diff --git a/guppylang/src/guppylang/std/builtins.py b/guppylang/src/guppylang/std/builtins.py
index f3aa05346..8495be6a4 100644
--- a/guppylang/src/guppylang/std/builtins.py
+++ b/guppylang/src/guppylang/std/builtins.py
@@ -3,7 +3,7 @@
 from guppylang.std.array import ArrayIter, FrozenarrayIter, array, frozenarray
 from guppylang.std.bool import bool
 from guppylang.std.iter import Range, SizedIter, range
-from guppylang.std.lang import comptime, owned, py
+from guppylang.std.lang import comptime, control, dagger, owned, power, py
 from guppylang.std.list import list
 from guppylang.std.mem import mem_swap
 from guppylang.std.num import (
@@ -102,6 +102,8 @@
     "compile",
     "complex",
     "comptime",
+    "control",
+    "dagger",
     "delattr",
     "dict",
     "dir",
@@ -145,6 +147,7 @@
     "owned",
     "panic",
     "pow",
+    "power",
     "print",
     "property",
     "py",
diff --git a/guppylang/src/guppylang/std/lang.py b/guppylang/src/guppylang/std/lang.py
index 697bd5c11..3878eec86 100644
--- a/guppylang/src/guppylang/std/lang.py
+++ b/guppylang/src/guppylang/std/lang.py
@@ -1,9 +1,16 @@
 """Provides Python objects for builtin language keywords."""
 
+from collections.abc import Generator
 from typing import Any, Protocol, TypeVar
 
+from guppylang_internals.error import GuppyComptimeError
+
 T = TypeVar("T")
 
+_MODIFIER_COMPTIME_ERROR = (
+    "The `{modifier}` modifier is not supported in comptime functions"
+)
+
 
 class _Comptime:
     """Dummy class to support `@comptime` annotations and `comptime(...)` expressions"""
@@ -42,3 +49,18 @@ class Copy(Protocol):
 
 class Drop(Protocol):
     """Bound to mark generic type parameters as being implicitly droppable."""
+
+
+def control(*args: Any, **kwargs: Any) -> Generator[None]:
+    """Dummy function to support `with control(...):` blocks in Guppy code."""
+    raise GuppyComptimeError(_MODIFIER_COMPTIME_ERROR.format(modifier="control"))
+
+
+def dagger(*args: Any, **kwargs: Any) -> Generator[None]:
+    """Dummy function to support `with dagger(...):` blocks in Guppy code."""
+    raise GuppyComptimeError(_MODIFIER_COMPTIME_ERROR.format(modifier="dagger"))
+
+
+def power(*args: Any, **kwargs: Any) -> Generator[None]:
+    """Dummy function to support `with power(...):` blocks in Guppy code."""
+    raise GuppyComptimeError(_MODIFIER_COMPTIME_ERROR.format(modifier="power"))
diff --git a/tests/error/modifier_errors/captured_var_inout_own.err b/tests/error/modifier_errors/captured_var_inout_own.err
index 5712e0e6a..b0524f8d0 100644
--- a/tests/error/modifier_errors/captured_var_inout_own.err
+++ b/tests/error/modifier_errors/captured_var_inout_own.err
@@ -1,15 +1,15 @@
-Error: Not owned (at $FILE:14:16)
+Error: Not owned (at $FILE:16:16)
    | 
-12 |     a = qubit()
-13 |     with dagger:
-14 |         discard(a)
+14 |     a = qubit()
+15 |     with dagger:
+16 |         discard(a)
    |                 ^ Function `discard` wants to take ownership of this argument,
    |                   but `__modified__()` doesn't own `a`
 
 Help:
    | 
-11 | def test() -> None:
-12 |     a = qubit()
+13 | def test() -> None:
+14 |     a = qubit()
    |     - Argument `a` is only borrowed. Consider taking ownership:
    |       `a: qubit @owned`
 
diff --git a/tests/error/modifier_errors/captured_var_inout_own.py b/tests/error/modifier_errors/captured_var_inout_own.py
index 211baef94..b183f06c6 100644
--- a/tests/error/modifier_errors/captured_var_inout_own.py
+++ b/tests/error/modifier_errors/captured_var_inout_own.py
@@ -1,5 +1,7 @@
 from guppylang.decorator import guppy
 from guppylang.std.quantum import qubit, owned
+from guppylang.std.builtins import dagger
+
 
 
 @guppy.declare(dagger=True)
diff --git a/tests/error/modifier_errors/captured_var_inout_reassign.err b/tests/error/modifier_errors/captured_var_inout_reassign.err
index 3a8ab0040..bdcf779f8 100644
--- a/tests/error/modifier_errors/captured_var_inout_reassign.err
+++ b/tests/error/modifier_errors/captured_var_inout_reassign.err
@@ -1,8 +1,8 @@
-Error: Drop violation (at $FILE:11:4)
+Error: Drop violation (at $FILE:13:4)
    | 
- 9 | @guppy
-10 | def test() -> None:
-11 |     a = qubit()
+11 | @guppy
+12 | def test() -> None:
+13 |     a = qubit()
    |     ^ Variable `a` with non-droppable type `qubit` is leaked
 
 Help: Make sure that `a` is consumed or returned to avoid the leak
diff --git a/tests/error/modifier_errors/captured_var_inout_reassign.py b/tests/error/modifier_errors/captured_var_inout_reassign.py
index ce78856fd..ad130b537 100644
--- a/tests/error/modifier_errors/captured_var_inout_reassign.py
+++ b/tests/error/modifier_errors/captured_var_inout_reassign.py
@@ -1,5 +1,7 @@
 from guppylang.decorator import guppy
 from guppylang.std.quantum import qubit
+from guppylang.std.builtins import dagger
+
 
 
 @guppy.declare(dagger=True)
diff --git a/tests/error/modifier_errors/ctrl_arg_array_many_arg.py b/tests/error/modifier_errors/ctrl_arg_array_many_arg.py
index a2f179200..f22c02073 100644
--- a/tests/error/modifier_errors/ctrl_arg_array_many_arg.py
+++ b/tests/error/modifier_errors/ctrl_arg_array_many_arg.py
@@ -1,6 +1,6 @@
 from guppylang.decorator import guppy
 from guppylang.std.array import array
-from guppylang.std.builtins import owned
+from guppylang.std.builtins import owned, control
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/ctrl_arg_body_copy.err b/tests/error/modifier_errors/ctrl_arg_body_copy.err
index e5f0d25be..319d464ac 100644
--- a/tests/error/modifier_errors/ctrl_arg_body_copy.err
+++ b/tests/error/modifier_errors/ctrl_arg_body_copy.err
@@ -1,15 +1,15 @@
-Error: Copy violation (at $FILE:12:20)
+Error: Copy violation (at $FILE:13:20)
    | 
-10 | def test() -> None:
-11 |     q = qubit()
-12 |     with control(q, q):
+11 | def test() -> None:
+12 |     q = qubit()
+13 |     with control(q, q):
    |                     ^ Variable `q` with non-copyable type `qubit` cannot be
    |                       borrowed ...
 
 Note:
    | 
-11 |     q = qubit()
-12 |     with control(q, q):
+12 |     q = qubit()
+13 |     with control(q, q):
    |                  - Variable `q` already borrowed here
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/ctrl_arg_body_copy.py b/tests/error/modifier_errors/ctrl_arg_body_copy.py
index 822382867..438d756af 100644
--- a/tests/error/modifier_errors/ctrl_arg_body_copy.py
+++ b/tests/error/modifier_errors/ctrl_arg_body_copy.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control
 from guppylang.std.quantum import qubit, owned
 
 
diff --git a/tests/error/modifier_errors/ctrl_arg_copy.err b/tests/error/modifier_errors/ctrl_arg_copy.err
index c0fc2bd07..37f01f97c 100644
--- a/tests/error/modifier_errors/ctrl_arg_copy.err
+++ b/tests/error/modifier_errors/ctrl_arg_copy.err
@@ -1,15 +1,15 @@
-Error: Copy violation (at $FILE:17:12)
+Error: Copy violation (at $FILE:18:12)
    | 
-15 |     q = qubit()
-16 |     with control(q):
-17 |         use(q)
+16 |     q = qubit()
+17 |     with control(q):
+18 |         use(q)
    |             ^ Variable `q` with non-copyable type `qubit` cannot be
    |               borrowed ...
 
 Note:
    | 
-15 |     q = qubit()
-16 |     with control(q):
+16 |     q = qubit()
+17 |     with control(q):
    |                  - Variable `q` already borrowed here
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/ctrl_arg_copy.py b/tests/error/modifier_errors/ctrl_arg_copy.py
index d306be226..205142e1e 100644
--- a/tests/error/modifier_errors/ctrl_arg_copy.py
+++ b/tests/error/modifier_errors/ctrl_arg_copy.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control
 from guppylang.std.quantum import qubit, owned
 
 
diff --git a/tests/error/modifier_errors/ctrl_arg_not_assigned.err b/tests/error/modifier_errors/ctrl_arg_not_assigned.err
index 93caa595f..f2e25efe5 100644
--- a/tests/error/modifier_errors/ctrl_arg_not_assigned.err
+++ b/tests/error/modifier_errors/ctrl_arg_not_assigned.err
@@ -1,8 +1,8 @@
-Error: Drop violation (at $FILE:7:17)
+Error: Drop violation (at $FILE:8:17)
   | 
-5 | @guppy
-6 | def test() -> None:
-7 |     with control(qubit()):
+6 | @guppy
+7 | def test() -> None:
+8 |     with control(qubit()):
   |                  ^^^^^^^ Expression with non-droppable type `qubit` is leaked
 
 Help: Consider assigning this value to a local variable
diff --git a/tests/error/modifier_errors/ctrl_arg_not_assigned.py b/tests/error/modifier_errors/ctrl_arg_not_assigned.py
index a833146fe..b7cd5b85f 100644
--- a/tests/error/modifier_errors/ctrl_arg_not_assigned.py
+++ b/tests/error/modifier_errors/ctrl_arg_not_assigned.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/ctrl_arg_type.err b/tests/error/modifier_errors/ctrl_arg_type.err
index 439e0732f..539809c2a 100644
--- a/tests/error/modifier_errors/ctrl_arg_type.err
+++ b/tests/error/modifier_errors/ctrl_arg_type.err
@@ -1,8 +1,8 @@
-Error: Type mismatch (at $FILE:7:20)
+Error: Type mismatch (at $FILE:9:20)
   | 
-5 | def test() -> None:
-6 |     x = qubit()
-7 |     with control(x, True):
+7 | def test() -> None:
+8 |     x = qubit()
+9 |     with control(x, True):
   |                     ^^^^ Expected expression of type `qubit`, got `bool`
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/ctrl_arg_type.py b/tests/error/modifier_errors/ctrl_arg_type.py
index 31b59604f..277d255c0 100644
--- a/tests/error/modifier_errors/ctrl_arg_type.py
+++ b/tests/error/modifier_errors/ctrl_arg_type.py
@@ -1,4 +1,6 @@
 from guppylang.decorator import guppy
+from guppylang.std.quantum import qubit
+from guppylang.std.builtins import control
 
 
 @guppy
diff --git a/tests/error/modifier_errors/ctrl_arg_type_arr.err b/tests/error/modifier_errors/ctrl_arg_type_arr.err
index d8e34d63e..b0fe82b99 100644
--- a/tests/error/modifier_errors/ctrl_arg_type_arr.err
+++ b/tests/error/modifier_errors/ctrl_arg_type_arr.err
@@ -1,8 +1,8 @@
-Error: Type mismatch (at $FILE:7:17)
+Error: Type mismatch (at $FILE:9:17)
   | 
-5 | def test() -> None:
-6 |     x = array(1, 2, 3)
-7 |     with control(x):
+7 | def test() -> None:
+8 |     x = array(1, 2, 3)
+9 |     with control(x):
   |                  ^ Expected expression of type `array[qubit, ?n]`, got
   |                    `array[int, 3]`
 
diff --git a/tests/error/modifier_errors/ctrl_arg_type_arr.py b/tests/error/modifier_errors/ctrl_arg_type_arr.py
index 8e02fe80f..9079f97f9 100644
--- a/tests/error/modifier_errors/ctrl_arg_type_arr.py
+++ b/tests/error/modifier_errors/ctrl_arg_type_arr.py
@@ -1,4 +1,6 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import array
+from guppylang.std.builtins import control
 
 
 @guppy
diff --git a/tests/error/modifier_errors/ctrl_no_arg.err b/tests/error/modifier_errors/ctrl_no_arg.err
index 72741f123..a0c9afec5 100644
--- a/tests/error/modifier_errors/ctrl_no_arg.err
+++ b/tests/error/modifier_errors/ctrl_no_arg.err
@@ -1,8 +1,8 @@
-Error: Not enough arguments (at $FILE:8:16)
+Error: Not enough arguments (at $FILE:9:16)
   | 
-6 | @guppy
-7 | def test() -> None:
-8 |     with control():
+7 | @guppy
+8 | def test() -> None:
+9 |     with control():
   |                 ^^ Missing argument (expected 1, got 0)
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/ctrl_no_arg.py b/tests/error/modifier_errors/ctrl_no_arg.py
index 091c88148..b58c5ca61 100644
--- a/tests/error/modifier_errors/ctrl_no_arg.py
+++ b/tests/error/modifier_errors/ctrl_no_arg.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control
 
 
 # `control` is overloaded, so the number of arguments need not be fixed to 1.
diff --git a/tests/error/modifier_errors/dagger_arg.err b/tests/error/modifier_errors/dagger_arg.err
index c34cdefc7..1d2cc40e5 100644
--- a/tests/error/modifier_errors/dagger_arg.err
+++ b/tests/error/modifier_errors/dagger_arg.err
@@ -1,8 +1,8 @@
-Error: Too many arguments (at $FILE:6:16)
+Error: Too many arguments (at $FILE:7:16)
   | 
-4 | @guppy
-5 | def test() -> None:
-6 |     with dagger(1):
+5 | @guppy
+6 | def test() -> None:
+7 |     with dagger(1):
   |                 ^ Unexpected argument (expected 0, got 1)
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/dagger_arg.py b/tests/error/modifier_errors/dagger_arg.py
index 9d151c517..b9ba472ed 100644
--- a/tests/error/modifier_errors/dagger_arg.py
+++ b/tests/error/modifier_errors/dagger_arg.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 
 
 @guppy
diff --git a/tests/error/modifier_errors/dagger_assign.err b/tests/error/modifier_errors/dagger_assign.err
index 05af0c508..cc6034a5c 100644
--- a/tests/error/modifier_errors/dagger_assign.err
+++ b/tests/error/modifier_errors/dagger_assign.err
@@ -1,14 +1,14 @@
-Error: Invalid expression in dagger (at $FILE:7:8)
+Error: Invalid expression in dagger (at $FILE:8:8)
   | 
-5 | def test() -> None:
-6 |     with dagger:
-7 |         a = 3
+6 | def test() -> None:
+7 |     with dagger:
+8 |         a = 3
   |         ^^^^^ Assignment found in a dagger context
 
 Note:
   | 
-5 | def test() -> None:
-6 |     with dagger:
+6 | def test() -> None:
+7 |     with dagger:
   |          ------ dagger modifier is used here
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/dagger_assign.py b/tests/error/modifier_errors/dagger_assign.py
index 5c6918d8b..b64dd0047 100644
--- a/tests/error/modifier_errors/dagger_assign.py
+++ b/tests/error/modifier_errors/dagger_assign.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 
 
 @guppy
diff --git a/tests/error/modifier_errors/dagger_loop.err b/tests/error/modifier_errors/dagger_loop.err
index d0e3d99d6..74a923491 100644
--- a/tests/error/modifier_errors/dagger_loop.err
+++ b/tests/error/modifier_errors/dagger_loop.err
@@ -1,16 +1,16 @@
-Error: Invalid expression in dagger (at $FILE:7:8)
+Error: Invalid expression in dagger (at $FILE:8:8)
   | 
-5 | def test() -> None:
-6 |     with dagger:
-7 |         for _ in range(46):
+6 | def test() -> None:
+7 |     with dagger:
+8 |         for _ in range(46):
   |         ^^^^^^^^^^^^^^^^^^^
-8 |             pass
+9 |             pass
   | ^^^^^^^^^^^^^^^^ Loop found in a dagger context
 
 Note:
   | 
-5 | def test() -> None:
-6 |     with dagger:
+6 | def test() -> None:
+7 |     with dagger:
   |          ------ dagger modifier is used here
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/dagger_loop.py b/tests/error/modifier_errors/dagger_loop.py
index 51d04f439..3e726c1af 100644
--- a/tests/error/modifier_errors/dagger_loop.py
+++ b/tests/error/modifier_errors/dagger_loop.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 
 
 @guppy
diff --git a/tests/error/modifier_errors/flags_nested.err b/tests/error/modifier_errors/flags_nested.err
index b36a0dbc9..4d2cc822a 100644
--- a/tests/error/modifier_errors/flags_nested.err
+++ b/tests/error/modifier_errors/flags_nested.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:15:12)
+Error: Unitary constraint violation (at $FILE:16:12)
    | 
-13 |     with dagger:
-14 |         with power(2):
-15 |             foo(q)
+14 |     with dagger:
+15 |         with power(2):
+16 |             foo(q)
    |             ^^^^^^ This function cannot be called in a dagger context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_nested.py b/tests/error/modifier_errors/flags_nested.py
index 919ee0269..f595e8087 100644
--- a/tests/error/modifier_errors/flags_nested.py
+++ b/tests/error/modifier_errors/flags_nested.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger, power
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/flags_nested_combined_outer.err b/tests/error/modifier_errors/flags_nested_combined_outer.err
index b75cffdcb..9c589c19f 100644
--- a/tests/error/modifier_errors/flags_nested_combined_outer.err
+++ b/tests/error/modifier_errors/flags_nested_combined_outer.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:15:12)
+Error: Unitary constraint violation (at $FILE:16:12)
    | 
-13 |     with control(ctrl), dagger:
-14 |         with power(2):
-15 |             foo(q)
+14 |     with control(ctrl), dagger:
+15 |         with power(2):
+16 |             foo(q)
    |             ^^^^^^ This function cannot be called in a unitary context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_nested_combined_outer.py b/tests/error/modifier_errors/flags_nested_combined_outer.py
index 6bf57a4ed..bf4e90024 100644
--- a/tests/error/modifier_errors/flags_nested_combined_outer.py
+++ b/tests/error/modifier_errors/flags_nested_combined_outer.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control, dagger, power
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/flags_nested_control_dagger.err b/tests/error/modifier_errors/flags_nested_control_dagger.err
index 6b300ef35..d55ad0ed9 100644
--- a/tests/error/modifier_errors/flags_nested_control_dagger.err
+++ b/tests/error/modifier_errors/flags_nested_control_dagger.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:15:12)
+Error: Unitary constraint violation (at $FILE:16:12)
    | 
-13 |     with control(ctrl):
-14 |         with dagger:
-15 |             foo(q)
+14 |     with control(ctrl):
+15 |         with dagger:
+16 |             foo(q)
    |             ^^^^^^ This function cannot be called in a dagger context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_nested_control_dagger.py b/tests/error/modifier_errors/flags_nested_control_dagger.py
index 3406fc965..9b24a59bf 100644
--- a/tests/error/modifier_errors/flags_nested_control_dagger.py
+++ b/tests/error/modifier_errors/flags_nested_control_dagger.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control, dagger
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/flags_nested_missing_power.err b/tests/error/modifier_errors/flags_nested_missing_power.err
index f2c7e215c..5872a198f 100644
--- a/tests/error/modifier_errors/flags_nested_missing_power.err
+++ b/tests/error/modifier_errors/flags_nested_missing_power.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:15:12)
+Error: Unitary constraint violation (at $FILE:16:12)
    | 
-13 |     with dagger:
-14 |         with power(2):
-15 |             foo(q)
+14 |     with dagger:
+15 |         with power(2):
+16 |             foo(q)
    |             ^^^^^^ This function cannot be called in a power context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_nested_missing_power.py b/tests/error/modifier_errors/flags_nested_missing_power.py
index 73762d383..a7da17131 100644
--- a/tests/error/modifier_errors/flags_nested_missing_power.py
+++ b/tests/error/modifier_errors/flags_nested_missing_power.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger, power
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/flags_nested_power_control.err b/tests/error/modifier_errors/flags_nested_power_control.err
index 5cc85ad87..ce0d32151 100644
--- a/tests/error/modifier_errors/flags_nested_power_control.err
+++ b/tests/error/modifier_errors/flags_nested_power_control.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:15:12)
+Error: Unitary constraint violation (at $FILE:16:12)
    | 
-13 |     with power(2):
-14 |         with control(ctrl):
-15 |             foo(q)
+14 |     with power(2):
+15 |         with control(ctrl):
+16 |             foo(q)
    |             ^^^^^^ This function cannot be called in a control context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_nested_power_control.py b/tests/error/modifier_errors/flags_nested_power_control.py
index ee61a0ea9..ace251591 100644
--- a/tests/error/modifier_errors/flags_nested_power_control.py
+++ b/tests/error/modifier_errors/flags_nested_power_control.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control, power
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/flags_nested_triple.err b/tests/error/modifier_errors/flags_nested_triple.err
index 10547ad1c..8e41aaaed 100644
--- a/tests/error/modifier_errors/flags_nested_triple.err
+++ b/tests/error/modifier_errors/flags_nested_triple.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:15:16)
+Error: Unitary constraint violation (at $FILE:16:16)
    | 
-13 |         with control(ctrl):
-14 |             with power(2):
-15 |                 foo(q)
+14 |         with control(ctrl):
+15 |             with power(2):
+16 |                 foo(q)
    |                 ^^^^^^ This function cannot be called in a unitary context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_nested_triple.py b/tests/error/modifier_errors/flags_nested_triple.py
index 65bd1d91d..e3a65616a 100644
--- a/tests/error/modifier_errors/flags_nested_triple.py
+++ b/tests/error/modifier_errors/flags_nested_triple.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control, dagger, power
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/flags_triple_dagger.err b/tests/error/modifier_errors/flags_triple_dagger.err
index f851fb4df..8a1b5ed4d 100644
--- a/tests/error/modifier_errors/flags_triple_dagger.err
+++ b/tests/error/modifier_errors/flags_triple_dagger.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:12:8)
+Error: Unitary constraint violation (at $FILE:13:8)
    | 
-10 | def test(q: qubit) -> None:
-11 |     with dagger, dagger, dagger:
-12 |         foo(q)
+11 | def test(q: qubit) -> None:
+12 |     with dagger, dagger, dagger:
+13 |         foo(q)
    |         ^^^^^^ This function cannot be called in a dagger context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/flags_triple_dagger.py b/tests/error/modifier_errors/flags_triple_dagger.py
index c8a6362b7..5c677304d 100644
--- a/tests/error/modifier_errors/flags_triple_dagger.py
+++ b/tests/error/modifier_errors/flags_triple_dagger.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 from guppylang.std.quantum import qubit
 
 
diff --git a/tests/error/modifier_errors/higher_order.err b/tests/error/modifier_errors/higher_order.err
index 94f82424b..59b4662d3 100644
--- a/tests/error/modifier_errors/higher_order.err
+++ b/tests/error/modifier_errors/higher_order.err
@@ -1,8 +1,8 @@
-Error: Unitary constraint violation (at $FILE:10:4)
+Error: Unitary constraint violation (at $FILE:11:4)
    | 
- 8 | def test_ho(f: Callable[[qubit], None], q: qubit) -> None:
- 9 |     # There is no way to use specify flags for f
-10 |     f(q)
+ 9 | def test_ho(f: Callable[[qubit], None], q: qubit) -> None:
+10 |     # There is no way to use specify flags for f
+11 |     f(q)
    |     ^^^^ This function cannot be called in a dagger context
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/higher_order.py b/tests/error/modifier_errors/higher_order.py
index 87148ee84..d35e25bcf 100644
--- a/tests/error/modifier_errors/higher_order.py
+++ b/tests/error/modifier_errors/higher_order.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 from guppylang.std.quantum import qubit, h, discard
 from collections.abc import Callable
 
diff --git a/tests/error/modifier_errors/linear_check_in_block.err b/tests/error/modifier_errors/linear_check_in_block.err
index ed400434c..096ae6d41 100644
--- a/tests/error/modifier_errors/linear_check_in_block.err
+++ b/tests/error/modifier_errors/linear_check_in_block.err
@@ -1,15 +1,15 @@
-Error: Copy violation (at $FILE:15:16)
+Error: Copy violation (at $FILE:16:16)
    | 
-13 |     with control(q):
-14 |         xs = array(1, 2, 3)
-15 |         foo(xs, xs)
+14 |     with control(q):
+15 |         xs = array(1, 2, 3)
+16 |         foo(xs, xs)
    |                 ^^ Variable `xs` with non-copyable type `array[int, 3]` cannot
    |                    be borrowed ...
 
 Note:
    | 
-14 |         xs = array(1, 2, 3)
-15 |         foo(xs, xs)
+15 |         xs = array(1, 2, 3)
+16 |         foo(xs, xs)
    |             -- Variable `xs` already borrowed here
 
 Help: Consider copying `xs` instead of moving it: `xs.copy()`
diff --git a/tests/error/modifier_errors/linear_check_in_block.py b/tests/error/modifier_errors/linear_check_in_block.py
index 306e96876..f42709b45 100644
--- a/tests/error/modifier_errors/linear_check_in_block.py
+++ b/tests/error/modifier_errors/linear_check_in_block.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import control
 from guppylang.std.quantum import qubit
 from guppylang.std.array import array
 
diff --git a/tests/error/modifier_errors/loop_control_found.err b/tests/error/modifier_errors/loop_control_found.err
index dd1ede98d..62db0845b 100644
--- a/tests/error/modifier_errors/loop_control_found.err
+++ b/tests/error/modifier_errors/loop_control_found.err
@@ -1,14 +1,14 @@
-Error: Unexpected loop control (at $FILE:8:12)
+Error: Unexpected loop control (at $FILE:9:12)
   | 
-6 |     for i in range(123):
-7 |         with dagger:
-8 |             continue
+7 |     for i in range(123):
+8 |         with dagger:
+9 |             continue
   |             ^^^^^^^^ Continue found in a `With` block
 
 Note:
   | 
-6 |     for i in range(123):
-7 |         with dagger:
+7 |     for i in range(123):
+8 |         with dagger:
   |              ------ modifier is used here
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/loop_control_found.py b/tests/error/modifier_errors/loop_control_found.py
index a62f97ebb..cfb9e78fe 100644
--- a/tests/error/modifier_errors/loop_control_found.py
+++ b/tests/error/modifier_errors/loop_control_found.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 
 
 @guppy
diff --git a/tests/error/modifier_errors/optional_as_found.err b/tests/error/modifier_errors/optional_as_found.err
index 970779c0c..39c3216f0 100644
--- a/tests/error/modifier_errors/optional_as_found.err
+++ b/tests/error/modifier_errors/optional_as_found.err
@@ -1,8 +1,8 @@
-Error: Unsupported (at $FILE:6:9)
+Error: Unsupported (at $FILE:7:9)
   | 
-4 | @guppy
-5 | def test() -> None:
-6 |     with power(1) as x:
+5 | @guppy
+6 | def test() -> None:
+7 |     with power(1) as x:
   |          ^^^^^^^^^^^^^ `as` expression is not supported
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/optional_as_found.py b/tests/error/modifier_errors/optional_as_found.py
index 0810a0a1b..98889d793 100644
--- a/tests/error/modifier_errors/optional_as_found.py
+++ b/tests/error/modifier_errors/optional_as_found.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import power
 
 
 @guppy
diff --git a/tests/error/modifier_errors/power_arg_type.err b/tests/error/modifier_errors/power_arg_type.err
index 24dafa4d5..092ae66d0 100644
--- a/tests/error/modifier_errors/power_arg_type.err
+++ b/tests/error/modifier_errors/power_arg_type.err
@@ -1,8 +1,8 @@
-Error: Type mismatch (at $FILE:6:15)
+Error: Type mismatch (at $FILE:7:15)
   | 
-4 | @guppy
-5 | def test() -> None:
-6 |     with power(0.3):
+5 | @guppy
+6 | def test() -> None:
+7 |     with power(0.3):
   |                ^^^ Expected expression of type `nat`, got `float`
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/power_arg_type.py b/tests/error/modifier_errors/power_arg_type.py
index d2389206c..2fdb81e73 100644
--- a/tests/error/modifier_errors/power_arg_type.py
+++ b/tests/error/modifier_errors/power_arg_type.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import power
 
 
 @guppy
diff --git a/tests/error/modifier_errors/power_arg_typecheck_inside.err b/tests/error/modifier_errors/power_arg_typecheck_inside.err
index 5e485a26d..da79c3be4 100644
--- a/tests/error/modifier_errors/power_arg_typecheck_inside.err
+++ b/tests/error/modifier_errors/power_arg_typecheck_inside.err
@@ -1,8 +1,8 @@
-Error: Operator not defined (at $FILE:6:15)
+Error: Operator not defined (at $FILE:7:15)
   | 
-4 | @guppy
-5 | def test() -> None:
-6 |     with power(12 + False):
+5 | @guppy
+6 | def test() -> None:
+7 |     with power(12 + False):
   |                ^^^^^^^^^^ Binary operator `+` not defined for `int` and `bool`
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/power_arg_typecheck_inside.py b/tests/error/modifier_errors/power_arg_typecheck_inside.py
index 41e377908..1ba65855d 100644
--- a/tests/error/modifier_errors/power_arg_typecheck_inside.py
+++ b/tests/error/modifier_errors/power_arg_typecheck_inside.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import power
 
 
 @guppy
diff --git a/tests/error/modifier_errors/power_many_arg.err b/tests/error/modifier_errors/power_many_arg.err
index 0f4513e86..55622441d 100644
--- a/tests/error/modifier_errors/power_many_arg.err
+++ b/tests/error/modifier_errors/power_many_arg.err
@@ -1,8 +1,8 @@
-Error: Too many arguments (at $FILE:6:18)
+Error: Too many arguments (at $FILE:7:18)
   | 
-4 | @guppy
-5 | def test() -> None:
-6 |     with power(1, 2, 3):
+5 | @guppy
+6 | def test() -> None:
+7 |     with power(1, 2, 3):
   |                   ^^^^ Unexpected arguments (expected 1, got 3)
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/power_many_arg.py b/tests/error/modifier_errors/power_many_arg.py
index 0e9e953fe..115d616d0 100644
--- a/tests/error/modifier_errors/power_many_arg.py
+++ b/tests/error/modifier_errors/power_many_arg.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import power
 
 
 @guppy
diff --git a/tests/error/modifier_errors/power_no_arg.err b/tests/error/modifier_errors/power_no_arg.err
index 05c59a4b3..7ed84569e 100644
--- a/tests/error/modifier_errors/power_no_arg.err
+++ b/tests/error/modifier_errors/power_no_arg.err
@@ -1,8 +1,8 @@
-Error: Not enough arguments (at $FILE:6:14)
+Error: Not enough arguments (at $FILE:7:14)
   | 
-4 | @guppy
-5 | def test() -> None:
-6 |     with power():
+5 | @guppy
+6 | def test() -> None:
+7 |     with power():
   |               ^^ Missing argument (expected 1, got 0)
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/power_no_arg.py b/tests/error/modifier_errors/power_no_arg.py
index dbaafec9f..87c23895b 100644
--- a/tests/error/modifier_errors/power_no_arg.py
+++ b/tests/error/modifier_errors/power_no_arg.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import power
 
 
 @guppy
diff --git a/tests/error/modifier_errors/return_found.err b/tests/error/modifier_errors/return_found.err
index cfa3114be..daa017ce5 100644
--- a/tests/error/modifier_errors/return_found.err
+++ b/tests/error/modifier_errors/return_found.err
@@ -1,14 +1,14 @@
-Error: Unexpected return (at $FILE:7:8)
+Error: Unexpected return (at $FILE:8:8)
   | 
-5 | def test() -> None:
-6 |     with dagger:
-7 |         return
+6 | def test() -> None:
+7 |     with dagger:
+8 |         return
   |         ^^^^^^ Return found in a `With` block
 
 Note:
   | 
-5 | def test() -> None:
-6 |     with dagger:
+6 | def test() -> None:
+7 |     with dagger:
   |          ------ modifier is used here
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/return_found.py b/tests/error/modifier_errors/return_found.py
index 6ccc9eb3d..fdeffa727 100644
--- a/tests/error/modifier_errors/return_found.py
+++ b/tests/error/modifier_errors/return_found.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 
 
 @guppy
diff --git a/tests/error/modifier_errors/type_check_in_block.err b/tests/error/modifier_errors/type_check_in_block.err
index 23aa24027..a8fb7a94a 100644
--- a/tests/error/modifier_errors/type_check_in_block.err
+++ b/tests/error/modifier_errors/type_check_in_block.err
@@ -1,8 +1,8 @@
-Error: Operator not defined (at $FILE:7:8)
+Error: Operator not defined (at $FILE:8:8)
   | 
-5 | def test() -> None:
-6 |     with dagger:
-7 |         1 + True
+6 | def test() -> None:
+7 |     with dagger:
+8 |         1 + True
   |         ^^^^^^^^ Binary operator `+` not defined for `int` and `bool`
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/type_check_in_block.py b/tests/error/modifier_errors/type_check_in_block.py
index c25b862ed..ef9e9b0f4 100644
--- a/tests/error/modifier_errors/type_check_in_block.py
+++ b/tests/error/modifier_errors/type_check_in_block.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import dagger
 
 
 @guppy
diff --git a/tests/error/modifier_errors/variable_leak.err b/tests/error/modifier_errors/variable_leak.err
index 1be21c71b..d97893cd5 100644
--- a/tests/error/modifier_errors/variable_leak.err
+++ b/tests/error/modifier_errors/variable_leak.err
@@ -1,8 +1,8 @@
-Error: Variable not defined (at $FILE:9:11)
-  | 
-7 |     with power(1):
-8 |         x = 1
-9 |     return x + 2
-  |            ^ `x` is not defined
+Error: Variable not defined (at $FILE:10:11)
+   | 
+ 8 |     with power(1):
+ 9 |         x = 1
+10 |     return x + 2
+   |            ^ `x` is not defined
 
 Guppy compilation failed due to 1 previous error
diff --git a/tests/error/modifier_errors/variable_leak.py b/tests/error/modifier_errors/variable_leak.py
index 92827349f..87e1e170f 100644
--- a/tests/error/modifier_errors/variable_leak.py
+++ b/tests/error/modifier_errors/variable_leak.py
@@ -1,4 +1,5 @@
 from guppylang.decorator import guppy
+from guppylang.std.builtins import power
 
 
 # TODO: The error message is confusing.
diff --git a/tests/error/tracing_errors/control_in_comptime.err b/tests/error/tracing_errors/control_in_comptime.err
new file mode 100644
index 000000000..6e4db05c7
--- /dev/null
+++ b/tests/error/tracing_errors/control_in_comptime.err
@@ -0,0 +1,6 @@
+Traceback (most recent call last):
+  File "$FILE", line 16, in <module>
+    foo.compile()
+  File "$FILE", line 10, in foo
+    with control(q2):
+guppylang_internals.error.GuppyComptimeError: The `control` modifier is not supported in comptime functions
diff --git a/tests/error/tracing_errors/control_in_comptime.py b/tests/error/tracing_errors/control_in_comptime.py
new file mode 100644
index 000000000..9cbaa0cf3
--- /dev/null
+++ b/tests/error/tracing_errors/control_in_comptime.py
@@ -0,0 +1,16 @@
+from guppylang import guppy
+from guppylang.std.quantum import qubit, h, measure
+from guppylang.std.lang import control
+
+
+@guppy.comptime
+def foo() -> None:
+    q1 = qubit()
+    q2 = qubit()
+    with control(q2):
+        h(q1)
+    measure(q1)
+    measure(q2) 
+
+
+foo.compile()
diff --git a/tests/error/tracing_errors/dagger_in_comptime.err b/tests/error/tracing_errors/dagger_in_comptime.err
new file mode 100644
index 000000000..4d23e6a65
--- /dev/null
+++ b/tests/error/tracing_errors/dagger_in_comptime.err
@@ -0,0 +1,6 @@
+Traceback (most recent call last):
+  File "$FILE", line 14, in <module>
+    foo.compile()
+  File "$FILE", line 9, in foo
+    with dagger():
+guppylang_internals.error.GuppyComptimeError: The `dagger` modifier is not supported in comptime functions
diff --git a/tests/error/tracing_errors/dagger_in_comptime.py b/tests/error/tracing_errors/dagger_in_comptime.py
new file mode 100644
index 000000000..9bfa99cf9
--- /dev/null
+++ b/tests/error/tracing_errors/dagger_in_comptime.py
@@ -0,0 +1,14 @@
+from guppylang import guppy
+from guppylang.std.quantum import qubit, h, measure
+from guppylang.std.lang import dagger
+
+
+@guppy.comptime
+def foo() -> None:
+    q1 = qubit()
+    with dagger():
+        h(q1)
+    measure(q1)
+    
+
+foo.compile()
diff --git a/tests/error/tracing_errors/power_in_comptime.err b/tests/error/tracing_errors/power_in_comptime.err
new file mode 100644
index 000000000..424f21c88
--- /dev/null
+++ b/tests/error/tracing_errors/power_in_comptime.err
@@ -0,0 +1,6 @@
+Traceback (most recent call last):
+  File "$FILE", line 14, in <module>
+    foo.compile()
+  File "$FILE", line 9, in foo
+    with power(2):
+guppylang_internals.error.GuppyComptimeError: The `power` modifier is not supported in comptime functions
diff --git a/tests/error/tracing_errors/power_in_comptime.py b/tests/error/tracing_errors/power_in_comptime.py
new file mode 100644
index 000000000..e28c8bdec
--- /dev/null
+++ b/tests/error/tracing_errors/power_in_comptime.py
@@ -0,0 +1,14 @@
+from guppylang import guppy
+from guppylang.std.quantum import qubit, h, measure 
+from guppylang.std.lang import power
+
+
+@guppy.comptime
+def foo() -> None:
+    q1 = qubit()
+    with power(2):
+        h(q1)
+    measure(q1)
+    
+
+foo.compile()
diff --git a/tests/integration/test_modifier.py b/tests/integration/test_modifier.py
index c1209c9f1..16b07d453 100644
--- a/tests/integration/test_modifier.py
+++ b/tests/integration/test_modifier.py
@@ -1,15 +1,9 @@
 from guppylang.decorator import guppy
 from guppylang.std.quantum import qubit
 from guppylang.std.num import nat
-from guppylang.std.builtins import owned
+from guppylang.std.builtins import owned, control, dagger, power
 from guppylang.std.array import array
 
-# Dummy variables to suppress Undefined name
-# TODO: `ruff` fails when without these, which need to be fixed
-dagger = object()
-control = object()
-power = object()
-
 
 def test_dagger_simple(validate):
     @guppy