zig

commit f77c968cf841046238eb37f54600cda201f09ce2 (tree)
parent eeae3a8f9df49e53392bcd7b04b463f6bffcec9c
Author: Ryan Liptak <squeek502@hotmail.com>
Date:   Wed,  8 Jul 2020 00:53:19 -0700

langref: Add test case for "if error union with optional"

This is an edge case that isn't too uncommon but is rather confusing to try to deduce without documentation, since it feels like `else` is being overloaded in this scenario and there's no obvious 'correct' behavior here. This just adds a test demonstrating how Zig currently behaves in this scenario.

Diffstat:
M
doc/langref.html.in
 | 
26
++++++++++++++++++++++++++

1 file changed, 26 insertions(+), 0 deletions(-)
diff --git a/doc/langref.html.in b/doc/langref.html.in
@@ -3861,6 +3861,32 @@ test "if error union" {
         unreachable;
     }
 }
+
+test "if error union with optional" {
+    // If expressions test for errors before unwrapping optionals.
+    // The |optional_value| capture's type is ?u32.
+
+    const a: anyerror!?u32 = 0;
+    if (a) |optional_value| {
+        assert(optional_value.? == 0);
+    } else |err| {
+        unreachable;
+    }
+
+    const b: anyerror!?u32 = null;
+    if (b) |optional_value| {
+        assert(optional_value == null);
+    } else |err| {
+        unreachable;
+    }
+
+    const c: anyerror!?u32 = error.BadValue;
+    if (c) |optional_value| {
+        unreachable;
+    } else |err| {
+        assert(err == error.BadValue);
+    }
+}
       {#code_end#}
       {#see_also|Optionals|Errors#}
       {#header_close#}