diff --git a/tests/init-global/neg/global-cycle1.check b/tests/init-global/neg/global-cycle1.check
index faed741761a7..c68b8b51a419 100644
--- a/tests/init-global/neg/global-cycle1.check
+++ b/tests/init-global/neg/global-cycle1.check
@@ -2,19 +2,19 @@
 1 |object A {             // error
   |       ^
   |       Cyclic initialization: object A -> object B -> object A. Calling trace:
-  |       -> object A {             // error	[ global-cycle1.scala:1 ]
-  |          ^
-  |       -> val a: Int = B.b	[ global-cycle1.scala:2 ]
-  |                       ^
-  |       -> object B {	[ global-cycle1.scala:5 ]
-  |          ^
-  |       -> val b: Int = A.a     // error	[ global-cycle1.scala:6 ]
-  |                       ^
+  |       ├── object A {             // error	[ global-cycle1.scala:1 ]
+  |       │   ^
+  |       ├── val a: Int = B.b	[ global-cycle1.scala:2 ]
+  |       │                ^
+  |       ├── object B {	[ global-cycle1.scala:5 ]
+  |       │   ^
+  |       └── val b: Int = A.a     // error	[ global-cycle1.scala:6 ]
+  |                        ^
 -- Error: tests/init-global/neg/global-cycle1.scala:6:17 ---------------------------------------------------------------
 6 |  val b: Int = A.a     // error
   |               ^^^
-  |               Access uninitialized field value a. Call trace: 
-  |               -> object B {	[ global-cycle1.scala:5 ]
-  |                  ^
-  |               -> val b: Int = A.a     // error	[ global-cycle1.scala:6 ]
-  |                               ^^^
+  |               Access uninitialized field value a. Calling trace:
+  |               ├── object B {	[ global-cycle1.scala:5 ]
+  |               │   ^
+  |               └── val b: Int = A.a     // error	[ global-cycle1.scala:6 ]
+  |                                ^^^
diff --git a/tests/init-global/neg/line-spacing.check b/tests/init-global/neg/line-spacing.check
index ab44d7d1dc65..6fa8801bb07b 100644
--- a/tests/init-global/neg/line-spacing.check
+++ b/tests/init-global/neg/line-spacing.check
@@ -2,12 +2,12 @@
 3 |    B
 4 |      .s.length // error
   |    ^
-  |    Access uninitialized field value s. Call trace: 
-  |    -> object B {	[ line-spacing.scala:7 ]
-  |       ^
-  |    -> val s: String = s"${A.a}a"	[ line-spacing.scala:8 ]
-  |                           ^^^
-  |    -> def a: Int =	[ line-spacing.scala:2 ]
-  |       ^
-  |    -> .s.length // error	[ line-spacing.scala:4 ]
-  |       ^
+  |    Access uninitialized field value s. Calling trace:
+  |    ├── object B {	[ line-spacing.scala:7 ]
+  |    │   ^
+  |    ├── val s: String = s"${A.a}a"	[ line-spacing.scala:8 ]
+  |    │                       ^^^
+  |    ├── def a: Int =	[ line-spacing.scala:2 ]
+  |    │   ^
+  |    └── .s.length // error	[ line-spacing.scala:4 ]
+  |        ^
diff --git a/tests/init-global/neg/patmat-unapplySeq.check b/tests/init-global/neg/patmat-unapplySeq.check
index 74093b029614..8f7a1f64631b 100644
--- a/tests/init-global/neg/patmat-unapplySeq.check
+++ b/tests/init-global/neg/patmat-unapplySeq.check
@@ -2,10 +2,10 @@
 8 |  def apply(i: Int): Box = array(i)             // error
   |                           ^^^^^^^^
   |Reading mutable state of object A during initialization of object B.
-  |Reading mutable state of other static objects is forbidden as it breaks initialization-time irrelevance. Calling trace: 
-  |-> object B:	[ patmat-unapplySeq.scala:15 ]
-  |   ^
-  |-> case A(b) =>	[ patmat-unapplySeq.scala:17 ]
-  |        ^^^^
-  |-> def apply(i: Int): Box = array(i)             // error	[ patmat-unapplySeq.scala:8 ]
-  |                            ^^^^^^^^
+  |Reading mutable state of other static objects is forbidden as it breaks initialization-time irrelevance. Calling trace:
+  |├── object B:	[ patmat-unapplySeq.scala:15 ]
+  |│   ^
+  |├── case A(b) =>	[ patmat-unapplySeq.scala:17 ]
+  |│        ^^^^
+  |└── def apply(i: Int): Box = array(i)             // error	[ patmat-unapplySeq.scala:8 ]
+  |                             ^^^^^^^^
diff --git a/tests/init/neg/closureLeak.check b/tests/init/neg/closureLeak.check
index a90acaa8ed00..2631072eaa11 100644
--- a/tests/init/neg/closureLeak.check
+++ b/tests/init/neg/closureLeak.check
@@ -2,13 +2,13 @@
 11 |    l.foreach(a => a.addX(this)) // error
    |              ^^^^^^^^^^^^^^^^^
    |Could not verify that the method argument is transitively initialized (Hot). It was found to be a function where "this" is (the original object of type (class Outer) where initialization checking started). Only transitively initialized arguments may be passed to methods (except constructors). Calling trace:
-   |-> class Outer {	[ closureLeak.scala:1 ]
-   |   ^
-   |-> l.foreach(a => a.addX(this)) // error	[ closureLeak.scala:11 ]
-   |             ^^^^^^^^^^^^^^^^^
+   |├── class Outer {	[ closureLeak.scala:1 ]
+   |│   ^
+   |└── l.foreach(a => a.addX(this)) // error	[ closureLeak.scala:11 ]
+   |              ^^^^^^^^^^^^^^^^^
    |
    |Promoting the value to transitively initialized (Hot) failed due to the following problem:
    |Could not verify that the method argument is transitively initialized (Hot). It was found to be the original object of type (class Outer) where initialization checking started. Only transitively initialized arguments may be passed to methods (except constructors).
    |Non initialized field(s): value p. Promotion trace:
-   |-> l.foreach(a => a.addX(this)) // error	[ closureLeak.scala:11 ]
-   |                         ^^^^
+   |└── l.foreach(a => a.addX(this)) // error	[ closureLeak.scala:11 ]
+   |                          ^^^^
diff --git a/tests/init/neg/cycle-structure.check b/tests/init/neg/cycle-structure.check
index dfe7c9b85e2f..b07316cfb2a8 100644
--- a/tests/init/neg/cycle-structure.check
+++ b/tests/init/neg/cycle-structure.check
@@ -2,29 +2,29 @@
 3 |    val x = B(this)   // error
   |            ^^^^^^^
   |            Problematic object instantiation: arg 1 is not transitively initialized (Hot). Calling trace:
-  |            -> case class A(b: B) {	[ cycle-structure.scala:1 ]
-  |               ^
-  |            -> val x = B(this)   // error	[ cycle-structure.scala:3 ]
-  |                       ^^^^^^^
+  |            ├── case class A(b: B) {	[ cycle-structure.scala:1 ]
+  |            │   ^
+  |            └── val x = B(this)   // error	[ cycle-structure.scala:3 ]
+  |                        ^^^^^^^
   |
   |            It leads to the following error during object initialization:
   |            Access field value x on an uninitialized (Cold) object. Calling trace:
-  |            -> case class B(a: A) {	[ cycle-structure.scala:7 ]
-  |               ^
-  |            -> val x1 = a.x	[ cycle-structure.scala:8 ]
-  |                        ^^^
+  |            ├── case class B(a: A) {	[ cycle-structure.scala:7 ]
+  |            │   ^
+  |            └── val x1 = a.x	[ cycle-structure.scala:8 ]
+  |                         ^^^
 -- Error: tests/init/neg/cycle-structure.scala:9:13 --------------------------------------------------------------------
 9 |    val x = A(this)   // error
   |            ^^^^^^^
   |            Problematic object instantiation: arg 1 is not transitively initialized (Hot). Calling trace:
-  |            -> case class B(a: A) {	[ cycle-structure.scala:7 ]
-  |               ^
-  |            -> val x = A(this)   // error	[ cycle-structure.scala:9 ]
-  |                       ^^^^^^^
+  |            ├── case class B(a: A) {	[ cycle-structure.scala:7 ]
+  |            │   ^
+  |            └── val x = A(this)   // error	[ cycle-structure.scala:9 ]
+  |                        ^^^^^^^
   |
   |            It leads to the following error during object initialization:
   |            Access field value x on an uninitialized (Cold) object. Calling trace:
-  |            -> case class A(b: B) {	[ cycle-structure.scala:1 ]
-  |               ^
-  |            -> val x1 = b.x	[ cycle-structure.scala:2 ]
-  |                        ^^^
+  |            ├── case class A(b: B) {	[ cycle-structure.scala:1 ]
+  |            │   ^
+  |            └── val x1 = b.x	[ cycle-structure.scala:2 ]
+  |                         ^^^
diff --git a/tests/init/neg/default-this.check b/tests/init/neg/default-this.check
index f64f36304e9b..88c5d3dcbba0 100644
--- a/tests/init/neg/default-this.check
+++ b/tests/init/neg/default-this.check
@@ -3,11 +3,11 @@
   |        ^^^^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be the original object of type (class B) where initialization checking started. Only transitively initialized arguments may be passed to methods (except constructors).
   |Non initialized field(s): value result. Calling trace:
-  |-> class B extends A {	[ default-this.scala:6 ]
-  |   ^
-  |-> val result = updateThenCompare(5)	[ default-this.scala:11 ]
-  |                ^^^^^^^^^^^^^^^^^^^^
-  |-> def updateThenCompare(c: Int): Boolean = {	[ default-this.scala:7 ]
-  |   ^
-  |-> compare() // error	[ default-this.scala:9 ]
-  |   ^^^^^^^
+  |├── class B extends A {	[ default-this.scala:6 ]
+  |│   ^
+  |├── val result = updateThenCompare(5)	[ default-this.scala:11 ]
+  |│                ^^^^^^^^^^^^^^^^^^^^
+  |├── def updateThenCompare(c: Int): Boolean = {	[ default-this.scala:7 ]
+  |│   ^
+  |└── compare() // error	[ default-this.scala:9 ]
+  |    ^^^^^^^
diff --git a/tests/init/neg/i15363.check b/tests/init/neg/i15363.check
index 9912aa186a5b..d78fc1dcf41b 100644
--- a/tests/init/neg/i15363.check
+++ b/tests/init/neg/i15363.check
@@ -2,14 +2,14 @@
 3 |  val b = new B(this) // error
   |          ^^^^^^^^^^^
   |          Problematic object instantiation: arg 1 is not transitively initialized (Hot). Calling trace:
-  |          -> class A:	[ i15363.scala:1 ]
-  |             ^
-  |          -> val b = new B(this) // error	[ i15363.scala:3 ]
-  |                     ^^^^^^^^^^^
+  |          ├── class A:	[ i15363.scala:1 ]
+  |          │   ^
+  |          └── val b = new B(this) // error	[ i15363.scala:3 ]
+  |                      ^^^^^^^^^^^
   |
   |          It leads to the following error during object initialization:
   |          Access field value m on an uninitialized (Cold) object. Calling trace:
-  |          -> class B(a: A):	[ i15363.scala:7 ]
-  |             ^
-  |          -> val x = a.m	[ i15363.scala:8 ]
-  |                     ^^^
+  |          ├── class B(a: A):	[ i15363.scala:7 ]
+  |          │   ^
+  |          └── val x = a.m	[ i15363.scala:8 ]
+  |                      ^^^
diff --git a/tests/init/neg/i15459.check b/tests/init/neg/i15459.check
index a8c9972276db..5a8b79c2d82d 100644
--- a/tests/init/neg/i15459.check
+++ b/tests/init/neg/i15459.check
@@ -3,9 +3,9 @@
   |          ^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be the original object of type (class Sub) where initialization checking started. Only transitively initialized arguments may be passed to methods (except constructors).
   |Non initialized field(s): value b. Calling trace:
-  |-> class Sub extends Sup:	[ i15459.scala:5 ]
-  |   ^
-  |-> class Sup:	[ i15459.scala:1 ]
-  |   ^
-  |-> println(this)  // error	[ i15459.scala:3 ]
-  |           ^^^^
+  |├── class Sub extends Sup:	[ i15459.scala:5 ]
+  |│   ^
+  |├── class Sup:	[ i15459.scala:1 ]
+  |│   ^
+  |└── println(this)  // error	[ i15459.scala:3 ]
+  |            ^^^^
diff --git a/tests/init/neg/inherit-non-hot.check b/tests/init/neg/inherit-non-hot.check
index 068ba9662fd1..5e3adbe93fd9 100644
--- a/tests/init/neg/inherit-non-hot.check
+++ b/tests/init/neg/inherit-non-hot.check
@@ -2,16 +2,16 @@
 6 |            if b == null then b = new B(this) // error
   |                              ^^^^^^^^^^^^^^^
   |The RHS of reassignment must be transitively initialized (Hot). It was found to be a non-transitively initialized (Warm) object of type (class B) { outer = a transitively initialized (Hot) object, args = (an uninitialized (Cold) object) }.  Calling trace:
-  |-> class C extends A {	[ inherit-non-hot.scala:15 ]
-  |   ^
-  |-> val bAgain = toB.getBAgain	[ inherit-non-hot.scala:16 ]
-  |                ^^^
-  |-> def toB: B =	[ inherit-non-hot.scala:5 ]
-  |   ^
-  |-> if b == null then b = new B(this) // error	[ inherit-non-hot.scala:6 ]
-  |                     ^^^^^^^^^^^^^^^
+  |├── class C extends A {	[ inherit-non-hot.scala:15 ]
+  |│   ^
+  |├── val bAgain = toB.getBAgain	[ inherit-non-hot.scala:16 ]
+  |│                ^^^
+  |├── def toB: B =	[ inherit-non-hot.scala:5 ]
+  |│   ^
+  |└── if b == null then b = new B(this) // error	[ inherit-non-hot.scala:6 ]
+  |                      ^^^^^^^^^^^^^^^
   |
   |Promoting the value to transitively initialized (Hot) failed due to the following problem:
   |Could not verify that the field value a is transitively initialized (Hot). It was found to be an uninitialized (Cold) object. Promotion trace:
-  |-> class B(a: A) {	[ inherit-non-hot.scala:10 ]
-  |           ^^^^
+  |└── class B(a: A) {	[ inherit-non-hot.scala:10 ]
+  |            ^^^^
diff --git a/tests/init/neg/inlined-method.check b/tests/init/neg/inlined-method.check
index f3061bcb63ed..9f084c05cc1b 100644
--- a/tests/init/neg/inlined-method.check
+++ b/tests/init/neg/inlined-method.check
@@ -3,9 +3,9 @@
   |                                             ^^^^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be the original object of type (class InlineError) where initialization checking started. Only transitively initialized arguments may be passed to methods (except constructors).
   |Non initialized field(s): value v. Calling trace:
-  |-> class InlineError {	[ inlined-method.scala:1 ]
-  |   ^
-  |-> Assertion.failAssert(this)	[ inlined-method.scala:2 ]
-  |   ^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |-> scala.runtime.Scala3RunTime.assertFailed(message) // error	[ inlined-method.scala:8 ]
-  |                                            ^^^^^^^
+  |├── class InlineError {	[ inlined-method.scala:1 ]
+  |│   ^
+  |├── Assertion.failAssert(this)	[ inlined-method.scala:2 ]
+  |│   ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |└── scala.runtime.Scala3RunTime.assertFailed(message) // error	[ inlined-method.scala:8 ]
+  |                                             ^^^^^^^
diff --git a/tests/init/neg/inner-first.check b/tests/init/neg/inner-first.check
index fe90423c828f..6f24780ecb5d 100644
--- a/tests/init/neg/inner-first.check
+++ b/tests/init/neg/inner-first.check
@@ -3,7 +3,7 @@
   |            ^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be the original object of type (class B) where initialization checking started. Only transitively initialized arguments may be passed to methods (except constructors).
   |Non initialized field(s): value n. Calling trace:
-  |-> class B:	[ inner-first.scala:2 ]
-  |   ^
-  |-> println(this)           // error	[ inner-first.scala:3 ]
-  |           ^^^^
+  |├── class B:	[ inner-first.scala:2 ]
+  |│   ^
+  |└── println(this)           // error	[ inner-first.scala:3 ]
+  |            ^^^^
diff --git a/tests/init/neg/leak-warm.check b/tests/init/neg/leak-warm.check
index c2fc561a3668..d5ea8a94a272 100644
--- a/tests/init/neg/leak-warm.check
+++ b/tests/init/neg/leak-warm.check
@@ -2,7 +2,7 @@
 19 |    val l2 = l.map(_.m()) // error
    |             ^^^^^^^^^^^^
    |             Call method method map on an uninitialized (Cold) object. Calling trace:
-   |             -> object leakWarm {	[ leak-warm.scala:1 ]
-   |                ^
-   |             -> val l2 = l.map(_.m()) // error	[ leak-warm.scala:19 ]
-   |                         ^^^^^^^^^^^^
+   |             ├── object leakWarm {	[ leak-warm.scala:1 ]
+   |             │   ^
+   |             └── val l2 = l.map(_.m()) // error	[ leak-warm.scala:19 ]
+   |                          ^^^^^^^^^^^^
diff --git a/tests/init/neg/promotion-loop.check b/tests/init/neg/promotion-loop.check
index bc05640d10d2..e4343d7ec412 100644
--- a/tests/init/neg/promotion-loop.check
+++ b/tests/init/neg/promotion-loop.check
@@ -2,13 +2,13 @@
 16 |  println(b)      // error
    |          ^
    |Could not verify that the method argument is transitively initialized (Hot). It was found to be a non-transitively initialized (Warm) object of type (class B) { outer = the original object of type (class Test) where initialization checking started }. Only transitively initialized arguments may be passed to methods (except constructors). Calling trace:
-   |-> class Test { test =>	[ promotion-loop.scala:1 ]
-   |   ^
-   |-> println(b)      // error	[ promotion-loop.scala:16 ]
-   |           ^
+   |├── class Test { test =>	[ promotion-loop.scala:1 ]
+   |│   ^
+   |└── println(b)      // error	[ promotion-loop.scala:16 ]
+   |            ^
    |
    |Promoting the value to transitively initialized (Hot) failed due to the following problem:
    |Could not verify that the field value outer is transitively initialized (Hot). It was found to be the original object of type (class Test) where initialization checking started.
    |Non initialized field(s): value n. Promotion trace:
-   |-> val outer = test	[ promotion-loop.scala:12 ]
-   |   ^^^^^^^^^^^^^^^^
+   |└── val outer = test	[ promotion-loop.scala:12 ]
+   |    ^^^^^^^^^^^^^^^^
diff --git a/tests/init/neg/promotion-segment3.check b/tests/init/neg/promotion-segment3.check
index a7320b5c3ed3..fc152664fb08 100644
--- a/tests/init/neg/promotion-segment3.check
+++ b/tests/init/neg/promotion-segment3.check
@@ -2,10 +2,10 @@
 9 |  bar(new B)  // error
   |      ^^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be a non-transitively initialized (Warm) object of type (class B) { outer = the original object of type (class A) where initialization checking started }. Only transitively initialized arguments may be passed to methods (except constructors). Calling trace:
-  |-> class A:	[ promotion-segment3.scala:2 ]
-  |   ^
-  |-> bar(new B)  // error	[ promotion-segment3.scala:9 ]
-  |       ^^^^^
+  |├── class A:	[ promotion-segment3.scala:2 ]
+  |│   ^
+  |└── bar(new B)  // error	[ promotion-segment3.scala:9 ]
+  |        ^^^^^
   |
   |Promoting the value to transitively initialized (Hot) failed due to the following problem:
   |Promotion cancelled as the value contains inner class C.
diff --git a/tests/init/neg/secondary-ctor4.check b/tests/init/neg/secondary-ctor4.check
index e867ba65ded5..2c89cfe9f289 100644
--- a/tests/init/neg/secondary-ctor4.check
+++ b/tests/init/neg/secondary-ctor4.check
@@ -2,43 +2,43 @@
 54 |      val c = new C(b, 5)   // error
    |              ^^^^^^^^^^^
    |              Problematic object instantiation: arg 1 is not transitively initialized (Hot). Calling trace:
-   |              -> class D {	[ secondary-ctor4.scala:52 ]
-   |                 ^
-   |              -> val c = new C(b, 5)   // error	[ secondary-ctor4.scala:54 ]
-   |                         ^^^^^^^^^^^
+   |              ├── class D {	[ secondary-ctor4.scala:52 ]
+   |              │   ^
+   |              └── val c = new C(b, 5)   // error	[ secondary-ctor4.scala:54 ]
+   |                          ^^^^^^^^^^^
    |
    |              It leads to the following error during object initialization:
    |              Access field value n on an uninitialized (Cold) object. Calling trace:
-   |              -> def this(b: B, x: Int) = this(b)	[ secondary-ctor4.scala:49 ]
-   |                                          ^^^^^^^
-   |              -> class C(b: B) extends A(b) with T {	[ secondary-ctor4.scala:48 ]
-   |                 ^
-   |              -> def this(b: B) = {	[ secondary-ctor4.scala:17 ]
-   |                 ^
-   |              -> Inner().foo()	[ secondary-ctor4.scala:26 ]
-   |                 ^^^^^^^
-   |              -> class Inner() {	[ secondary-ctor4.scala:21 ]
-   |                 ^
-   |              -> println(b.n)	[ secondary-ctor4.scala:23 ]
-   |                         ^^^
+   |              ├── def this(b: B, x: Int) = this(b)	[ secondary-ctor4.scala:49 ]
+   |              │                            ^^^^^^^
+   |              ├── class C(b: B) extends A(b) with T {	[ secondary-ctor4.scala:48 ]
+   |              │   ^
+   |              ├── def this(b: B) = {	[ secondary-ctor4.scala:17 ]
+   |              │   ^
+   |              ├── Inner().foo()	[ secondary-ctor4.scala:26 ]
+   |              │   ^^^^^^^
+   |              ├── class Inner() {	[ secondary-ctor4.scala:21 ]
+   |              │   ^
+   |              └── println(b.n)	[ secondary-ctor4.scala:23 ]
+   |                          ^^^
 -- Error: tests/init/neg/secondary-ctor4.scala:42:4 --------------------------------------------------------------------
 42 |    new A(new B(new D))  // error
    |    ^^^^^^^^^^^^^^^^^^^
    |Problematic object instantiation: the outer M.this and arg 1 are not transitively initialized (Hot). Calling trace:
-   |-> class N(d: D) extends M(d) {	[ secondary-ctor4.scala:59 ]
-   |   ^
-   |-> def this(d: D) = {	[ secondary-ctor4.scala:7 ]
-   |   ^
-   |-> new A(new B(new D))  // error	[ secondary-ctor4.scala:42 ]
-   |   ^^^^^^^^^^^^^^^^^^^
+   |├── class N(d: D) extends M(d) {	[ secondary-ctor4.scala:59 ]
+   |│   ^
+   |├── def this(d: D) = {	[ secondary-ctor4.scala:7 ]
+   |│   ^
+   |└── new A(new B(new D))  // error	[ secondary-ctor4.scala:42 ]
+   |    ^^^^^^^^^^^^^^^^^^^
    |
    |It leads to the following error during object initialization:
    |Access field value n on an uninitialized (Cold) object. Calling trace:
-   |-> def this(b: B) = {	[ secondary-ctor4.scala:17 ]
-   |   ^
-   |-> Inner().foo()	[ secondary-ctor4.scala:26 ]
-   |   ^^^^^^^
-   |-> class Inner() {	[ secondary-ctor4.scala:21 ]
-   |   ^
-   |-> println(b.n)	[ secondary-ctor4.scala:23 ]
-   |           ^^^
+   |├── def this(b: B) = {	[ secondary-ctor4.scala:17 ]
+   |│   ^
+   |├── Inner().foo()	[ secondary-ctor4.scala:26 ]
+   |│   ^^^^^^^
+   |├── class Inner() {	[ secondary-ctor4.scala:21 ]
+   |│   ^
+   |└── println(b.n)	[ secondary-ctor4.scala:23 ]
+   |            ^^^
diff --git a/tests/init/neg/super-resolution.check b/tests/init/neg/super-resolution.check
index d5fdd2a3e59e..47f86d63cf5c 100644
--- a/tests/init/neg/super-resolution.check
+++ b/tests/init/neg/super-resolution.check
@@ -2,35 +2,35 @@
 21 |  val m = 30 // error
    |      ^
    |      Access non-initialized value m. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution.scala:17 ]
-   |         ^
-   |      -> foo()	[ super-resolution.scala:18 ]
-   |         ^^^^^
-   |      -> override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
-   |                                       ^^^^^^^^^^^
-   |      -> override def foo(): Int = a + super.foo()	[ super-resolution.scala:11 ]
-   |                                       ^^^^^^^^^^^
-   |      -> def foo(): Int = m	[ super-resolution.scala:7 ]
-   |                          ^
+   |      ├── class C extends A with M with N:	[ super-resolution.scala:17 ]
+   |      │   ^
+   |      ├── foo()	[ super-resolution.scala:18 ]
+   |      │   ^^^^^
+   |      ├── override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
+   |      │                                 ^^^^^^^^^^^
+   |      ├── override def foo(): Int = a + super.foo()	[ super-resolution.scala:11 ]
+   |      │                                 ^^^^^^^^^^^
+   |      └── def foo(): Int = m	[ super-resolution.scala:7 ]
+   |                           ^
 -- Error: tests/init/neg/super-resolution.scala:19:6 -------------------------------------------------------------------
 19 |  val a = 10 // error
    |      ^
    |      Access non-initialized value a. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution.scala:17 ]
-   |         ^
-   |      -> foo()	[ super-resolution.scala:18 ]
-   |         ^^^^^
-   |      -> override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
-   |                                       ^^^^^^^^^^^
-   |      -> override def foo(): Int = a + super.foo()	[ super-resolution.scala:11 ]
-   |                                   ^
+   |      ├── class C extends A with M with N:	[ super-resolution.scala:17 ]
+   |      │   ^
+   |      ├── foo()	[ super-resolution.scala:18 ]
+   |      │   ^^^^^
+   |      ├── override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
+   |      │                                 ^^^^^^^^^^^
+   |      └── override def foo(): Int = a + super.foo()	[ super-resolution.scala:11 ]
+   |                                    ^
 -- Error: tests/init/neg/super-resolution.scala:20:6 -------------------------------------------------------------------
 20 |  val b = 20 // error
    |      ^
    |      Access non-initialized value b. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution.scala:17 ]
-   |         ^
-   |      -> foo()	[ super-resolution.scala:18 ]
-   |         ^^^^^
-   |      -> override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
-   |                                   ^
+   |      ├── class C extends A with M with N:	[ super-resolution.scala:17 ]
+   |      │   ^
+   |      ├── foo()	[ super-resolution.scala:18 ]
+   |      │   ^^^^^
+   |      └── override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
+   |                                    ^
diff --git a/tests/init/neg/super-resolution2.check b/tests/init/neg/super-resolution2.check
index f852c519e922..7e8cca7690b1 100644
--- a/tests/init/neg/super-resolution2.check
+++ b/tests/init/neg/super-resolution2.check
@@ -2,27 +2,27 @@
 19 |  val n = 40 // error
    |      ^
    |      Access non-initialized value n. Calling trace:
-   |      -> class N extends A with B:	[ super-resolution2.scala:9 ]
-   |         ^
-   |      -> new Inner	[ super-resolution2.scala:16 ]
-   |         ^^^^^^^^^
-   |      -> class Inner:	[ super-resolution2.scala:12 ]
-   |         ^
-   |      -> N.super[A].foo()	[ super-resolution2.scala:13 ]
-   |         ^^^^^^^^^^^^^^^^
-   |      -> def foo(): Int = n	[ super-resolution2.scala:3 ]
-   |                          ^
+   |      ├── class N extends A with B:	[ super-resolution2.scala:9 ]
+   |      │   ^
+   |      ├── new Inner	[ super-resolution2.scala:16 ]
+   |      │   ^^^^^^^^^
+   |      ├── class Inner:	[ super-resolution2.scala:12 ]
+   |      │   ^
+   |      ├── N.super[A].foo()	[ super-resolution2.scala:13 ]
+   |      │   ^^^^^^^^^^^^^^^^
+   |      └── def foo(): Int = n	[ super-resolution2.scala:3 ]
+   |                           ^
 -- Error: tests/init/neg/super-resolution2.scala:18:6 ------------------------------------------------------------------
 18 |  val m = 30 // error
    |      ^
    |      Access non-initialized value m. Calling trace:
-   |      -> class N extends A with B:	[ super-resolution2.scala:9 ]
-   |         ^
-   |      -> new Inner	[ super-resolution2.scala:16 ]
-   |         ^^^^^^^^^
-   |      -> class Inner:	[ super-resolution2.scala:12 ]
-   |         ^
-   |      -> N.super.foo()	[ super-resolution2.scala:14 ]
-   |         ^^^^^^^^^^^^^
-   |      -> def foo(): Int = m	[ super-resolution2.scala:7 ]
-   |                          ^
+   |      ├── class N extends A with B:	[ super-resolution2.scala:9 ]
+   |      │   ^
+   |      ├── new Inner	[ super-resolution2.scala:16 ]
+   |      │   ^^^^^^^^^
+   |      ├── class Inner:	[ super-resolution2.scala:12 ]
+   |      │   ^
+   |      ├── N.super.foo()	[ super-resolution2.scala:14 ]
+   |      │   ^^^^^^^^^^^^^
+   |      └── def foo(): Int = m	[ super-resolution2.scala:7 ]
+   |                           ^
diff --git a/tests/init/neg/super-resolution3.check b/tests/init/neg/super-resolution3.check
index 704d64d6d0cd..d23e944c8ee3 100644
--- a/tests/init/neg/super-resolution3.check
+++ b/tests/init/neg/super-resolution3.check
@@ -2,57 +2,57 @@
 27 |  val n = 40 // error
    |      ^
    |      Access non-initialized value n. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution3.scala:22 ]
-   |         ^
-   |      -> new Inner()	[ super-resolution3.scala:23 ]
-   |         ^^^^^^^^^^^
-   |      -> class Inner:	[ super-resolution3.scala:17 ]
-   |         ^
-   |      -> N.super[A].foo()	[ super-resolution3.scala:18 ]
-   |         ^^^^^^^^^^^^^^^^
-   |      -> def foo(): Int = n	[ super-resolution3.scala:3 ]
-   |                          ^
+   |      ├── class C extends A with M with N:	[ super-resolution3.scala:22 ]
+   |      │   ^
+   |      ├── new Inner()	[ super-resolution3.scala:23 ]
+   |      │   ^^^^^^^^^^^
+   |      ├── class Inner:	[ super-resolution3.scala:17 ]
+   |      │   ^
+   |      ├── N.super[A].foo()	[ super-resolution3.scala:18 ]
+   |      │   ^^^^^^^^^^^^^^^^
+   |      └── def foo(): Int = n	[ super-resolution3.scala:3 ]
+   |                           ^
 -- Error: tests/init/neg/super-resolution3.scala:26:6 ------------------------------------------------------------------
 26 |  val m = 30 // error
    |      ^
    |      Access non-initialized value m. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution3.scala:22 ]
-   |         ^
-   |      -> new Inner()	[ super-resolution3.scala:23 ]
-   |         ^^^^^^^^^^^
-   |      -> class Inner:	[ super-resolution3.scala:17 ]
-   |         ^
-   |      -> N.super.foo()	[ super-resolution3.scala:19 ]
-   |         ^^^^^^^^^^^^^
-   |      -> override def foo(): Int = a + super.foo()	[ super-resolution3.scala:11 ]
-   |                                       ^^^^^^^^^^^
-   |      -> def foo(): Int = m	[ super-resolution3.scala:7 ]
-   |                          ^
+   |      ├── class C extends A with M with N:	[ super-resolution3.scala:22 ]
+   |      │   ^
+   |      ├── new Inner()	[ super-resolution3.scala:23 ]
+   |      │   ^^^^^^^^^^^
+   |      ├── class Inner:	[ super-resolution3.scala:17 ]
+   |      │   ^
+   |      ├── N.super.foo()	[ super-resolution3.scala:19 ]
+   |      │   ^^^^^^^^^^^^^
+   |      ├── override def foo(): Int = a + super.foo()	[ super-resolution3.scala:11 ]
+   |      │                                 ^^^^^^^^^^^
+   |      └── def foo(): Int = m	[ super-resolution3.scala:7 ]
+   |                           ^
 -- Error: tests/init/neg/super-resolution3.scala:24:6 ------------------------------------------------------------------
 24 |  val a = 10 // error
    |      ^
    |      Access non-initialized value a. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution3.scala:22 ]
-   |         ^
-   |      -> new Inner()	[ super-resolution3.scala:23 ]
-   |         ^^^^^^^^^^^
-   |      -> class Inner:	[ super-resolution3.scala:17 ]
-   |         ^
-   |      -> N.super.foo()	[ super-resolution3.scala:19 ]
-   |         ^^^^^^^^^^^^^
-   |      -> override def foo(): Int = a + super.foo()	[ super-resolution3.scala:11 ]
-   |                                   ^
+   |      ├── class C extends A with M with N:	[ super-resolution3.scala:22 ]
+   |      │   ^
+   |      ├── new Inner()	[ super-resolution3.scala:23 ]
+   |      │   ^^^^^^^^^^^
+   |      ├── class Inner:	[ super-resolution3.scala:17 ]
+   |      │   ^
+   |      ├── N.super.foo()	[ super-resolution3.scala:19 ]
+   |      │   ^^^^^^^^^^^^^
+   |      └── override def foo(): Int = a + super.foo()	[ super-resolution3.scala:11 ]
+   |                                    ^
 -- Error: tests/init/neg/super-resolution3.scala:25:6 ------------------------------------------------------------------
 25 |  val b = 20 // error
    |      ^
    |      Access non-initialized value b. Calling trace:
-   |      -> class C extends A with M with N:	[ super-resolution3.scala:22 ]
-   |         ^
-   |      -> new Inner()	[ super-resolution3.scala:23 ]
-   |         ^^^^^^^^^^^
-   |      -> class Inner:	[ super-resolution3.scala:17 ]
-   |         ^
-   |      -> foo()	[ super-resolution3.scala:20 ]
-   |         ^^^^^
-   |      -> override def foo(): Int = b * super.foo()	[ super-resolution3.scala:15 ]
-   |                                   ^
+   |      ├── class C extends A with M with N:	[ super-resolution3.scala:22 ]
+   |      │   ^
+   |      ├── new Inner()	[ super-resolution3.scala:23 ]
+   |      │   ^^^^^^^^^^^
+   |      ├── class Inner:	[ super-resolution3.scala:17 ]
+   |      │   ^
+   |      ├── foo()	[ super-resolution3.scala:20 ]
+   |      │   ^^^^^
+   |      └── override def foo(): Int = b * super.foo()	[ super-resolution3.scala:15 ]
+   |                                    ^
diff --git a/tests/init/neg/t3273.check b/tests/init/neg/t3273.check
index 0fe7ea78871c..85414ff7e592 100644
--- a/tests/init/neg/t3273.check
+++ b/tests/init/neg/t3273.check
@@ -2,25 +2,25 @@
 4 |  val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error
   |                                  ^^^^^^^^^^^^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be a function where "this" is (the original object of type (object Test) where initialization checking started). Only transitively initialized arguments may be passed to methods (except constructors). Calling trace:
-  |-> object Test {	[ t3273.scala:3 ]
-  |   ^
-  |-> val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
-  |                                   ^^^^^^^^^^^^^^^
+  |├── object Test {	[ t3273.scala:3 ]
+  |│   ^
+  |└── val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
+  |                                    ^^^^^^^^^^^^^^^
   |
   |Promoting the value to transitively initialized (Hot) failed due to the following problem:
   |Access non-initialized value num1. Promotion trace:
-  |-> val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
-  |                                   ^^^^
+  |└── val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
+  |                                    ^^^^
 -- Error: tests/init/neg/t3273.scala:5:61 ------------------------------------------------------------------------------
 5 |  val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error
   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |Could not verify that the method argument is transitively initialized (Hot). It was found to be a function where "this" is (the original object of type (object Test) where initialization checking started). Only transitively initialized arguments may be passed to methods (except constructors). Calling trace:
-  |-> object Test {	[ t3273.scala:3 ]
-  |   ^
-  |-> val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error	[ t3273.scala:5 ]
-  |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |├── object Test {	[ t3273.scala:3 ]
+  |│   ^
+  |└── val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error	[ t3273.scala:5 ]
+  |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   |Promoting the value to transitively initialized (Hot) failed due to the following problem:
   |Access non-initialized value num2. Promotion trace:
-  |-> val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error	[ t3273.scala:5 ]
-  |                                   ^^^^
+  |└── val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error	[ t3273.scala:5 ]
+  |                                    ^^^^
diff --git a/tests/init/neg/unsound1.check b/tests/init/neg/unsound1.check
index d114ba072db6..ef3ad1de7728 100644
--- a/tests/init/neg/unsound1.check
+++ b/tests/init/neg/unsound1.check
@@ -2,7 +2,7 @@
 2 |  if (m > 0) println(foo(m - 1).a2.n) // error
   |                     ^^^^^^^^^^^^^^^
   |                     Access field variable n on an uninitialized (Cold) object. Calling trace:
-  |                     -> class A(m: Int) {	[ unsound1.scala:1 ]
-  |                        ^
-  |                     -> if (m > 0) println(foo(m - 1).a2.n) // error	[ unsound1.scala:2 ]
-  |                                           ^^^^^^^^^^^^^^^
+  |                     ├── class A(m: Int) {	[ unsound1.scala:1 ]
+  |                     │   ^
+  |                     └── if (m > 0) println(foo(m - 1).a2.n) // error	[ unsound1.scala:2 ]
+  |                                            ^^^^^^^^^^^^^^^
diff --git a/tests/init/neg/unsound2.check b/tests/init/neg/unsound2.check
index 69d1278e94df..d1525ca9d18c 100644
--- a/tests/init/neg/unsound2.check
+++ b/tests/init/neg/unsound2.check
@@ -1,12 +1,12 @@
 -- Error: tests/init/neg/unsound2.scala:5:26 ---------------------------------------------------------------------------
 5 |        def getN: Int = a.n // error
   |                        ^^^
-  |   Access field value n on an uninitialized (Cold) object. Calling trace:
-  |   -> case class A(x: Int) {	[ unsound2.scala:1 ]
-  |      ^
-  |   -> println(foo(x).getB)	[ unsound2.scala:8 ]
-  |              ^^^^^^
-  |   -> def foo(y: Int): B = if (y > 10) then B(bar(y - 1), foo(y - 1).getN) else B(bar(y), 10)	[ unsound2.scala:2 ]
-  |                                                          ^^^^^^^^^^^^^^^
-  |   -> def getN: Int = a.n // error	[ unsound2.scala:5 ]
+  |  Access field value n on an uninitialized (Cold) object. Calling trace:
+  |  ├── case class A(x: Int) {	[ unsound2.scala:1 ]
+  |  │   ^
+  |  ├── println(foo(x).getB)	[ unsound2.scala:8 ]
+  |  │           ^^^^^^
+  |  ├── def foo(y: Int): B = if (y > 10) then B(bar(y - 1), foo(y - 1).getN) else B(bar(y), 10)	[ unsound2.scala:2 ]
+  |  │                                                       ^^^^^^^^^^^^^^^
+  |  └── def getN: Int = a.n // error	[ unsound2.scala:5 ]
   |                      ^^^
diff --git a/tests/init/neg/unsound3.check b/tests/init/neg/unsound3.check
index c32e66272d1a..1cc6e270dbd9 100644
--- a/tests/init/neg/unsound3.check
+++ b/tests/init/neg/unsound3.check
@@ -2,11 +2,11 @@
 10 |        if (x < 12) then foo().getC().b else newB // error
    |                         ^^^^^^^^^^^^^^
    |                         Access field value b on an uninitialized (Cold) object. Calling trace:
-   |                         -> class C {	[ unsound3.scala:5 ]
-   |                            ^
-   |                         -> val b = foo()	[ unsound3.scala:12 ]
-   |                                    ^^^^^
-   |                         -> def foo(): B = {	[ unsound3.scala:7 ]
-   |                            ^
-   |                         -> if (x < 12) then foo().getC().b else newB // error	[ unsound3.scala:10 ]
-   |                                             ^^^^^^^^^^^^^^
+   |                         ├── class C {	[ unsound3.scala:5 ]
+   |                         │   ^
+   |                         ├── val b = foo()	[ unsound3.scala:12 ]
+   |                         │           ^^^^^
+   |                         ├── def foo(): B = {	[ unsound3.scala:7 ]
+   |                         │   ^
+   |                         └── if (x < 12) then foo().getC().b else newB // error	[ unsound3.scala:10 ]
+   |                                              ^^^^^^^^^^^^^^
diff --git a/tests/init/neg/unsound4.check b/tests/init/neg/unsound4.check
index 9b356b35a3c2..fb9a99cf9bea 100644
--- a/tests/init/neg/unsound4.check
+++ b/tests/init/neg/unsound4.check
@@ -2,9 +2,9 @@
 3 |    val aAgain = foo(5) // error
   |        ^
   |        Access non-initialized value aAgain. Calling trace:
-  |        -> class A {	[ unsound4.scala:1 ]
-  |           ^
-  |        -> val aAgain = foo(5) // error	[ unsound4.scala:3 ]
-  |                        ^^^^^^
-  |        -> def foo(x: Int): A = if (x < 5) then this else foo(x - 1).aAgain	[ unsound4.scala:2 ]
-  |                                                          ^^^^^^^^^^^^^^^^^
+  |        ├── class A {	[ unsound4.scala:1 ]
+  |        │   ^
+  |        ├── val aAgain = foo(5) // error	[ unsound4.scala:3 ]
+  |        │                ^^^^^^
+  |        └── def foo(x: Int): A = if (x < 5) then this else foo(x - 1).aAgain	[ unsound4.scala:2 ]
+  |                                                           ^^^^^^^^^^^^^^^^^