diff --git a/lib/std/debug.zig b/lib/std/debug.zig
index 8aaee0e29edaba4523a70710de7eca31cf0bc078..898ae314d9084e35fed670b03854959ec06beead 100644
--- a/lib/std/debug.zig
+++ b/lib/std/debug.zig
@@ -237,13 +237,12 @@ pub const Symbol = struct {
     };
 };
 
-/// Deprecated because it returns the optimization mode of the standard
-/// library, when the caller probably wants to use the optimization mode of
-/// their own module.
-pub const runtime_safety = switch (builtin.mode) {
-    .debug, .safe => true,
-    .fast, .small => false,
-};
+/// Deprecated in favor of `std.lang.Optimize.runtimeSafety`, to be removed after 0.18.0
+///
+/// Returns whether the standard library has safety checks enabled. Callsites
+/// likely would rather know whether their own module's optimization mode
+/// (found via `@import("builtin").optimize`) has safety checks enabled.
+pub const runtime_safety = builtin.mode.runtimeSafety();
 
 /// Whether we can unwind the stack on this target, allowing capturing and/or printing the current
 /// stack trace. It is still legal to call `captureCurrentStackTrace`, `writeCurrentStackTrace`, and
diff --git a/lib/std/lang.zig b/lib/std/lang.zig
index daa2482eec7429bcd90a83ae2e2515681be29187..2f0868c39331456b03f055cafd8546f19ac51b07 100644
--- a/lib/std/lang.zig
+++ b/lib/std/lang.zig
@@ -144,6 +144,15 @@ pub const Optimize = enum {
             .{ "small", .small },
         }).get(s);
     }
+
+    /// Returns whether illegal behavior safety checks are enabled based on the
+    /// provided optimization mode.
+    pub fn runtimeSafety(o: @This()) bool {
+        return switch (o) {
+            .debug, .safe => true,
+            .fast, .small => false,
+        };
+    }
 };
 
 /// The calling convention of a function defines how arguments and return values are passed, as well