11 files changed, 67 insertions, 106 deletions

diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index ba7b39a19..512676c99 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -15,6 +15,7 @@ arrayvec = "0.5.1"
 
 itertools = "0.9.0"
 
+stdx = { path = "../stdx" }
 ra_syntax = { path = "../ra_syntax" }
 ra_db = { path = "../ra_db" }
 ra_prof = { path = "../ra_prof" }
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 04fd335fe..9222009fe 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -38,6 +38,7 @@ use ra_syntax::{
     AstNode,
 };
 use rustc_hash::FxHashSet;
+use stdx::impl_from;
 
 use crate::{
     db::{DefDatabase, HirDatabase},
@@ -142,8 +143,8 @@ pub enum ModuleDef {
     TypeAlias(TypeAlias),
     BuiltinType(BuiltinType),
 }
-impl_froms!(
-    ModuleDef: Module,
+impl_from!(
+    Module,
     Function,
     Adt(Struct, Enum, Union),
     EnumVariant,
@@ -152,6 +153,7 @@ impl_froms!(
     Trait,
     TypeAlias,
     BuiltinType
+    for ModuleDef
 );
 
 impl ModuleDef {
@@ -541,7 +543,7 @@ pub enum Adt {
     Union(Union),
     Enum(Enum),
 }
-impl_froms!(Adt: Struct, Union, Enum);
+impl_from!(Struct, Union, Enum for Adt);
 
 impl Adt {
     pub fn has_non_default_type_params(self, db: &dyn HirDatabase) -> bool {
@@ -584,7 +586,7 @@ pub enum VariantDef {
     Union(Union),
     EnumVariant(EnumVariant),
 }
-impl_froms!(VariantDef: Struct, Union, EnumVariant);
+impl_from!(Struct, Union, EnumVariant for VariantDef);
 
 impl VariantDef {
     pub fn fields(self, db: &dyn HirDatabase) -> Vec<Field> {
@@ -627,8 +629,7 @@ pub enum DefWithBody {
     Static(Static),
     Const(Const),
 }
-
-impl_froms!(DefWithBody: Function, Const, Static);
+impl_from!(Function, Const, Static for DefWithBody);
 
 impl DefWithBody {
     pub fn module(self, db: &dyn HirDatabase) -> Module {
@@ -930,14 +931,15 @@ pub enum GenericDef {
     // consts can have type parameters from their parents (i.e. associated consts of traits)
     Const(Const),
 }
-impl_froms!(
-    GenericDef: Function,
+impl_from!(
+    Function,
     Adt(Struct, Enum, Union),
     Trait,
     TypeAlias,
     ImplDef,
     EnumVariant,
     Const
+    for GenericDef
 );
 
 impl GenericDef {
@@ -1578,8 +1580,8 @@ pub enum AttrDef {
     MacroDef(MacroDef),
 }
 
-impl_froms!(
-    AttrDef: Module,
+impl_from!(
+    Module,
     Field,
     Adt(Struct, Enum, Union),
     EnumVariant,
@@ -1589,6 +1591,7 @@ impl_froms!(
     Trait,
     TypeAlias,
     MacroDef
+    for AttrDef
 );
 
 pub trait HasAttrs {
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 3364a822f..7d9b174b4 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -19,25 +19,6 @@
 
 #![recursion_limit = "512"]
 
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident $(($($sv:ident),*))?),*$(,)?) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-            $($(
-                impl From<$sv> for $e {
-                    fn from(it: $sv) -> $e {
-                        $e::$v($v::$sv(it))
-                    }
-                }
-            )*)?
-        )*
-    }
-}
-
 mod semantics;
 pub mod db;
 mod source_analyzer;
diff --git a/crates/ra_hir/src/semantics/source_to_def.rs b/crates/ra_hir/src/semantics/source_to_def.rs
index 0e1d92fb3..42e5a1bdb 100644
--- a/crates/ra_hir/src/semantics/source_to_def.rs
+++ b/crates/ra_hir/src/semantics/source_to_def.rs
@@ -16,6 +16,7 @@ use ra_syntax::{
     match_ast, AstNode, SyntaxNode,
 };
 use rustc_hash::FxHashMap;
+use stdx::impl_from;
 
 use crate::{db::HirDatabase, InFile, MacroDefId};
 
@@ -255,8 +256,7 @@ pub(crate) enum ChildContainer {
     /// here the children generic parameters, and not, eg enum variants.
     GenericDefId(GenericDefId),
 }
-impl_froms! {
-    ChildContainer:
+impl_from! {
     DefWithBodyId,
     ModuleId,
     TraitId,
@@ -265,6 +265,7 @@ impl_froms! {
     VariantId,
     TypeAliasId,
     GenericDefId
+    for ChildContainer
 }
 
 impl ChildContainer {
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 564434ccc..b71d626c3 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -65,6 +65,7 @@ use item_tree::{
     Const, Enum, Function, Impl, ItemTreeId, ItemTreeNode, ModItem, Static, Struct, Trait,
     TypeAlias, Union,
 };
+use stdx::impl_from;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ModuleId {
@@ -223,25 +224,6 @@ pub struct TypeParamId {
 
 pub type LocalTypeParamId = Idx<generics::TypeParamData>;
 
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident $(($($sv:ident),*))?),*) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-            $($(
-                impl From<$sv> for $e {
-                    fn from(it: $sv) -> $e {
-                        $e::$v($v::$sv(it))
-                    }
-                }
-            )*)?
-        )*
-    }
-}
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum ContainerId {
     ModuleId(ModuleId),
@@ -254,7 +236,7 @@ pub enum AssocContainerId {
     ImplId(ImplId),
     TraitId(TraitId),
 }
-impl_froms!(AssocContainerId: ContainerId);
+impl_from!(ContainerId for AssocContainerId);
 
 /// A Data Type
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
@@ -263,7 +245,7 @@ pub enum AdtId {
     UnionId(UnionId),
     EnumId(EnumId),
 }
-impl_froms!(AdtId: StructId, UnionId, EnumId);
+impl_from!(StructId, UnionId, EnumId for AdtId);
 
 /// The defs which can be visible in the module.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -279,8 +261,8 @@ pub enum ModuleDefId {
     TypeAliasId(TypeAliasId),
     BuiltinType(BuiltinType),
 }
-impl_froms!(
-    ModuleDefId: ModuleId,
+impl_from!(
+    ModuleId,
     FunctionId,
     AdtId(StructId, EnumId, UnionId),
     EnumVariantId,
@@ -289,6 +271,7 @@ impl_froms!(
     TraitId,
     TypeAliasId,
     BuiltinType
+    for ModuleDefId
 );
 
 /// The defs which have a body.
@@ -299,7 +282,7 @@ pub enum DefWithBodyId {
     ConstId(ConstId),
 }
 
-impl_froms!(DefWithBodyId: FunctionId, ConstId, StaticId);
+impl_from!(FunctionId, ConstId, StaticId for DefWithBodyId);
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum AssocItemId {
@@ -311,7 +294,7 @@ pub enum AssocItemId {
 // sure that you can only turn actual assoc items into AssocItemIds. This would
 // require not implementing From, and instead having some checked way of
 // casting them, and somehow making the constructors private, which would be annoying.
-impl_froms!(AssocItemId: FunctionId, ConstId, TypeAliasId);
+impl_from!(FunctionId, ConstId, TypeAliasId for AssocItemId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
 pub enum GenericDefId {
@@ -326,14 +309,15 @@ pub enum GenericDefId {
     // consts can have type parameters from their parents (i.e. associated consts of traits)
     ConstId(ConstId),
 }
-impl_froms!(
-    GenericDefId: FunctionId,
+impl_from!(
+    FunctionId,
     AdtId(StructId, EnumId, UnionId),
     TraitId,
     TypeAliasId,
     ImplId,
     EnumVariantId,
     ConstId
+    for GenericDefId
 );
 
 impl From<AssocItemId> for GenericDefId {
@@ -361,8 +345,8 @@ pub enum AttrDefId {
     ImplId(ImplId),
 }
 
-impl_froms!(
-    AttrDefId: ModuleId,
+impl_from!(
+    ModuleId,
     FieldId,
     AdtId(StructId, EnumId, UnionId),
     EnumVariantId,
@@ -373,6 +357,7 @@ impl_froms!(
     TypeAliasId,
     MacroDefId,
     ImplId
+    for AttrDefId
 );
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -381,7 +366,7 @@ pub enum VariantId {
     StructId(StructId),
     UnionId(UnionId),
 }
-impl_froms!(VariantId: EnumVariantId, StructId, UnionId);
+impl_from!(EnumVariantId, StructId, UnionId for VariantId);
 
 trait Intern {
     type ID;
diff --git a/crates/ra_hir_ty/src/infer.rs b/crates/ra_hir_ty/src/infer.rs
index 5c56c2eb0..2ce4f65cc 100644
--- a/crates/ra_hir_ty/src/infer.rs
+++ b/crates/ra_hir_ty/src/infer.rs
@@ -18,8 +18,6 @@ use std::mem;
 use std::ops::Index;
 use std::sync::Arc;
 
-use rustc_hash::FxHashMap;
-
 use hir_def::{
     body::Body,
     data::{ConstData, FunctionData, StaticData},
@@ -35,6 +33,8 @@ use hir_expand::{diagnostics::DiagnosticSink, name::name};
 use ra_arena::map::ArenaMap;
 use ra_prof::profile;
 use ra_syntax::SmolStr;
+use rustc_hash::FxHashMap;
+use stdx::impl_from;
 
 use super::{
     primitive::{FloatTy, IntTy},
@@ -84,8 +84,7 @@ enum ExprOrPatId {
     ExprId(ExprId),
     PatId(PatId),
 }
-
-impl_froms!(ExprOrPatId: ExprId, PatId);
+impl_from!(ExprId, PatId for ExprOrPatId);
 
 /// Binding modes inferred for patterns.
 /// https://doc.rust-lang.org/reference/patterns.html#binding-modes
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index 34f0bd4ce..2652d200f 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -6,25 +6,6 @@ macro_rules! eprintln {
     ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
 }
 
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident $(($($sv:ident),*))?),*) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-            $($(
-                impl From<$sv> for $e {
-                    fn from(it: $sv) -> $e {
-                        $e::$v($v::$sv(it))
-                    }
-                }
-            )*)?
-        )*
-    }
-}
-
 mod autoderef;
 pub mod primitive;
 pub mod traits;
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index 3af8d55a1..101b8aebe 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -5,10 +5,7 @@
 //!  - Building the type for an item: This happens through the `type_for_def` query.
 //!
 //! This usually involves resolving names, collecting generic arguments etc.
-use std::iter;
-use std::sync::Arc;
-
-use smallvec::SmallVec;
+use std::{iter, sync::Arc};
 
 use hir_def::{
     adt::StructKind,
@@ -24,6 +21,8 @@ use hir_def::{
 use hir_expand::name::Name;
 use ra_arena::map::ArenaMap;
 use ra_db::CrateId;
+use smallvec::SmallVec;
+use stdx::impl_from;
 use test_utils::mark;
 
 use crate::{
@@ -1110,7 +1109,7 @@ pub enum CallableDef {
     StructId(StructId),
     EnumVariantId(EnumVariantId),
 }
-impl_froms!(CallableDef: FunctionId, StructId, EnumVariantId);
+impl_from!(FunctionId, StructId, EnumVariantId for CallableDef);
 
 impl CallableDef {
     pub fn krate(self, db: &dyn HirDatabase) -> CrateId {
@@ -1140,7 +1139,7 @@ pub enum TyDefId {
     AdtId(AdtId),
     TypeAliasId(TypeAliasId),
 }
-impl_froms!(TyDefId: BuiltinType, AdtId(StructId, EnumId, UnionId), TypeAliasId);
+impl_from!(BuiltinType, AdtId(StructId, EnumId, UnionId), TypeAliasId for TyDefId);
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum ValueTyDefId {
@@ -1150,7 +1149,7 @@ pub enum ValueTyDefId {
     ConstId(ConstId),
     StaticId(StaticId),
 }
-impl_froms!(ValueTyDefId: FunctionId, StructId, EnumVariantId, ConstId, StaticId);
+impl_from!(FunctionId, StructId, EnumVariantId, ConstId, StaticId for ValueTyDefId);
 
 /// Build the declared type of an item. This depends on the namespace; e.g. for
 /// `struct Foo(usize)`, we have two types: The type of the struct itself, and
diff --git a/crates/ra_tt/Cargo.toml b/crates/ra_tt/Cargo.toml
index f7230a9ca..b5b12e3af 100644
--- a/crates/ra_tt/Cargo.toml
+++ b/crates/ra_tt/Cargo.toml
@@ -8,6 +8,7 @@ authors = ["rust-analyzer developers"]
 doctest = false
 
 [dependencies]
+stdx = { path = "../stdx" }
 # ideally, `serde` should be enabled by `rust-analyzer`, but we enable it here
 # to reduce number of compilations
 smol_str = { version = "0.1.15", features = ["serde"] }
diff --git a/crates/ra_tt/src/lib.rs b/crates/ra_tt/src/lib.rs
index 342ddbe32..8faf1cc67 100644
--- a/crates/ra_tt/src/lib.rs
+++ b/crates/ra_tt/src/lib.rs
@@ -1,24 +1,13 @@
 //! `tt` crate defines a `TokenTree` data structure: this is the interface (both
 //! input and output) of macros. It closely mirrors `proc_macro` crate's
 //! `TokenTree`.
-
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident), *) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-        )*
-    }
-}
-
 use std::{
     fmt::{self, Debug},
     panic::RefUnwindSafe,
 };
 
+use stdx::impl_from;
+
 pub use smol_str::SmolStr;
 
 /// Represents identity of the token.
@@ -41,7 +30,7 @@ pub enum TokenTree {
     Leaf(Leaf),
     Subtree(Subtree),
 }
-impl_froms!(TokenTree: Leaf, Subtree);
+impl_from!(Leaf, Subtree for TokenTree);
 
 impl TokenTree {
     pub fn empty() -> Self {
@@ -55,7 +44,7 @@ pub enum Leaf {
     Punct(Punct),
     Ident(Ident),
 }
-impl_froms!(Leaf: Literal, Punct, Ident);
+impl_from!(Literal, Punct, Ident for Leaf);
 
 #[derive(Clone, PartialEq, Eq, Hash, Default)]
 pub struct Subtree {
diff --git a/crates/stdx/src/macros.rs b/crates/stdx/src/macros.rs
index 0f7690a67..bf298460f 100644
--- a/crates/stdx/src/macros.rs
+++ b/crates/stdx/src/macros.rs
@@ -17,3 +17,24 @@ macro_rules! format_to {
         { use ::std::fmt::Write as _; let _ = ::std::write!($buf, $lit $($arg)*); }
     };
 }
+
+// Generates `From` impls for `Enum E { Foo(Foo), Bar(Bar) }` enums
+#[macro_export]
+macro_rules! impl_from {
+    ($($variant:ident $(($($sub_variant:ident),*))?),* for $enum:ident) => {
+        $(
+            impl From<$variant> for $enum {
+                fn from(it: $variant) -> $enum {
+                    $enum::$variant(it)
+                }
+            }
+            $($(
+                impl From<$sub_variant> for $enum {
+                    fn from(it: $sub_variant) -> $enum {
+                        $enum::$variant($variant::$sub_variant(it))
+                    }
+                }
+            )*)?
+        )*
+    }
+}