fix comptime pointer reinterpretation array index offset

closes #1835

1 files changed, 17 insertions, 0 deletions

diff --git a/test/cases/ptrcast.zig b/test/cases/ptrcast.zig
new file mode 100644
index 0000000000..071087c5c4
--- /dev/null
+++ b/test/cases/ptrcast.zig
@@ -0,0 +1,17 @@
+const builtin = @import("builtin");
+const std = @import("std");
+const assertOrPanic = std.debug.assertOrPanic;
+
+test "reinterpret bytes as integer with nonzero offset" {
+    testReinterpretBytesAsInteger();
+    comptime testReinterpretBytesAsInteger();
+}
+
+fn testReinterpretBytesAsInteger() void {
+    const bytes = "\x12\x34\x56\x78\xab";
+    const expected = switch (builtin.endian) {
+        builtin.Endian.Little => 0xab785634,
+        builtin.Endian.Big => 0x345678ab,
+    };
+    assertOrPanic(@ptrCast(*align(1) const u32, bytes[1..5].ptr).* == expected);
+}