Issue-5892: Type alias generic rewrite follows the same rule as trait

rewrite

Author: johnhuichen

src/items.rs

@@ -1766,12 +1766,24 @@ fn rewrite_ty<R: Rewrite>(
         result.push_str(&generics_str);
     }
 
-    if let Some(bounds) = generic_bounds_opt {
-        if !bounds.is_empty() {
+    if let Some(bounds) = generic_bounds_opt
+        && !bounds.is_empty()
+    {
+        if context.config.style_edition() <= StyleEdition::Edition2021 {
             // 2 = `: `
             let shape = Shape::indented(indent, context.config).offset_left(result.len() + 2)?;
             let type_bounds = bounds.rewrite(context, shape).map(|s| format!(": {}", s))?;
             result.push_str(&type_bounds);
+        } else {
+            let shape = Shape::indented(indent, context.config).offset_left(result.len())?;
+            result = rewrite_assign_rhs_with(
+                context,
+                result.clone() + ":",
+                bounds,
+                shape,
+                &RhsAssignKind::Bounds,
+                RhsTactics::ForceNextLineWithoutIndent,
+            )?;
         }
     }
 

tests/source/issue-5892.rs

@@ -0,0 +1,33 @@
+// rustfmt-style_edition: 2024
+
+type AAAAAAAAAAAAA:
+    BBBBBBBBBBBBBBB<
+        CCCCCCCCCCCCCCCCC,
+        DDDDDDDDDDDDDDDDD,
+        EEEEEEEEEEEEEEEEE,
+        FFFFFFFFFFFFFFFFF,
+        GGGGGGGGGGGGGGGGG,
+        HHHHHHHHHHHHHHHHH,
+        IIIIIIIIIIIIIIIII,
+    >;
+
+type AAAAAAAAAAAAA:
+    BBBBBBBBBBBBBBB<
+        CCCCCCCCCCCCCCCCC,
+        DDDDDDDDDDDDDDDDD,
+        EEEEEEEEEEEEEEEEE,
+        FFFFFFFFFFFFFFFFF,
+        GGGGGGGGGGGGGGGGG,
+        HHHHHHHHHHHHHHHHH,
+        IIIIIIIIIIIIIIIII,
+    > + Eq
+    + PartialEq;
+
+// previous error: maximum length exceeded
+type SomeType:
+    BBBBBBBBBBBBBBB<CCCCCCCCCCCCCCCCC, DDDDDDDDDDDDDDDDD, EEEEEEEEEEEEEEEEE, FFFFFFFFFFFFFFFFF>
+    + AAAAAAAAAAAAA;
+
+// previous error: maximum length exceeded
+type SomeType:
+    BBBBBBBBBBBBBBB<CCCCCCCCCCCCCCCCC, DDDDDDDDDDDDDDDDD, EEEEEEEEEEEEEEEEE, FFFFFFFFFFFFFFFFF>;

tests/target/issue-5892.rs

@@ -0,0 +1,33 @@
+// rustfmt-style_edition: 2024
+
+type AAAAAAAAAAAAA:
+    BBBBBBBBBBBBBBB<
+        CCCCCCCCCCCCCCCCC,
+        DDDDDDDDDDDDDDDDD,
+        EEEEEEEEEEEEEEEEE,
+        FFFFFFFFFFFFFFFFF,
+        GGGGGGGGGGGGGGGGG,
+        HHHHHHHHHHHHHHHHH,
+        IIIIIIIIIIIIIIIII,
+    >;
+
+type AAAAAAAAAAAAA:
+    BBBBBBBBBBBBBBB<
+        CCCCCCCCCCCCCCCCC,
+        DDDDDDDDDDDDDDDDD,
+        EEEEEEEEEEEEEEEEE,
+        FFFFFFFFFFFFFFFFF,
+        GGGGGGGGGGGGGGGGG,
+        HHHHHHHHHHHHHHHHH,
+        IIIIIIIIIIIIIIIII,
+    > + Eq
+    + PartialEq;
+
+// previous error: maximum length exceeded
+type SomeType:
+    BBBBBBBBBBBBBBB<CCCCCCCCCCCCCCCCC, DDDDDDDDDDDDDDDDD, EEEEEEEEEEEEEEEEE, FFFFFFFFFFFFFFFFF>
+    + AAAAAAAAAAAAA;
+
+// previous error: maximum length exceeded
+type SomeType:
+    BBBBBBBBBBBBBBB<CCCCCCCCCCCCCCCCC, DDDDDDDDDDDDDDDDD, EEEEEEEEEEEEEEEEE, FFFFFFFFFFFFFFFFF>;