handle macro_rules substitutions across the codebase

testlib/src/lib.rs

@@ -228,6 +228,24 @@ pub fn rejected(
     }
 }
 
+// Fixture for TokenStreamWrapper values.
+#[derive(Deserialize)]
+#[allow(dead_code)]
+struct Tokens {
+    tokens: serde_tokenstream::TokenStreamWrapper,
+}
+
+#[proc_macro_attribute]
+pub fn tokens(
+    attr: proc_macro::TokenStream,
+    item: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+    match from_tokenstream::<Tokens>(&attr.into()) {
+        Ok(_) => item,
+        Err(err) => err.to_compile_error().into(),
+    }
+}
+
 #[proc_macro_attribute]
 pub fn outer(
     _attr: proc_macro::TokenStream,

ui-tests/tests/ui/bad_parse_wrapper_from_macro_rules_empty.rs

@@ -0,0 +1,23 @@
+// Copyright 2026 Oxide Computer Company
+
+// An empty macro_rules substitution into a ParseWrapper must produce a
+// missing-value error, similar to plain values.
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($v:vis ,) => {
+        #[annotation {
+            string = "test",
+            options = OptionA,
+            unit = (),
+            tup = (1, 2.0),
+            bool_expr = $v,
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(,);
+
+fn main() {}

ui-tests/tests/ui/bad_parse_wrapper_from_macro_rules_empty.stderr

@@ -0,0 +1,10 @@
+error: expected a value, but found `,`
+  --> tests/ui/bad_parse_wrapper_from_macro_rules_empty.rs:15:27
+   |
+15 |             bool_expr = $v,
+   |                           ^
+...
+21 | wrap!(,);
+   | -------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/bad_string_from_macro_rules_empty.rs

@@ -0,0 +1,22 @@
+// Copyright 2026 Oxide Computer Company
+
+// An empty macro_rules substitution (such as an empty `vis`) must be a
+// missing-value error, not a panic.
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($v:vis ,) => {
+        #[annotation {
+            string = $v,
+            options = OptionA,
+            unit = (),
+            tup = (1, 2.0),
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(,);
+
+fn main() {}

ui-tests/tests/ui/bad_string_from_macro_rules_empty.stderr

@@ -0,0 +1,10 @@
+error: expected a string, but found `,`
+  --> tests/ui/bad_string_from_macro_rules_empty.rs:11:24
+   |
+11 |             string = $v,
+   |                        ^
+...
+20 | wrap!(,);
+   | -------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/bad_string_from_macro_rules_path.stderr

@@ -1,4 +1,4 @@
-error: expected a string, but found `foo::bar`
+error: expected only a string, but found `foo::bar`
   --> tests/ui/bad_string_from_macro_rules_path.rs:20:7
    |
 20 | wrap!(foo::bar);

ui-tests/tests/ui/bad_token_stream_wrapper_from_macro_rules_empty.rs

@@ -0,0 +1,19 @@
+// Copyright 2026 Oxide Computer Company
+
+// An empty macro_rules substitution into a TokenStreamWrapper must produce a
+// missing-value error.
+
+use testlib::tokens;
+
+macro_rules! wrap {
+    ($v:vis ,) => {
+        #[tokens {
+            tokens = $v,
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(,);
+
+fn main() {}

ui-tests/tests/ui/bad_token_stream_wrapper_from_macro_rules_empty.stderr

@@ -0,0 +1,10 @@
+error: expected a value, but found `,`
+  --> tests/ui/bad_token_stream_wrapper_from_macro_rules_empty.rs:11:24
+   |
+11 |             tokens = $v,
+   |                        ^
+...
+17 | wrap!(,);
+   | -------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/parse_wrapper_from_macro_rules_empty.rs

@@ -0,0 +1,24 @@
+// Copyright 2026 Oxide Computer Company
+
+// Empty macro_rules substitutions around a ParseWrapper value must be skipped.
+// (The error produced must be for the later `maybe_string` field.)
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($v:vis ,) => {
+        #[annotation {
+            string = "test",
+            options = OptionA,
+            unit = (),
+            tup = (1, 2.0),
+            bool_expr = $v true $v,
+            maybe_string = 1,
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(,);
+
+fn main() {}

ui-tests/tests/ui/parse_wrapper_from_macro_rules_empty.stderr

@@ -0,0 +1,10 @@
+error: expected a string, but found `1`
+  --> tests/ui/parse_wrapper_from_macro_rules_empty.rs:16:28
+   |
+16 |             maybe_string = 1,
+   |                            ^
+...
+22 | wrap!(,);
+   | -------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/string_from_macro_rules.rs

@@ -0,0 +1,23 @@
+// Copyright 2026 Oxide Computer Company
+
+// With macro_rules substitutions, rustc will wrap the substitutions inside a
+// `Delimiter::None` group. Ensure that such groups are accepted. (In this
+// test, the error produced must be for the later `unit` field.)
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($s:expr) => {
+        #[annotation {
+            string = $s,
+            options = OptionA,
+            unit = 1,
+            tup = (1, 2.0),
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(foo);
+
+fn main() {}

ui-tests/tests/ui/string_from_macro_rules.stderr

@@ -0,0 +1,10 @@
+error: expected a unit, but found `1`
+  --> tests/ui/string_from_macro_rules.rs:14:20
+   |
+14 |             unit = 1,
+   |                    ^
+...
+21 | wrap!(foo);
+   | ---------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/string_from_macro_rules_empty_prefix.rs

@@ -0,0 +1,23 @@
+// Copyright 2026 Oxide Computer Company
+
+// An empty macro_rules substitution before a value must be skipped. (The error
+// produced must be for the later `maybe_string` field.)
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($v:vis ,) => {
+        #[annotation {
+            string = $v foo,
+            options = OptionA,
+            unit = (),
+            tup = (1, 2.0),
+            maybe_string = 1,
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(,);
+
+fn main() {}

ui-tests/tests/ui/string_from_macro_rules_empty_prefix.stderr

@@ -0,0 +1,10 @@
+error: expected a string, but found `1`
+  --> tests/ui/string_from_macro_rules_empty_prefix.rs:15:28
+   |
+15 |             maybe_string = 1,
+   |                            ^
+...
+21 | wrap!(,);
+   | -------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/string_from_macro_rules_empty_suffix.rs

@@ -0,0 +1,23 @@
+// Copyright 2026 Oxide Computer Company
+
+// An macro_rules substitution after a value must be skipped. (The error
+// produced must be for the later `maybe_string` field.)
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($v:vis ,) => {
+        #[annotation {
+            string = foo $v,
+            options = OptionA,
+            unit = (),
+            tup = (1, 2.0),
+            maybe_string = 1,
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(,);
+
+fn main() {}

ui-tests/tests/ui/string_from_macro_rules_empty_suffix.stderr

@@ -0,0 +1,10 @@
+error: expected a string, but found `1`
+  --> tests/ui/string_from_macro_rules_empty_suffix.rs:15:28
+   |
+15 |             maybe_string = 1,
+   |                            ^
+...
+21 | wrap!(,);
+   | -------- in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)

ui-tests/tests/ui/values_from_macro_rules.rs

@@ -0,0 +1,26 @@
+// Copyright 2026 Oxide Computer Company
+
+// Test that macro_rules substitutions are accepted for every value kind. (The
+// error must be for the later `maybe_string` field.)
+
+use testlib::annotation;
+
+macro_rules! wrap {
+    ($o:expr, $u:expr, $t:expr, $m:expr, $n:expr, $g:expr) => {
+        #[annotation {
+            string = "test",
+            options = $o,
+            unit = $u,
+            tup = $t,
+            many = $m,
+            nested = { squeaker = "x", eyas = $n, gosling = 1.0 },
+            painted = { color = { red = true, green = $g, blue = false } },
+            maybe_string = 1,
+        }]
+        fn test() {}
+    };
+}
+
+wrap!(OptionA, (), (1, 2.0), ["a", b], 7, false);
+
+fn main() {}

ui-tests/tests/ui/values_from_macro_rules.stderr

@@ -0,0 +1,10 @@
+error: expected a string, but found `1`
+  --> tests/ui/values_from_macro_rules.rs:18:28
+   |
+18 |             maybe_string = 1,
+   |                            ^
+...
+24 | wrap!(OptionA, (), (1, 2.0), ["a", b], 7, false);
+   | ------------------------------------------------ in this macro invocation
+   |
+   = note: this error originates in the macro `wrap` (in Nightly builds, run with -Z macro-backtrace for more info)