diff --git a/example_Into_test.go b/example_Into_test.go
index e70ed60..08d36ac 100644
--- a/example_Into_test.go
+++ b/example_Into_test.go
@@ -1,3 +1,5 @@
+//go:build go1.18
+
 package errors_test
 
 import (
diff --git a/example_Must_test.go b/example_Must_test.go
index 286c238..32f3a8a 100644
--- a/example_Must_test.go
+++ b/example_Must_test.go
@@ -1,3 +1,5 @@
+//go:build go1.18
+
 package errors_test
 
 import (
diff --git a/into.go b/into.go
index 7a867d6..01ef7cf 100644
--- a/into.go
+++ b/into.go
@@ -1,3 +1,5 @@
+//go:build go1.18
+
 package errors
 
 // Into finds the first error in err's chain that matches target type T, and if so, returns it.
diff --git a/must.go b/must.go
index e9c83c3..ff06f8c 100644
--- a/must.go
+++ b/must.go
@@ -1,3 +1,5 @@
+//go:build go1.18
+
 package errors
 
 // Must is a generic helper, like template.Must, that wraps a call to a function returning (T, error)
diff --git a/must_test.go b/must_test.go
index b3a579b..9cc948f 100644
--- a/must_test.go
+++ b/must_test.go
@@ -1,3 +1,5 @@
+//go:build go1.18
+
 package errors
 
 import (