Extract ast TraitImplHeader

Author: camsteffen

src/items.rs

@@ -958,20 +958,19 @@ fn format_impl_ref_and_type(
     offset: Indent,
 ) -> Option<String> {
     let ast::Impl {
-        safety,
-        polarity,
-        defaultness,
-        constness,
-        ref generics,
-        of_trait: ref trait_ref,
-        ref self_ty,
-        ..
-    } = *iimpl;
+        generics,
+        of_trait,
+        self_ty,
+        items: _,
+    } = iimpl;
     let mut result = String::with_capacity(128);
 
     result.push_str(&format_visibility(context, &item.vis));
-    result.push_str(format_defaultness(defaultness));
-    result.push_str(format_safety(safety));
+
+    if let Some(of_trait) = of_trait.as_deref() {
+        result.push_str(format_defaultness(of_trait.defaultness));
+        result.push_str(format_safety(of_trait.safety));
+    }
 
     let shape = if context.config.style_edition() >= StyleEdition::Edition2024 {
         Shape::indented(offset + last_line_width(&result), context.config)
@@ -984,28 +983,24 @@ fn format_impl_ref_and_type(
     };
     let generics_str = rewrite_generics(context, "impl", generics, shape).ok()?;
     result.push_str(&generics_str);
-    result.push_str(format_constness_right(constness));
 
-    let polarity_str = match polarity {
-        ast::ImplPolarity::Negative(_) => "!",
-        ast::ImplPolarity::Positive => "",
-    };
-
-    let polarity_overhead;
     let trait_ref_overhead;
-    if let Some(ref trait_ref) = *trait_ref {
+    if let Some(of_trait) = of_trait.as_deref() {
+        result.push_str(format_constness_right(of_trait.constness));
+        let polarity_str = match of_trait.polarity {
+            ast::ImplPolarity::Negative(_) => "!",
+            ast::ImplPolarity::Positive => "",
+        };
         let result_len = last_line_width(&result);
         result.push_str(&rewrite_trait_ref(
             context,
-            trait_ref,
+            &of_trait.trait_ref,
             offset,
             polarity_str,
             result_len,
         )?);
-        polarity_overhead = 0; // already written
         trait_ref_overhead = " for".len();
     } else {
-        polarity_overhead = polarity_str.len();
         trait_ref_overhead = 0;
     }
 
@@ -1020,17 +1015,15 @@ fn format_impl_ref_and_type(
     } else {
         0
     };
-    let used_space =
-        last_line_width(&result) + polarity_overhead + trait_ref_overhead + curly_brace_overhead;
+    let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
     // 1 = space before the type.
     let budget = context.budget(used_space + 1);
     if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
         if !self_ty_str.contains('\n') {
-            if trait_ref.is_some() {
+            if of_trait.is_some() {
                 result.push_str(" for ");
             } else {
                 result.push(' ');
-                result.push_str(polarity_str);
             }
             result.push_str(&self_ty_str);
             return Some(result);
@@ -1042,12 +1035,10 @@ fn format_impl_ref_and_type(
     // Add indentation of one additional tab.
     let new_line_offset = offset.block_indent(context.config);
     result.push_str(&new_line_offset.to_string(context.config));
-    if trait_ref.is_some() {
+    if of_trait.is_some() {
         result.push_str("for ");
-    } else {
-        result.push_str(polarity_str);
     }
-    let budget = context.budget(last_line_width(&result) + polarity_overhead);
+    let budget = context.budget(last_line_width(&result));
     let type_offset = match context.config.indent_style() {
         IndentStyle::Visual => new_line_offset + trait_ref_overhead,
         IndentStyle::Block => new_line_offset,

tests/source/negative-impl.rs

@@ -1,7 +1,3 @@
 impl ! Display for JoinHandle { }
 
-impl ! Box < JoinHandle > { }
-
 impl ! std :: fmt :: Display for JoinHandle < T : std :: future :: Future + std :: marker :: Send + std :: marker :: Sync > { }
-
-impl ! JoinHandle < T : std :: future :: Future < Output > + std :: marker :: Send + std :: marker :: Sync + 'static > + 'static { }

tests/target/negative-impl.rs

@@ -1,14 +1,6 @@
 impl !Display for JoinHandle {}
 
-impl !Box<JoinHandle> {}
-
 impl !std::fmt::Display
     for JoinHandle<T: std::future::Future + std::marker::Send + std::marker::Sync>
 {
 }
-
-impl
-    !JoinHandle<T: std::future::Future<Output> + std::marker::Send + std::marker::Sync + 'static>
-        + 'static
-{
-}