diff --git a/tests/source/trait.rs b/tests/source/trait.rs
index 823b1e44a1e..e8de36db35e 100644
--- a/tests/source/trait.rs
+++ b/tests/source/trait.rs
@@ -72,6 +72,11 @@ trait Foo {
     type IteRev = <MergingUntypedTimeSeries<SliceSeries<SliceWindow>> as UntypedTimeSeries>::IterRev;
 }
 
+// #2331
+trait MyTrait<AAAAAAAAAAAAAAAAAAAA, BBBBBBBBBBBBBBBBBBBB, CCCCCCCCCCCCCCCCCCCC, DDDDDDDDDDDDDDDDDDDD> {
+    fn foo() {}
+}
+
 // Trait aliases
 trait FooBar =
     Foo 
diff --git a/tests/target/big-impl-rfc.rs b/tests/target/big-impl-rfc.rs
index de2af2d1807..bc16f12c9d7 100644
--- a/tests/target/big-impl-rfc.rs
+++ b/tests/target/big-impl-rfc.rs
@@ -29,11 +29,13 @@ where
 
 // #1369
 impl<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName> Foo
-    for Bar {
+    for Bar
+{
     fn foo() {}
 }
 impl Foo<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName>
-    for Bar {
+    for Bar
+{
     fn foo() {}
 }
 impl<
@@ -41,7 +43,8 @@ impl<
     ExcessivelyLongGenericName,
     AnotherExcessivelyLongGenericName,
 > Foo<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName>
-    for Bar {
+    for Bar
+{
     fn foo() {}
 }
 impl<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName> Foo
diff --git a/tests/target/big-impl.rs b/tests/target/big-impl.rs
index 056ded71daa..6f122e7e0b6 100644
--- a/tests/target/big-impl.rs
+++ b/tests/target/big-impl.rs
@@ -27,11 +27,13 @@ where
 
 // #1369
 impl<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName> Foo
-    for Bar {
+    for Bar
+{
     fn foo() {}
 }
 impl Foo<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName>
-    for Bar {
+    for Bar
+{
     fn foo() {}
 }
 impl<
@@ -39,7 +41,8 @@ impl<
     ExcessivelyLongGenericName,
     AnotherExcessivelyLongGenericName,
 > Foo<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName>
-    for Bar {
+    for Bar
+{
     fn foo() {}
 }
 impl<ExcessivelyLongGenericName, ExcessivelyLongGenericName, AnotherExcessivelyLongGenericName> Foo
diff --git a/tests/target/impls.rs b/tests/target/impls.rs
index a743d7f3067..91172b39fe5 100644
--- a/tests/target/impls.rs
+++ b/tests/target/impls.rs
@@ -141,11 +141,13 @@ mod m {
 }
 
 impl<BorrowType, K, V, NodeType, HandleType>
-    Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
+    Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType>
+{
 }
 
 impl<BorrowType, K, V, NodeType, HandleType> PartialEq
-    for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType> {
+    for Handle<NodeRef<BorrowType, K, V, NodeType>, HandleType>
+{
 }
 
 mod x {
@@ -160,7 +162,8 @@ mod x {
 }
 
 impl<ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNodeFoo>
-    Issue1249<ConcreteThreadSafeLayoutNode> {
+    Issue1249<ConcreteThreadSafeLayoutNode>
+{
     // Creates a new flow constructor.
     fn foo() {}
 }
diff --git a/tests/target/trait.rs b/tests/target/trait.rs
index a570cb4d540..e4d78f72229 100644
--- a/tests/target/trait.rs
+++ b/tests/target/trait.rs
@@ -100,6 +100,17 @@ trait Foo {
         <MergingUntypedTimeSeries<SliceSeries<SliceWindow>> as UntypedTimeSeries>::IterRev;
 }
 
+// #2331
+trait MyTrait<
+    AAAAAAAAAAAAAAAAAAAA,
+BBBBBBBBBBBBBBBBBBBB,
+CCCCCCCCCCCCCCCCCCCC,
+DDDDDDDDDDDDDDDDDDDD,
+> {
+    fn foo() {}
+}
+
+
 // Trait aliases
 trait FooBar = Foo + Bar;
 trait FooBar<A, B, C> = Foo + Bar;