diff --git a/test/incremental/add_decl b/test/incremental/add_decl
new file mode 100644
index 0000000000..b842593056
--- /dev/null
+++ b/test/incremental/add_decl
@@ -0,0 +1,62 @@
+#target=x86_64-linux-selfhosted
+#target=x86_64-linux-cbe
+#target=x86_64-windows-cbe
+//#target=wasm32-wasi-selfhosted
+#update=initial version
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(foo);
+}
+const foo = "good morning\n";
+#expect_stdout="good morning\n"
+
+#update=add new declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(foo);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+#expect_stdout="good morning\n"
+
+#update=reference new declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(bar);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+#expect_stdout="good evening\n"
+
+#update=reference missing declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(qux);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+#expect_error=ignored
+
+#update=add missing declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(qux);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+const qux = "good night\n";
+#expect_stdout="good night\n"
+
+#update=remove unused declarations
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(qux);
+}
+const qux = "good night\n";
+#expect_stdout="good night\n"
diff --git a/test/incremental/add_decl_namespaced b/test/incremental/add_decl_namespaced
new file mode 100644
index 0000000000..a42e5600bc
--- /dev/null
+++ b/test/incremental/add_decl_namespaced
@@ -0,0 +1,62 @@
+#target=x86_64-linux-selfhosted
+#target=x86_64-linux-cbe
+#target=x86_64-windows-cbe
+//#target=wasm32-wasi-selfhosted
+#update=initial version
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(@This().foo);
+}
+const foo = "good morning\n";
+#expect_stdout="good morning\n"
+
+#update=add new declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(@This().foo);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+#expect_stdout="good morning\n"
+
+#update=reference new declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(@This().bar);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+#expect_stdout="good evening\n"
+
+#update=reference missing declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(@This().qux);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+#expect_error=ignored
+
+#update=add missing declaration
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(@This().qux);
+}
+const foo = "good morning\n";
+const bar = "good evening\n";
+const qux = "good night\n";
+#expect_stdout="good night\n"
+
+#update=remove unused declarations
+#file=main.zig
+const std = @import("std");
+pub fn main() !void {
+    try std.io.getStdOut().writeAll(@This().qux);
+}
+const qux = "good night\n";
+#expect_stdout="good night\n"