Rollup merge of #138063 - compiler-errors:improve-attr-unpretty, r=jdonszelmann

Improve `-Zunpretty=hir` for parsed attrs

0. Rename `print_something` to `should_render` to make it distinct from `print_attribute` in that it doesn't print anything, it's just a way to probe if a type renders anything.
1. Fixes a few bugs in the `PrintAttribute` derive. Namely, the `__printed_anything` variable was entangled with the `should_render` call, leading us to always render field names but never render commas.
2. Remove the outermost `""` from the attr.
3. Debug print `Symbol`s. I know that this is redundant for some parsed attributes, but there's no good way to distinguish symbols that are ident-like and symbols which are cooked string literals. We could perhaps *conditionally* to fall back to a debug printing if the symbol doesn't match an ident? But seems like overkill.

Based on #138060, only review the commits not in that one.

1 files changed, 30 insertions, 22 deletions

diff --git a/compiler/rustc_attr_data_structures/src/lib.rs b/compiler/rustc_attr_data_structures/src/lib.rs
index f4986d1d187..389d8c2413b 100644
--- a/compiler/rustc_attr_data_structures/src/lib.rs
+++ b/compiler/rustc_attr_data_structures/src/lib.rs
@@ -35,13 +35,17 @@ pub trait HashStableContext: rustc_ast::HashStableContext + rustc_abi::HashStabl
 /// like [`Span`]s and empty tuples, are gracefully skipped so they don't clutter the
 /// representation much.
 pub trait PrintAttribute {
-    fn print_something(&self) -> bool;
+    /// Whether or not this will render as something meaningful, or if it's skipped
+    /// (which will force the containing struct to also skip printing a comma
+    /// and the field name).
+    fn should_render(&self) -> bool;
+
     fn print_attribute(&self, p: &mut Printer);
 }
 
 impl<T: PrintAttribute> PrintAttribute for &T {
-    fn print_something(&self) -> bool {
-        T::print_something(self)
+    fn should_render(&self) -> bool {
+        T::should_render(self)
     }
 
     fn print_attribute(&self, p: &mut Printer) {
@@ -49,9 +53,10 @@ impl<T: PrintAttribute> PrintAttribute for &T {
     }
 }
 impl<T: PrintAttribute> PrintAttribute for Option<T> {
-    fn print_something(&self) -> bool {
-        self.as_ref().is_some_and(|x| x.print_something())
+    fn should_render(&self) -> bool {
+        self.as_ref().is_some_and(|x| x.should_render())
     }
+
     fn print_attribute(&self, p: &mut Printer) {
         if let Some(i) = self {
             T::print_attribute(i, p)
@@ -59,9 +64,10 @@ impl<T: PrintAttribute> PrintAttribute for Option<T> {
     }
 }
 impl<T: PrintAttribute> PrintAttribute for ThinVec<T> {
-    fn print_something(&self) -> bool {
-        self.is_empty() || self[0].print_something()
+    fn should_render(&self) -> bool {
+        self.is_empty() || self[0].should_render()
     }
+
     fn print_attribute(&self, p: &mut Printer) {
         let mut last_printed = false;
         p.word("[");
@@ -70,7 +76,7 @@ impl<T: PrintAttribute> PrintAttribute for ThinVec<T> {
                 p.word_space(",");
             }
             i.print_attribute(p);
-            last_printed = i.print_something();
+            last_printed = i.should_render();
         }
         p.word("]");
     }
@@ -78,7 +84,7 @@ impl<T: PrintAttribute> PrintAttribute for ThinVec<T> {
 macro_rules! print_skip {
     ($($t: ty),* $(,)?) => {$(
         impl PrintAttribute for $t {
-            fn print_something(&self) -> bool { false }
+            fn should_render(&self) -> bool { false }
             fn print_attribute(&self, _: &mut Printer) { }
         })*
     };
@@ -87,7 +93,7 @@ macro_rules! print_skip {
 macro_rules! print_disp {
     ($($t: ty),* $(,)?) => {$(
         impl PrintAttribute for $t {
-            fn print_something(&self) -> bool { true }
+            fn should_render(&self) -> bool { true }
             fn print_attribute(&self, p: &mut Printer) {
                 p.word(format!("{}", self));
             }
@@ -97,7 +103,7 @@ macro_rules! print_disp {
 macro_rules! print_debug {
     ($($t: ty),* $(,)?) => {$(
         impl PrintAttribute for $t {
-            fn print_something(&self) -> bool { true }
+            fn should_render(&self) -> bool { true }
             fn print_attribute(&self, p: &mut Printer) {
                 p.word(format!("{:?}", self));
             }
@@ -106,37 +112,39 @@ macro_rules! print_debug {
 }
 
 macro_rules! print_tup {
-    (num_print_something $($ts: ident)*) => { 0 $(+ $ts.print_something() as usize)* };
+    (num_should_render $($ts: ident)*) => { 0 $(+ $ts.should_render() as usize)* };
     () => {};
     ($t: ident $($ts: ident)*) => {
         #[allow(non_snake_case, unused)]
         impl<$t: PrintAttribute, $($ts: PrintAttribute),*> PrintAttribute for ($t, $($ts),*) {
-            fn print_something(&self) -> bool {
+            fn should_render(&self) -> bool {
                 let ($t, $($ts),*) = self;
-                print_tup!(num_print_something $t $($ts)*) != 0
+                print_tup!(num_should_render $t $($ts)*) != 0
             }
 
             fn print_attribute(&self, p: &mut Printer) {
                 let ($t, $($ts),*) = self;
-                let parens = print_tup!(num_print_something $t $($ts)*) > 1;
+                let parens = print_tup!(num_should_render $t $($ts)*) > 1;
                 if parens {
-                    p.word("(");
+                    p.popen();
                 }
 
-                let mut printed_anything = $t.print_something();
+                let mut printed_anything = $t.should_render();
 
                 $t.print_attribute(p);
 
                 $(
-                    if printed_anything && $ts.print_something() {
-                        p.word_space(",");
+                    if $ts.should_render() {
+                        if printed_anything {
+                            p.word_space(",");
+                        }
                         printed_anything = true;
                     }
                     $ts.print_attribute(p);
                 )*
 
                 if parens {
-                    p.word(")");
+                    p.pclose();
                 }
             }
         }
@@ -147,8 +155,8 @@ macro_rules! print_tup {
 
 print_tup!(A B C D E F G H);
 print_skip!(Span, ());
-print_disp!(Symbol, u16, bool, NonZero<u32>);
-print_debug!(UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
+print_disp!(u16, bool, NonZero<u32>);
+print_debug!(Symbol, UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
 
 /// Finds attributes in sequences of attributes by pattern matching.
 ///