typing out the stuff on the website

overflow.zig

@@ -0,0 +1,4 @@
+test "integer overflow at compile time" {
+    const x: u8 = 255;
+    const y = x + 1;
+}

runtime_overflow.zig

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+test "integer overflow at runtime" {
+    var x: u8 = 255;
+    x += 1;
+}

undefined.zig

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+const std = @import("std");
+
+pub fn main() void {
+    // if you remove this line, the program does not compile because it detects
+    // the overflow at compile time. A little confusing that it's not
+    // @setCompileTimeSafety but that's ok.
+    @setRuntimeSafety(false);
+
+    var x: u8 = 255;
+    x += 1; // <-- this is an overflow
+
+    // this prints 0 on my machine but is apparently undefined. I wonder what
+    // it prints on other machines?
+    std.debug.print("X: {}\n", .{x});
+}