3db6 100644
--- a/crates/ra_ide/src/display/navigation_target.rs
+++ b/crates/ra_ide/src/display/navigation_target.rs
@@ -1,6 +1,7 @@
 //! FIXME: write short doc here
 
-use hir::{AssocItem, Either, FieldSource, HasSource, InFile, ModuleSource};
+use either::Either;
+use hir::{AssocItem, FieldSource, HasSource, InFile, ModuleSource};
 use ra_db::{FileId, SourceDatabase};
 use ra_syntax::{
     ast::{self, DocCommentsOwner, NameOwner},
@@ -342,10 +343,10 @@ impl ToNav for hir::Local {
     fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
         let src = self.source(db);
         let (full_range, focus_range) = match src.value {
-            Either::A(it) => {
+            Either::Left(it) => {
                 (it.syntax().text_range(), it.name().map(|it| it.syntax().text_range()))
             }
-            Either::B(it) => (it.syntax().text_range(), Some(it.self_kw_token().text_range())),
+            Either::Right(it) => (it.syntax().text_range(), Some(it.self_kw_token().text_range())),
         };
         let name = match self.name(db) {
             Some(it) => it.to_string().into(),