diff --git a/tests/functional/lang/eval-fail-fromTOML-overflow.err.exp b/tests/functional/lang/eval-fail-fromTOML-overflow.err.exp
new file mode 100644
index 000000000..14b0e31c1
--- /dev/null
+++ b/tests/functional/lang/eval-fail-fromTOML-overflow.err.exp
@@ -0,0 +1,13 @@
+error:
+       … while calling the 'fromTOML' builtin
+         at /pwd/lang/eval-fail-fromTOML-overflow.nix:1:1:
+            1| builtins.fromTOML ''attr = 9223372036854775808''
+             | ^
+            2|
+
+       error: while parsing TOML: [error] toml::parse_dec_integer: too large integer: current max digits = 2^63
+        --> fromTOML
+          |
+        1 | attr = 9223372036854775808
+          |                           ^-- must be < 2^63
+       
diff --git a/tests/functional/lang/eval-fail-fromTOML-overflow.nix b/tests/functional/lang/eval-fail-fromTOML-overflow.nix
new file mode 100644
index 000000000..17f0448b3
--- /dev/null
+++ b/tests/functional/lang/eval-fail-fromTOML-overflow.nix
@@ -0,0 +1 @@
+builtins.fromTOML ''attr = 9223372036854775808''
diff --git a/tests/functional/lang/eval-fail-fromTOML-underflow.err.exp b/tests/functional/lang/eval-fail-fromTOML-underflow.err.exp
new file mode 100644
index 000000000..28f1079dc
--- /dev/null
+++ b/tests/functional/lang/eval-fail-fromTOML-underflow.err.exp
@@ -0,0 +1,13 @@
+error:
+       … while calling the 'fromTOML' builtin
+         at /pwd/lang/eval-fail-fromTOML-underflow.nix:1:1:
+            1| builtins.fromTOML ''attr = -9223372036854775809''
+             | ^
+            2|
+
+       error: while parsing TOML: [error] toml::parse_dec_integer: too large integer: current max digits = 2^63
+        --> fromTOML
+          |
+        1 | attr = -9223372036854775809
+          |                            ^-- must be < 2^63
+       
diff --git a/tests/functional/lang/eval-fail-fromTOML-underflow.nix b/tests/functional/lang/eval-fail-fromTOML-underflow.nix
new file mode 100644
index 000000000..923fdf354
--- /dev/null
+++ b/tests/functional/lang/eval-fail-fromTOML-underflow.nix
@@ -0,0 +1 @@
+builtins.fromTOML ''attr = -9223372036854775809''