Improve token stream pretty printing.

Specifically: - No space before or after `::`, e.g. `a::b` instead of `a :: b`. - No space between `!` and `(`, e.g. `foo!()` instead of `foo! ()`. - No space between `!` and `[`, e.g. `#![...]` instead of `#! [...]`. - No space before `:`, e.g. `a: u32` instead of `a : u32`. - No space before `;`, e.g. `struct A;` instead of `struct A ;`.
rust-lang · May 24, 2022 · 20d4424 · 20d4424
1 parent b2eed72
commit 20d4424
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Showing 54 changed files with 181 additions and 179 deletions.
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -146,20 +146,29 @@ pub fn print_crate<'a>(
 /// and also addresses some specific regressions described in #63896 and #73345.
 fn tt_prepend_space(tt: &TokenTree, prev: &TokenTree) -> bool {
     if let TokenTree::Token(token) = prev {
-        if matches!(token.kind, token::Dot | token::Dollar) {
+        // No space after these tokens, e.g. `x.y`, `$e`, `a::b`
+        // (The carets point to `prev`)        ^     ^      ^^
+        if matches!(token.kind, token::Dot | token::Dollar | token::ModSep) {
             return false;
         }
         if let token::DocComment(comment_kind, ..) = token.kind {
             return comment_kind != CommentKind::Line;
         }
     }
     match tt {
-        TokenTree::Token(token) => !matches!(token.kind, token::Comma | token::Not | token::Dot),
+        // No space before these tokens, e.g. `x,`, `m!`, `x.y`, `a::b`, `s;`, `x:`
+        // (The carets point to `token`)        ^     ^     ^      ^^     ^     ^
+        TokenTree::Token(token) => !matches!(
+            token.kind,
+            token::Comma | token::Not | token::Dot | token::ModSep | token::Semi | token::Colon
+        ),
+        // No space before parentheses if preceded by these tokens, e.g. `foo(...)`, `foo!(...).
         TokenTree::Delimited(_, Delimiter::Parenthesis, _) => {
-            !matches!(prev, TokenTree::Token(Token { kind: token::Ident(..), .. }))
+            !matches!(prev, TokenTree::Token(Token { kind: token::Ident(..) | token::Not, .. }))
         }
+        // No space before brackets if preceded by these tokens, e.g. e.g. `#[...]`, `#![...]`.
         TokenTree::Delimited(_, Delimiter::Bracket, _) => {
-            !matches!(prev, TokenTree::Token(Token { kind: token::Pound, .. }))
+            !matches!(prev, TokenTree::Token(Token { kind: token::Pound | token::Not, .. }))
         }
         TokenTree::Delimited(..) => true,
     }

diff --git a/src/test/pretty/ast-stmt-expr-attr.rs b/src/test/pretty/ast-stmt-expr-attr.rs
@@ -114,11 +114,11 @@ fn syntax() {
     let _ = #[attr] continue;
     let _ = #[attr] return;
     let _ = #[attr] foo!();
-    let _ = #[attr] foo!(#! [attr]);
+    let _ = #[attr] foo!(#![attr]);
     let _ = #[attr] foo![];
-    let _ = #[attr] foo![#! [attr]];
+    let _ = #[attr] foo![#![attr]];
     let _ = #[attr] foo! {};
-    let _ = #[attr] foo! { #! [attr] };
+    let _ = #[attr] foo! { #![attr] };
     let _ = #[attr] Foo { bar: baz };
     let _ = #[attr] Foo { ..foo };
     let _ = #[attr] Foo { bar: baz, ..foo };

diff --git a/src/test/pretty/cast-lt.pp b/src/test/pretty/cast-lt.pp
@@ -8,6 +8,6 @@
 // pretty-mode:expanded
 // pp-exact:cast-lt.pp
 
-macro_rules! negative { ($e : expr) => { $e < 0 } }
+macro_rules! negative { ($e: expr) => { $e < 0 } }
 
 fn main() { (1 as i32) < 0; }
diff --git a/src/test/pretty/delimited-token-groups.rs b/src/test/pretty/delimited-token-groups.rs
@@ -2,14 +2,14 @@
 
 #![feature(rustc_attrs)]
 
-macro_rules! mac { ($($tt : tt) *) => () }
+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
         {
-            panic! () ;
+            panic!();
 
         }
     }

diff --git a/src/test/pretty/macro.rs b/src/test/pretty/macro.rs
@@ -2,6 +2,6 @@
 
 #![feature(decl_macro)]
 
-pub(crate) macro mac { ($arg : expr) => { $arg + $arg } }
+pub(crate) macro mac { ($arg: expr) => { $arg + $arg } }
 
 fn main() {}
diff --git a/src/test/pretty/macro_rules.rs b/src/test/pretty/macro_rules.rs
@@ -1,19 +1,19 @@
 // pp-exact
 
-macro_rules! brace { () => {} ; }
+macro_rules! brace { () => {}; }
 
-macro_rules! bracket[() => {} ;];
+macro_rules! bracket[() => {};];
 
-macro_rules! paren(() => {} ;);
+macro_rules! paren(() => {};);
 
 macro_rules! matcher_brackets {
-    (paren) => {} ; (bracket) => {} ; (brace) => {} ;
+    (paren) => {}; (bracket) => {}; (brace) => {};
 }
 
 macro_rules! all_fragments {
-    ($b : block, $e : expr, $i : ident, $it : item, $l : lifetime, $lit :
-    literal, $m : meta, $p : pat, $pth : path, $s : stmt, $tt : tt, $ty : ty,
-    $vis : vis) => {} ;
+    ($b: block, $e: expr, $i: ident, $it: item, $l: lifetime, $lit: literal,
+    $m: meta, $p: pat, $pth: path, $s: stmt, $tt: tt, $ty: ty, $vis: vis) =>
+    {};
 }
 
 fn main() {}
diff --git a/src/test/pretty/stmt_expr_attributes.rs b/src/test/pretty/stmt_expr_attributes.rs
@@ -114,7 +114,7 @@ fn _8() {
 }
 
 fn _9() {
-    macro_rules! stmt_mac { () => { let _ = () ; } }
+    macro_rules! stmt_mac { () => { let _ = (); } }
 
     #[rustc_dummy]
     stmt_mac!();

diff --git a/src/test/run-make/rustc-macro-dep-files/foo.rs b/src/test/run-make/rustc-macro-dep-files/foo.rs
@@ -7,6 +7,6 @@ use proc_macro::TokenStream;
 #[proc_macro_derive(A)]
 pub fn derive(input: TokenStream) -> TokenStream {
     let input = input.to_string();
-    assert!(input.contains("struct A ;"));
+    assert!(input.contains("struct A;"));
     "struct B;".parse().unwrap()
 }
diff --git a/src/test/ui/async-await/issues/issue-60674.stdout b/src/test/ui/async-await/issues/issue-60674.stdout
@@ -1,3 +1,3 @@
-async fn f(mut x : u8) {}
-async fn g((mut x, y, mut z) : (u8, u8, u8)) {}
-async fn g(mut x : u8, (a, mut b, c) : (u8, u8, u8), y : u8) {}
+async fn f(mut x: u8) {}
+async fn g((mut x, y, mut z): (u8, u8, u8)) {}
+async fn g(mut x: u8, (a, mut b, c): (u8, u8, u8), y: u8) {}
diff --git a/src/test/ui/hygiene/unpretty-debug.stdout b/src/test/ui/hygiene/unpretty-debug.stdout
@@ -8,7 +8,7 @@
 #![feature /* 0#0 */(no_core)]
 #![no_core /* 0#0 */]
 
-macro_rules! foo /* 0#0 */ { ($x : ident) => { y + $x } }
+macro_rules! foo /* 0#0 */ { ($x: ident) => { y + $x } }
 
 fn bar /* 0#0 */() {
     let x /* 0#0 */ = 1;

diff --git a/src/test/ui/macros/stringify.rs b/src/test/ui/macros/stringify.rs
@@ -636,7 +636,7 @@ fn test_item() {
                 () => {};
             }
         ),
-        "macro_rules! stringify { () => {} ; }", // FIXME
+        "macro_rules! stringify { () => {}; }", // FIXME
     );
     assert_eq!(
         stringify_item!(

diff --git a/src/test/ui/macros/trace-macro.stderr b/src/test/ui/macros/trace-macro.stderr
@@ -5,5 +5,5 @@ LL |     println!("Hello, World!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: expanding `println! { "Hello, World!" }`
-   = note: to `{ $crate :: io :: _print($crate :: format_args_nl! ("Hello, World!")) ; }`
+   = note: to `{ $crate::io::_print($crate::format_args_nl!("Hello, World!")); }`
 
diff --git a/src/test/ui/macros/trace_faulty_macros.stderr b/src/test/ui/macros/trace_faulty_macros.stderr
@@ -19,7 +19,7 @@ LL |     my_faulty_macro!();
    |     ^^^^^^^^^^^^^^^^^^
    |
    = note: expanding `my_faulty_macro! {  }`
-   = note: to `my_faulty_macro! (bcd) ;`
+   = note: to `my_faulty_macro!(bcd);`
    = note: expanding `my_faulty_macro! { bcd }`
 
 error: recursion limit reached while expanding `my_recursive_macro!`
@@ -41,13 +41,13 @@ LL |     my_recursive_macro!();
    |     ^^^^^^^^^^^^^^^^^^^^^
    |
    = note: expanding `my_recursive_macro! {  }`
-   = note: to `my_recursive_macro! () ;`
+   = note: to `my_recursive_macro!();`
    = note: expanding `my_recursive_macro! {  }`
-   = note: to `my_recursive_macro! () ;`
+   = note: to `my_recursive_macro!();`
    = note: expanding `my_recursive_macro! {  }`
-   = note: to `my_recursive_macro! () ;`
+   = note: to `my_recursive_macro!();`
    = note: expanding `my_recursive_macro! {  }`
-   = note: to `my_recursive_macro! () ;`
+   = note: to `my_recursive_macro!();`
 
 error: expected expression, found `A { a: a, b: 0, c: _, .. }`
   --> $DIR/trace_faulty_macros.rs:16:9
@@ -75,8 +75,8 @@ LL |     let a = pat_macro!();
    |             ^^^^^^^^^^^^
    |
    = note: expanding `pat_macro! {  }`
-   = note: to `pat_macro! (A { a : a, b : 0, c : _, .. }) ;`
-   = note: expanding `pat_macro! { A { a : a, b : 0, c : _, .. } }`
+   = note: to `pat_macro!(A { a: a, b: 0, c: _, .. });`
+   = note: expanding `pat_macro! { A { a: a, b: 0, c: _, .. } }`
    = note: to `A { a: a, b: 0, c: _, .. }`
 
 error: aborting due to 4 previous errors

diff --git a/src/test/ui/proc-macro/allowed-attr-stmt-expr.stdout b/src/test/ui/proc-macro/allowed-attr-stmt-expr.stdout
@@ -1,4 +1,4 @@
-PRINT-ATTR INPUT (DISPLAY): struct ItemWithSemi ;
+PRINT-ATTR INPUT (DISPLAY): struct ItemWithSemi;
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
@@ -45,7 +45,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/allowed-attr-stmt-expr.rs:53:27: 53:29 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): #[expect_let] let string = "Hello, world!" ;
+PRINT-ATTR INPUT (DISPLAY): #[expect_let] let string = "Hello, world!";
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Punct {
         ch: '#',
@@ -87,7 +87,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/allowed-attr-stmt-expr.rs:57:33: 57:34 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): #[expect_my_macro_stmt] my_macro! ("{}", string) ;
+PRINT-ATTR INPUT (DISPLAY): #[expect_my_macro_stmt] my_macro!("{}", string);
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Punct {
         ch: '#',
@@ -140,7 +140,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/allowed-attr-stmt-expr.rs:61:28: 61:29 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): second_make_stmt! (#[allow(dead_code)] struct Bar {}) ;
+PRINT-ATTR INPUT (DISPLAY): second_make_stmt!(#[allow(dead_code)] struct Bar {});
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "second_make_stmt",
@@ -288,7 +288,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/allowed-attr-stmt-expr.rs:68:18: 68:20 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): #[rustc_dummy] struct NonBracedStruct ;
+PRINT-ATTR INPUT (DISPLAY): #[rustc_dummy] struct NonBracedStruct;
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Punct {
         ch: '#',

diff --git a/src/test/ui/proc-macro/attr-complex-fn.stdout b/src/test/ui/proc-macro/attr-complex-fn.stdout
@@ -1,4 +1,4 @@
-PRINT-ATTR INPUT (DISPLAY): fn foo < T : MyTrait < MyStruct < { true } >> > () {}
+PRINT-ATTR INPUT (DISPLAY): fn foo < T: MyTrait < MyStruct < { true } >> > () {}
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "fn",
@@ -76,7 +76,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/attr-complex-fn.rs:19:42: 19:44 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): impl < T > MyTrait < T > for MyStruct < { true } > { #! [rustc_dummy] }
+PRINT-ATTR INPUT (DISPLAY): impl < T > MyTrait < T > for MyStruct < { true } > { #![rustc_dummy] }
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "impl",

diff --git a/src/test/ui/proc-macro/attr-stmt-expr.stdout b/src/test/ui/proc-macro/attr-stmt-expr.stdout
@@ -29,7 +29,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/attr-stmt-expr.rs:45:27: 45:29 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): #[expect_let] let string = "Hello, world!" ;
+PRINT-ATTR INPUT (DISPLAY): #[expect_let] let string = "Hello, world!";
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Punct {
         ch: '#',
@@ -71,7 +71,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/attr-stmt-expr.rs:49:33: 49:34 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): #[expect_my_macro_stmt] my_macro! ("{}", string) ;
+PRINT-ATTR INPUT (DISPLAY): #[expect_my_macro_stmt] my_macro!("{}", string);
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Punct {
         ch: '#',
@@ -124,7 +124,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
         span: $DIR/attr-stmt-expr.rs:53:28: 53:29 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): second_make_stmt! (#[allow(dead_code)] struct Bar {}) ;
+PRINT-ATTR INPUT (DISPLAY): second_make_stmt!(#[allow(dead_code)] struct Bar {});
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "second_make_stmt",

diff --git a/src/test/ui/proc-macro/attribute-after-derive.stdout b/src/test/ui/proc-macro/attribute-after-derive.stdout
@@ -1,4 +1,4 @@
-PRINT-ATTR INPUT (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field : u8, }
+PRINT-ATTR INPUT (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field: u8, }
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Punct {
         ch: '#',
@@ -130,7 +130,7 @@ PRINT-DERIVE INPUT (DEBUG): TokenStream [
         span: $DIR/attribute-after-derive.rs:23:24: 26:2 (#0),
     },
 ]
-PRINT-ATTR INPUT (DISPLAY): struct DeriveAttribute { #[cfg(FALSE)] field : u8, }
+PRINT-ATTR INPUT (DISPLAY): struct DeriveAttribute { #[cfg(FALSE)] field: u8, }
 PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",

diff --git a/src/test/ui/proc-macro/attribute-spans-preserved.stdout b/src/test/ui/proc-macro/attribute-spans-preserved.stdout
@@ -1 +1 @@
-fn main() { let y : u32 = "z" ; { let x : u32 = "y" ; } }
+fn main() { let y: u32 = "z"; { let x: u32 = "y"; } }
diff --git a/src/test/ui/proc-macro/auxiliary/attr-stmt-expr-rpass.rs b/src/test/ui/proc-macro/auxiliary/attr-stmt-expr-rpass.rs
@@ -10,14 +10,14 @@ use proc_macro::TokenStream;
 #[proc_macro_attribute]
 pub fn expect_let(attr: TokenStream, item: TokenStream) -> TokenStream {
     assert!(attr.to_string().is_empty());
-    assert_eq!(item.to_string(), "let string = \"Hello, world!\" ;");
+    assert_eq!(item.to_string(), "let string = \"Hello, world!\";");
     item
 }
 
 #[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
 }
 

diff --git a/src/test/ui/proc-macro/auxiliary/attr-stmt-expr.rs b/src/test/ui/proc-macro/auxiliary/attr-stmt-expr.rs
@@ -10,14 +10,14 @@ use proc_macro::TokenStream;
 #[proc_macro_attribute]
 pub fn expect_let(attr: TokenStream, item: TokenStream) -> TokenStream {
     assert!(attr.to_string().is_empty());
-    assert_eq!(item.to_string(), "let string = \"Hello, world!\" ;");
+    assert_eq!(item.to_string(), "let string = \"Hello, world!\";");
     item
 }
 
 #[proc_macro_attribute]
 pub fn expect_my_macro_stmt(attr: TokenStream, item: TokenStream) -> TokenStream {
     assert!(attr.to_string().is_empty());
-    assert_eq!(item.to_string(), "my_macro! (\"{}\", string) ;");
+    assert_eq!(item.to_string(), "my_macro!(\"{}\", string);");
     item
 }
 
@@ -31,7 +31,7 @@ pub fn expect_expr(attr: TokenStream, item: TokenStream) -> TokenStream {
 #[proc_macro_attribute]
 pub fn expect_my_macro_expr(attr: TokenStream, item: TokenStream) -> TokenStream {
     assert!(attr.to_string().is_empty());
-    assert_eq!(item.to_string(), "my_macro! (\"{}\", string)");
+    assert_eq!(item.to_string(), "my_macro!(\"{}\", string)");
     item
 }
 

diff --git a/src/test/ui/proc-macro/auxiliary/derive-a.rs b/src/test/ui/proc-macro/auxiliary/derive-a.rs
@@ -10,6 +10,6 @@ use proc_macro::TokenStream;
 #[proc_macro_derive(A)]
 pub fn derive(input: TokenStream) -> TokenStream {
     let input = input.to_string();
-    assert!(input.contains("struct A ;"));
+    assert!(input.contains("struct A;"));
     "".parse().unwrap()
 }
diff --git a/src/test/ui/proc-macro/auxiliary/derive-atob.rs b/src/test/ui/proc-macro/auxiliary/derive-atob.rs
@@ -10,6 +10,6 @@ use proc_macro::TokenStream;
 #[proc_macro_derive(AToB)]
 pub fn derive(input: TokenStream) -> TokenStream {
     let input = input.to_string();
-    assert_eq!(input, "struct A ;");
+    assert_eq!(input, "struct A;");
     "struct B;".parse().unwrap()
 }
diff --git a/src/test/ui/proc-macro/auxiliary/derive-ctod.rs b/src/test/ui/proc-macro/auxiliary/derive-ctod.rs
@@ -10,6 +10,6 @@ use proc_macro::TokenStream;
 #[proc_macro_derive(CToD)]
 pub fn derive(input: TokenStream) -> TokenStream {
     let input = input.to_string();
-    assert_eq!(input, "struct C ;");
+    assert_eq!(input, "struct C;");
     "struct D;".parse().unwrap()
 }
diff --git a/src/test/ui/proc-macro/auxiliary/derive-same-struct.rs b/src/test/ui/proc-macro/auxiliary/derive-same-struct.rs
@@ -10,12 +10,12 @@ use proc_macro::TokenStream;
 #[proc_macro_derive(AToB)]
 pub fn derive1(input: TokenStream) -> TokenStream {
     println!("input1: {:?}", input.to_string());
-    assert_eq!(input.to_string(), "struct A ;");
+    assert_eq!(input.to_string(), "struct A;");
     "#[derive(BToC)] struct B;".parse().unwrap()
 }
 
 #[proc_macro_derive(BToC)]
 pub fn derive2(input: TokenStream) -> TokenStream {
-    assert_eq!(input.to_string(), "struct B ;");
+    assert_eq!(input.to_string(), "struct B;");
     "struct C;".parse().unwrap()
 }
diff --git a/src/test/ui/proc-macro/auxiliary/derive-union.rs b/src/test/ui/proc-macro/auxiliary/derive-union.rs
@@ -12,7 +12,7 @@ pub fn derive(input: TokenStream) -> TokenStream {
     let input = input.to_string();
     assert!(input.contains("#[repr(C)]"));
     assert!(input.contains("union Test {"));
-    assert!(input.contains("a : u8,"));
+    assert!(input.contains("a: u8,"));
     assert!(input.contains("}"));
     "".parse().unwrap()
 }