From 3b06faad26fdb1485c542970374ff8bbcb0e01c4 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Mon, 9 Sep 2019 22:10:58 +0200
Subject: Make closures impl closure traits

---
 crates/ra_hir/src/ty/traits.rs | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

(limited to 'crates/ra_hir/src/ty/traits.rs')

diff --git a/crates/ra_hir/src/ty/traits.rs b/crates/ra_hir/src/ty/traits.rs
index c0c132809..8e256341d 100644
--- a/crates/ra_hir/src/ty/traits.rs
+++ b/crates/ra_hir/src/ty/traits.rs
@@ -9,7 +9,7 @@ use ra_prof::profile;
 use rustc_hash::FxHashSet;
 
 use super::{Canonical, GenericPredicate, HirDisplay, ProjectionTy, TraitRef, Ty, TypeWalk};
-use crate::{db::HirDatabase, Crate, ImplBlock, Trait};
+use crate::{db::HirDatabase, expr::ExprId, Crate, DefWithBody, ImplBlock, Trait};
 
 use self::chalk::{from_chalk, ToChalk};
 
@@ -252,3 +252,37 @@ pub enum Guidance {
     /// There's no useful information to feed back to type inference
     Unknown,
 }
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum FnTrait {
+    FnOnce,
+    FnMut,
+    Fn,
+}
+
+impl FnTrait {
+    fn lang_item_name(self) -> &'static str {
+        match self {
+            FnTrait::FnOnce => "fn_once",
+            FnTrait::FnMut => "fn_mut",
+            FnTrait::Fn => "fn",
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct ClosureFnTraitImplData {
+    def: DefWithBody,
+    expr: ExprId,
+    fn_trait: FnTrait,
+}
+
+/// An impl. Usually this comes from an impl block, but some built-in types get
+/// synthetic impls.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum Impl {
+    /// A normal impl from an impl block.
+    ImplBlock(ImplBlock),
+    /// Closure types implement the Fn traits synthetically.
+    ClosureFnTraitImpl(ClosureFnTraitImplData),
+}
-- 
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