diff --git a/tests/functional/repl_characterization/data/stack_vars.test b/tests/functional/repl_characterization/data/stack_vars.test
deleted file mode 100644
index bd845087c..000000000
--- a/tests/functional/repl_characterization/data/stack_vars.test
+++ /dev/null
@@ -1,108 +0,0 @@
-@args --debugger
-  trace: before outer break
-  info: breakpoint reached
-
-Here we are in the outer break and the let of "meow". st should show meow there
-as it is in scope.
-  nix-repl> :st
-
-  0: error: breakpoint reached
-  $TEST_DATA/stack_vars.nix:6:22
-
-       5|   b = builtins.trace "before outer break" (
-       6|     let meow = 2; in builtins.break a
-        |                      ^
-       7|   );
-
-  Env level 0
-  static: meow
-
-  Env level 1
-  static: a b
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  nix-repl> meow
-  2
-
-If we :st past the frame in the backtrace with the meow in it, the meow should not be there.
-
-  nix-repl> :st 3
-
-  3: while calling a function
-  $TEST_DATA/stack_vars.nix:5:7
-
-       4|   );
-       5|   b = builtins.trace "before outer break" (
-        |       ^
-       6|     let meow = 2; in builtins.break a
-
-  Env level 0
-  static: a b
-
-  Env level 1
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  nix-repl> :c
-  trace: before inner break
-  info: breakpoint reached
-
-  nix-repl> :st
-
-  0: error: breakpoint reached
-  $TEST_DATA/stack_vars.nix:3:23
-
-       2|   a = builtins.trace "before inner break" (
-       3|     let meow' = 3; in builtins.break { msg = "hello"; }
-        |                       ^
-       4|   );
-
-  Env level 0
-  static: meow'
-
-  Env level 1
-  static: a b
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  nix-repl> meow'
-  3
-
-  nix-repl> :st 3
-  3: while calling a function
-  $TEST_DATA/stack_vars.nix:2:7
-
-       1| let
-       2|   a = builtins.trace "before inner break" (
-        |       ^
-       3|     let meow' = 3; in builtins.break { msg = "hello"; }
-
-  Env level 0
-  static: a b
-
-  Env level 1
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  nix-repl> :quit
-  error:
-         … while evaluating the file '$TEST_DATA/stack_vars.nix':
-
-         … while evaluating b
-           at $TEST_DATA/stack_vars.nix:9:3:
-              8| in
-              9|   b
-               |   ^
-             10|
-
-         … while calling the 'trace' builtin
-           at $TEST_DATA/stack_vars.nix:5:7:
-              4|   );
-              5|   b = builtins.trace "before outer break" (
-               |       ^
-              6|     let meow = 2; in builtins.break a
-
-         (stack trace truncated; use '--show-trace' to show the full trace)
-
-         error: breakpoint reached
diff --git a/tests/functional/repl_characterization/data/stacktrace_invalid_arg.test b/tests/functional/repl_characterization/data/stacktrace_invalid_arg.test
deleted file mode 100644
index 39c3350e2..000000000
--- a/tests/functional/repl_characterization/data/stacktrace_invalid_arg.test
+++ /dev/null
@@ -1,73 +0,0 @@
-@args --debugger
-  nix-repl> throw "(forever?????????)"
-  error: (forever?????????)
-
-argument-less :st works fine
-  nix-repl> :st
-
-  0: error: (forever?????????)
-  «string»:1:1
-
-       1| throw "(forever?????????)"
-        | ^
-
-  Env level 0
-  static:
-
-  Env level 1
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-a non-numeric strings produces an error
-  nix-repl> :st chat
-  error: argument 'chat' is not a valid integer
-
-  nix-repl> :st bedroom community
-  error: argument 'bedroom community' is not a valid integer
-
-...even when they start with a digit
-  nix-repl> :st 6up
-  error: argument '6up' is not a valid integer
-
-...or when they're floats
-  nix-repl> :st 4.50
-  error: argument '4.50' is not a valid integer
-
-an integer outside the range produces an error
-  nix-repl> :st 23571113171923
-  error: argument '23571113171923' is not a valid integer
-
-argument-less :st is still at the same index after errors
-  nix-repl> :st 1
-
-  1: while calling a function
-  «string»:1:1
-
-       1| throw "(forever?????????)"
-        | ^
-
-  Env level 0
-  static:
-
-  Env level 1
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  nix-repl> :st foo
-  error: argument 'foo' is not a valid integer
-
-  nix-repl> :st
-
-  1: while calling a function
-  «string»:1:1
-
-       1| throw "(forever?????????)"
-        | ^
-
-  Env level 0
-  static:
-
-  Env level 1
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-quit
-  nix-repl> :quit
-  error: (forever?????????)
diff --git a/tests/functional/repl_characterization/data/stacktrace_oob.test b/tests/functional/repl_characterization/data/stacktrace_oob.test
deleted file mode 100644
index a50f3489e..000000000
--- a/tests/functional/repl_characterization/data/stacktrace_oob.test
+++ /dev/null
@@ -1,110 +0,0 @@
-@args --debugger
-  nix-repl> let f = _: throw "x_x"; x = f 5; in x
-  error: x_x
-
-frames from 0 up to 4 work fine
-  nix-repl> :st 0
-
-  0: error: x_x
-  «string»:1:12
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        |            ^
-
-  Env level 0
-  static: _
-
-  Env level 1
-  static: f x
-
-  Env level 2
-  static:
-
-  Env level 3
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  nix-repl> :st 4
-
-  4: while evaluating a 'let' expression
-  «string»:1:1
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        | ^
-
-  Env level 0
-  static: f x
-
-  Env level 1
-  static:
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-absolute frames out of bounds print an error
-  nix-repl> :st 5
-  error: stack index must be between 0 and 4 (inclusive), but was 5
-
-argument-less :st is still at the same after absolute oob
-  nix-repl> :st
-
-  4: while evaluating a 'let' expression
-  «string»:1:1
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        | ^
-
-  Env level 0
-  static: f x
-
-  Env level 1
-  static:
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-positive relative frames oob clamp to upper bound and print a warning
-  nix-repl> :st +5
-
-  4: while evaluating a 'let' expression
-  «string»:1:1
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        | ^
-
-  Env level 0
-  static: f x
-
-  Env level 1
-  static:
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  warning: stopped at stack frame 4, cannot go any higher
-
-negative relative frames oob clamp to lower bound and print a warning
-  nix-repl> :st -5
-
-  0: error: x_x
-  «string»:1:12
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        |            ^
-
-  Env level 0
-  static: _
-
-  Env level 1
-  static: f x
-
-  Env level 2
-  static:
-
-  Env level 3
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-  warning: stopped at stack frame 0, cannot go any deeper
-
-quit
-  nix-repl> :quit
-  error: x_x
diff --git a/tests/functional/repl_characterization/data/stacktrace_relative.test b/tests/functional/repl_characterization/data/stacktrace_relative.test
deleted file mode 100644
index 2728a18ca..000000000
--- a/tests/functional/repl_characterization/data/stacktrace_relative.test
+++ /dev/null
@@ -1,64 +0,0 @@
-@args --debugger
-  nix-repl> let f = _: throw "x_x"; x = f 5; in x
-  error: x_x
-
-absolute indices still work:
-  nix-repl> :st 1
-
-  1: while calling a function
-  «string»:1:12
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        |            ^
-
-  Env level 0
-  static: _
-
-  Env level 1
-  static: f x
-
-  Env level 2
-  static:
-
-  Env level 3
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-index with + goes up the stack relative to current (1 in this case):
-  nix-repl> :st +3
-
-  4: while evaluating a 'let' expression
-  «string»:1:1
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        | ^
-
-  Env level 0
-  static: f x
-
-  Env level 1
-  static:
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-index with - goes down and is also relative to current (4):
-  nix-repl> :st -1
-
-  3: while calling a function
-  «string»:1:29
-
-       1| let f = _: throw "x_x"; x = f 5; in x
-        |                             ^
-
-  Env level 0
-  static: f x
-
-  Env level 1
-  static:
-
-  Env level 2
-  abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true
-
-quit
-  nix-repl> :quit
-  error: x_x
diff --git a/tests/functional/repl_characterization/repl_characterization.cc b/tests/functional/repl_characterization/repl_characterization.cc
index c2a61e580..49a195fcb 100644
--- a/tests/functional/repl_characterization/repl_characterization.cc
+++ b/tests/functional/repl_characterization/repl_characterization.cc
@@ -176,9 +176,4 @@ TEST_F(ReplSessionTest, tidy)
         runReplTestPath(#name);   \
     }
 
-REPL_TEST(stack_vars);
-REPL_TEST(stacktrace_invalid_arg);
-REPL_TEST(stacktrace_oob);
-REPL_TEST(stacktrace_relative);
-
 }; // namespace nix
diff --git a/tests/functional2/repl_characterization/stacktrace/invalid_arg.md b/tests/functional2/repl_characterization/stacktrace/invalid_arg.md
new file mode 100644
index 000000000..32edfb84a
--- /dev/null
+++ b/tests/functional2/repl_characterization/stacktrace/invalid_arg.md
@@ -0,0 +1,127 @@
+---
+args: ['--debugger']
+---
+
+```nix
+throw "(forever????????)"
+```
+```output
+error: (forever????????)
+
+```
+
+
+argument-less :st works fine
+
+```nix
+:st
+```
+```output
+
+0: error: (forever????????)
+«string»:1:1
+
+     1| throw "(forever????????)"
+      | ^
+
+Env level 0
+static: 
+
+Env level 1
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+```
+
+
+a non-numeric string produces an error
+
+```nix
+:st chat
+:st bedroom community
+```
+```output
+error: argument 'chat' is not a valid integer
+
+error: argument 'bedroom community' is not a valid integer
+
+```
+
+
+even when they start with a digit
+```nix
+:st 6up
+```
+```output
+error: argument '6up' is not a valid integer
+
+```
+
+
+or when they're floats
+```nix
+:st 4.50
+```
+```output
+error: argument '4.50' is not a valid integer
+
+```
+
+
+
+an integer outside of the  range produces an error
+```nix
+:st 23571113171923
+```
+```output
+error: argument '23571113171923' is not a valid integer
+
+```
+
+
+argument-less `:st` is still at the same index after errors
+```nix
+:st 1
+:st foo
+:st
+```
+```output
+
+1: while calling a function
+«string»:1:1
+
+     1| throw "(forever????????)"
+      | ^
+
+Env level 0
+static: 
+
+Env level 1
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+
+error: argument 'foo' is not a valid integer
+
+
+1: while calling a function
+«string»:1:1
+
+     1| throw "(forever????????)"
+      | ^
+
+Env level 0
+static: 
+
+Env level 1
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+```
+
+
+quit
+```nix
+:quit
+```
+```output
+error: (forever????????)
+
+```
diff --git a/tests/functional2/repl_characterization/stacktrace/oob.md b/tests/functional2/repl_characterization/stacktrace/oob.md
new file mode 100644
index 000000000..02628dfc3
--- /dev/null
+++ b/tests/functional2/repl_characterization/stacktrace/oob.md
@@ -0,0 +1,165 @@
+---
+args: ['--debugger']
+---
+
+```nix
+let f = _: throw "x_x"; x = f 5; in x
+```
+```output
+error: x_x
+
+Added 3 variables.
+```
+
+
+
+frames from 0 up to 4 work fine
+```nix
+:st 0
+:st 4
+```
+```output
+
+0: error: x_x
+«string»:1:12
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      |            ^
+
+Env level 0
+static: _ 
+
+Env level 1
+static: f x 
+
+Env level 2
+static: 
+
+Env level 3
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 3 variables.
+
+
+4: while evaluating a 'let' expression
+«string»:1:1
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      | ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+absolute frames out of bounds print an error
+```nix
+:st 5
+```
+```output
+error: stack index must be between 0 and 4 (inclusive), but was 5
+
+```
+
+
+argument-less `:st` is still the same afer absolute oob
+```nix
+:st
+```
+```output
+
+4: while evaluating a 'let' expression
+«string»:1:1
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      | ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+positive relative frames oob clamp to upper bound and prints a warning
+```nix
+:st +5
+```
+```output
+
+4: while evaluating a 'let' expression
+«string»:1:1
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      | ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+warning: stopped at stack frame 4, cannot go any higher
+
+```
+
+
+negative relative frames oob clamp to lower bound and print a warning
+```nix
+:st -5
+```
+```output
+
+0: error: x_x
+«string»:1:12
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      |            ^
+
+Env level 0
+static: _ 
+
+Env level 1
+static: f x 
+
+Env level 2
+static: 
+
+Env level 3
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 3 variables.
+warning: stopped at stack frame 0, cannot go any deeper
+
+```
+
+
+
+quit
+```nix
+:quit
+```
+```output
+error: x_x
+
+```
diff --git a/tests/functional2/repl_characterization/stacktrace/relative.md b/tests/functional2/repl_characterization/stacktrace/relative.md
new file mode 100644
index 000000000..fbc03cdf6
--- /dev/null
+++ b/tests/functional2/repl_characterization/stacktrace/relative.md
@@ -0,0 +1,105 @@
+---
+args: ['--debugger']
+---
+
+```nix
+let f = _: throw "x_x"; x = f 5; in x
+```
+```output
+error: x_x
+
+Added 3 variables.
+```
+
+
+absolute indices still work:
+```nix
+:st 1
+```
+```output
+
+1: while calling a function
+«string»:1:12
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      |            ^
+
+Env level 0
+static: _ 
+
+Env level 1
+static: f x 
+
+Env level 2
+static: 
+
+Env level 3
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 3 variables.
+
+```
+
+
+index with + goes up the stack relative to current (1 in this case):
+```nix
+:st +3
+```
+```output
+
+4: while evaluating a 'let' expression
+«string»:1:1
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      | ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+
+index with - goes down and is also relative to current(4):
+
+```nix
+:st -1
+```
+```output
+
+3: while calling a function
+«string»:1:29
+
+     1| let f = _: throw "x_x"; x = f 5; in x
+      |                             ^
+
+Env level 0
+static: f x 
+
+Env level 1
+static: 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+quit
+```nix
+:quit
+```
+```output
+error: x_x
+
+```
diff --git a/tests/functional/repl_characterization/data/stack_vars.nix b/tests/functional2/repl_characterization/stacktrace/stack_vars.nix
similarity index 100%
rename from tests/functional/repl_characterization/data/stack_vars.nix
rename to tests/functional2/repl_characterization/stacktrace/stack_vars.nix
diff --git a/tests/functional2/repl_characterization/stacktrace/vars.md b/tests/functional2/repl_characterization/stacktrace/vars.md
new file mode 100644
index 000000000..a2a6dee2d
--- /dev/null
+++ b/tests/functional2/repl_characterization/stacktrace/vars.md
@@ -0,0 +1,178 @@
+---
+args: ['--debugger', '-f', '{PWD}/stack_vars.nix']
+should_fail: True
+files: ['stack_vars.nix']
+---
+
+```output
+Lix VERSION
+Type :? for help.
+trace: before outer break
+info: breakpoint reached
+
+Added 3 variables.
+```
+Here we are in the outer break and the let of "meow". `:st` should show meow there
+```nix
+:st
+```
+```output
+
+0: error: breakpoint reached
+/pwd/stack_vars.nix:6:22
+
+     5|   b = builtins.trace "before outer break" (
+     6|     let meow = 2; in builtins.break a
+      |                      ^
+     7|   );
+
+Env level 0
+static: meow 
+
+Env level 1
+static: a b 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 3 variables.
+
+```
+```nix
+meow
+```
+```output
+2
+
+```
+
+
+
+
+If we `:st` past the frame in the backtrace with the `meow` in it, the `meow` should not be there
+```nix
+:st 3
+:c
+```
+```output
+
+3: while calling a function
+/pwd/stack_vars.nix:5:7
+
+     4|   );
+     5|   b = builtins.trace "before outer break" (
+      |       ^
+     6|     let meow = 2; in builtins.break a
+
+Env level 0
+static: a b 
+
+Env level 1
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+trace: before inner break
+info: breakpoint reached
+
+Added 3 variables.
+```
+
+```nix
+:st
+```
+```output
+
+0: error: breakpoint reached
+/pwd/stack_vars.nix:3:23
+
+     2|   a = builtins.trace "before inner break" (
+     3|     let meow' = 3; in builtins.break { msg = "hello"; }
+      |                       ^
+     4|   );
+
+Env level 0
+static: meow' 
+
+Env level 1
+static: a b 
+
+Env level 2
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 3 variables.
+
+```
+
+```nix
+meow'
+:st 3
+```
+```output
+3
+
+
+3: while calling a function
+/pwd/stack_vars.nix:2:7
+
+     1| let
+     2|   a = builtins.trace "before inner break" (
+      |       ^
+     3|     let meow' = 3; in builtins.break { msg = "hello"; }
+
+Env level 0
+static: a b 
+
+Env level 1
+abort baseNameOf break builtins derivation derivationStrict dirOf false fetchGit fetchMercurial fetchTarball fetchTree fromTOML import isNull map null placeholder removeAttrs scopedImport throw toString true 
+
+Added 2 variables.
+
+```
+
+
+
+```nix
+:quit
+```
+```output
+error:
+       … while evaluating the file '/pwd/stack_vars.nix':
+
+       … while evaluating b
+         at /pwd/stack_vars.nix:9:3:
+            8| in
+            9|   b
+             |   ^
+           10|
+
+       … while calling the 'trace' builtin
+         at /pwd/stack_vars.nix:5:7:
+            4|   );
+            5|   b = builtins.trace "before outer break" (
+             |       ^
+            6|     let meow = 2; in builtins.break a
+
+       … while calling the 'break' builtin
+         at /pwd/stack_vars.nix:6:22:
+            5|   b = builtins.trace "before outer break" (
+            6|     let meow = 2; in builtins.break a
+             |                      ^
+            7|   );
+
+       … while calling the 'trace' builtin
+         at /pwd/stack_vars.nix:2:7:
+            1| let
+            2|   a = builtins.trace "before inner break" (
+             |       ^
+            3|     let meow' = 3; in builtins.break { msg = "hello"; }
+
+       … while calling the 'break' builtin
+         at /pwd/stack_vars.nix:3:23:
+            2|   a = builtins.trace "before inner break" (
+            3|     let meow' = 3; in builtins.break { msg = "hello"; }
+             |                       ^
+            4|   );
+
+       error: breakpoint reached
+```