From 48dec842f2306cb8a1493308f95cedacb74d0ab9 Mon Sep 17 00:00:00 2001
From: Julian Knodt <julianknodt@gmail.com>
Date: Thu, 31 Dec 2020 01:58:27 +0100
Subject: [PATCH] first pass at default values for const generics

- Adds optional default values to const generic parameters in the AST
  and HIR
- Parses these optional default values
- Adds a `const_generics_defaults` feature gate
---
 clippy_lints/src/utils/ast_utils.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/clippy_lints/src/utils/ast_utils.rs b/clippy_lints/src/utils/ast_utils.rs
index f0267e4c792..940573e4caa 100644
--- a/clippy_lints/src/utils/ast_utils.rs
+++ b/clippy_lints/src/utils/ast_utils.rs
@@ -407,6 +407,10 @@ pub fn eq_use_tree_kind(l: &UseTreeKind, r: &UseTreeKind) -> bool {
     }
 }
 
+pub fn eq_anon_const(l: &AnonConst, r: &AnonConst) -> bool {
+    eq_expr(&l.value, &r.value)
+}
+
 pub fn eq_defaultness(l: Defaultness, r: Defaultness) -> bool {
     matches!(
         (l, r),
@@ -497,7 +501,8 @@ pub fn eq_generic_param(l: &GenericParam, r: &GenericParam) -> bool {
         && match (&l.kind, &r.kind) {
             (Lifetime, Lifetime) => true,
             (Type { default: l }, Type { default: r }) => both(l, r, |l, r| eq_ty(l, r)),
-            (Const { ty: l, kw_span: _ }, Const { ty: r, kw_span: _ }) => eq_ty(l, r),
+            (Const { ty: lt, kw_span: _ , default: ld}, Const { ty: rt, kw_span: _, default: rd }) =>
+                eq_ty(lt, rt) && both(ld, rd, |ld, rd| eq_anon_const(ld, rd)),
             _ => false,
         }
         && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))