pprust: Do not print spaces before some tokens

src/libsyntax/print/pprust.rs

@@ -152,6 +152,18 @@ pub fn to_string<F>(f: F) -> String where
  printer.s.eof()
 }
 
+// This makes comma-separated lists look slightly nicer,
+// and also addresses a specific regression described in issue #63896.
+fn tt_prepend_space(tt: &TokenTree) -> bool {
+ match tt {
+ TokenTree::Token(token) => match token.kind {
+ token::Comma => false,
+ _ => true,
+ }
+ _ => true,
+ }
+}
+
 fn binop_to_string(op: BinOpToken) -> &'static str {
  match op {
  token::Plus => "+",
@@ -696,7 +708,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target=pp::Printer> + std::ops::DerefM
 
  fn print_tts(&mut self, tts: tokenstream::TokenStream, convert_dollar_crate: bool) {
  for (i, tt) in tts.into_trees().enumerate() {
- if i != 0 {
+ if i != 0 && tt_prepend_space(&tt) {
  self.space();
  }
  self.print_tt(tt, convert_dollar_crate);

src/test/pretty/attr-literals.rs

@@ -5,10 +5,10 @@
 #![feature(rustc_attrs)]
 
 fn main() {
- #![rustc_dummy("hi" , 1 , 2 , 1.012 , pi = 3.14 , bye , name ("John"))]
+ #![rustc_dummy("hi", 1, 2, 1.012, pi = 3.14, bye, name ("John"))]
  #[rustc_dummy = 8]
  fn f() { }
 
- #[rustc_dummy(1 , 2 , 3)]
+ #[rustc_dummy(1, 2, 3)]
  fn g() { }
 }

src/test/pretty/block-comment-wchar.pp

@@ -99,8 +99,5 @@
  '\u{2004}', '\u{2005}', '\u{2006}', '\u{2007}', '\u{2008}',
  '\u{2009}', '\u{200A}', '\u{2028}', '\u{2029}', '\u{202F}',
  '\u{205F}', '\u{3000}'];
- for c in &chars {
- let ws = c.is_whitespace();
- println!("{} {}" , c , ws);
- }
+ for c in &chars { let ws = c.is_whitespace(); println!("{} {}", c, ws); }
 }

src/test/pretty/delimited-token-groups.rs

@@ -5,7 +5,7 @@
 macro_rules! mac { ($ ($ tt : tt) *) => () }
 
 mac! {
- struct S { field1 : u8 , field2 : u16 , } impl Clone for S
+ struct S { field1 : u8, field2 : u16, } impl Clone for S
  {
  fn clone () -> S
  {

src/test/pretty/do1.rs

@@ -2,4 +2,4 @@
 
 fn f<F>(f: F) where F: Fn(isize) { f(10) }
 
-fn main() { f(|i| { assert_eq!(i , 10) }) }
+fn main() { f(|i| { assert_eq!(i, 10) }) }

src/test/pretty/match-block-expr.rs

@@ -2,5 +2,5 @@
 
 fn main() {
  let x = match { 5 } { 1 => 5, 2 => 6, _ => 7, };
- assert_eq!(x , 7);
+ assert_eq!(x, 7);
 }

src/test/ui/macros/macro-first-set.rs

@@ -25,7 +25,7 @@ macro_rules! foo_26444 {
 }
 
 fn test_26444() {
- assert_eq!("a , b , c , d , e", foo_26444!(a, b; c; d, e));
+ assert_eq!("a, b, c, d, e", foo_26444!(a, b; c; d, e));
  assert_eq!("f", foo_26444!(; f ;));
 }
 

src/test/ui/proc-macro/auxiliary/attr-stmt-expr-rpass.rs

@@ -17,7 +17,7 @@ pub fn expect_let(attr: TokenStream, item: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn expect_print_stmt(attr: TokenStream, item: TokenStream) -> TokenStream {
  assert!(attr.to_string().is_empty());
- assert_eq!(item.to_string(), "println!(\"{}\" , string);");
+ assert_eq!(item.to_string(), "println!(\"{}\", string);");
  item
 }
 
@@ -31,7 +31,7 @@ pub fn expect_expr(attr: TokenStream, item: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn expect_print_expr(attr: TokenStream, item: TokenStream) -> TokenStream {
  assert!(attr.to_string().is_empty());
- assert_eq!(item.to_string(), "println!(\"{}\" , string)");
+ assert_eq!(item.to_string(), "println!(\"{}\", string)");
  item
 }
 

src/test/ui/proc-macro/auxiliary/attr-stmt-expr.rs

@@ -17,7 +17,7 @@ pub fn expect_let(attr: TokenStream, item: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn expect_print_stmt(attr: TokenStream, item: TokenStream) -> TokenStream {
  assert!(attr.to_string().is_empty());
- assert_eq!(item.to_string(), "println!(\"{}\" , string);");
+ assert_eq!(item.to_string(), "println!(\"{}\", string);");
  item
 }
 
@@ -31,7 +31,7 @@ pub fn expect_expr(attr: TokenStream, item: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn expect_print_expr(attr: TokenStream, item: TokenStream) -> TokenStream {
  assert!(attr.to_string().is_empty());
- assert_eq!(item.to_string(), "println!(\"{}\" , string)");
+ assert_eq!(item.to_string(), "println!(\"{}\", string)");
  item
 }