From fcec76bde4026afcb47ef814aeccfd8cc1f1b28f Mon Sep 17 00:00:00 2001
From: LingMan <LingMan@users.noreply.github.com>
Date: Mon, 12 Oct 2020 23:51:35 +0200
Subject: [PATCH] Simplify a nested bool match

Logically this first eliminates the innermost match by merging the patterns.
Then, in a second step, turns the newly innermost match into a `matches!` call.
---
 compiler/rustc_ast_pretty/src/pprust/state.rs | 25 ++++++-------------
 1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index 9aa066370bb5b..969ff522f6142 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -156,24 +156,13 @@ fn tt_prepend_space(tt: &TokenTree, prev: &TokenTree) -> bool {
         }
     }
     match tt {
-        TokenTree::Token(token) => match token.kind {
-            token::Comma => false,
-            _ => true,
-        },
-        TokenTree::Delimited(_, DelimToken::Paren, _) => match prev {
-            TokenTree::Token(token) => match token.kind {
-                token::Ident(_, _) => false,
-                _ => true,
-            },
-            _ => true,
-        },
-        TokenTree::Delimited(_, DelimToken::Bracket, _) => match prev {
-            TokenTree::Token(token) => match token.kind {
-                token::Pound => false,
-                _ => true,
-            },
-            _ => true,
-        },
+        TokenTree::Token(token) => token.kind != token::Comma,
+        TokenTree::Delimited(_, DelimToken::Paren, _) => {
+            !matches!(prev, TokenTree::Token(Token { kind: token::Ident(..), .. }))
+        }
+        TokenTree::Delimited(_, DelimToken::Bracket, _) => {
+            !matches!(prev, TokenTree::Token(Token { kind: token::Pound, .. }))
+        }
         TokenTree::Delimited(..) => true,
     }
 }