From 5831b68341827b544ea3f268c921e9044bd11047 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Thu, 8 Dec 2022 19:28:01 +0200
Subject: [PATCH] AstGen: add check for missing builtin argument

Closes #13817
---
 src/AstGen.zig                                      |  4 ++++
 .../missing_builtin_arg_in_initializer.zig          | 13 +++++++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 test/cases/compile_errors/missing_builtin_arg_in_initializer.zig

diff --git a/src/AstGen.zig b/src/AstGen.zig
index c9f44a6216..021990883a 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -9098,6 +9098,8 @@ fn nodeMayNeedMemoryLocation(tree: *const Ast, start_node: Ast.Node.Index, have_
                     .always => return true,
                     .forward1 => node = node_datas[node].rhs,
                 }
+                // Missing builtin arg is not a parsing error, expect an error later.
+                if (node == 0) return false;
             },
 
             .builtin_call, .builtin_call_comma => {
@@ -9112,6 +9114,8 @@ fn nodeMayNeedMemoryLocation(tree: *const Ast, start_node: Ast.Node.Index, have_
                     .always => return true,
                     .forward1 => node = params[1],
                 }
+                // Missing builtin arg is not a parsing error, expect an error later.
+                if (node == 0) return false;
             },
         }
     }
diff --git a/test/cases/compile_errors/missing_builtin_arg_in_initializer.zig b/test/cases/compile_errors/missing_builtin_arg_in_initializer.zig
new file mode 100644
index 0000000000..0bada117b2
--- /dev/null
+++ b/test/cases/compile_errors/missing_builtin_arg_in_initializer.zig
@@ -0,0 +1,13 @@
+comptime {
+    const v = @as();
+}
+comptime {
+    const u = @bitCast(u32);
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :2:15: error: expected 2 arguments, found 0
+// :5:15: error: expected 2 arguments, found 1