resolve/expand: Improve attribute expansion on macro definitions and calls

src/test/ui/attributes/key-value-expansion-on-mac.rs

@@ -0,0 +1,15 @@
+#![feature(extended_key_value_attributes)]
+#![feature(rustc_attrs)]
+
+#[rustc_dummy = stringify!(a)] // OK
+macro_rules! bar {
+    () => {};
+}
+
+// FIXME?: `bar` here expands before `stringify` has a chance to expand.
+// `#[rustc_dummy = ...]` is validated and dropped during expansion of `bar`,
+// the "unexpected token" errors comes from the validation.
+#[rustc_dummy = stringify!(b)] //~ ERROR unexpected token: `stringify!(b)`
+bar!();
+
+fn main() {}

src/test/ui/attributes/key-value-expansion-on-mac.stderr

@@ -0,0 +1,8 @@
+error: unexpected token: `stringify!(b)`
+  --> $DIR/key-value-expansion-on-mac.rs:12:17
+   |
+LL | #[rustc_dummy = stringify!(b)]
+   |                 ^^^^^^^^^^^^^
+
+error: aborting due to previous error
+

src/test/ui/feature-gates/issue-43106-gating-of-builtin-attrs.stderr

@@ -172,12 +172,6 @@ warning: unknown lint: `x5100`
 LL |     #[deny(x5100)] impl S { }
    |            ^^^^^
 
-warning: `#[macro_escape]` is a deprecated synonym for `#[macro_use]`
-  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:438:1
-   |
-LL | #[macro_escape]
-   | ^^^^^^^^^^^^^^^
-
 warning: `#[macro_escape]` is a deprecated synonym for `#[macro_use]`
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:441:17
    |
@@ -186,6 +180,12 @@ LL |     mod inner { #![macro_escape] }
    |
    = help: try an outer attribute: `#[macro_use]`
 
+warning: `#[macro_escape]` is a deprecated synonym for `#[macro_use]`
+  --> $DIR/issue-43106-gating-of-builtin-attrs.rs:438:1
+   |
+LL | #[macro_escape]
+   | ^^^^^^^^^^^^^^^
+
 warning: use of deprecated attribute `plugin_registrar`: compiler plugins are deprecated. See https://github.com/rust-lang/rust/pull/64675
   --> $DIR/issue-43106-gating-of-builtin-attrs.rs:228:17
    |

src/test/ui/feature-gates/issue-43106-gating-of-macro_use.stderr

@@ -1,8 +1,8 @@
 error: arguments to `macro_use` are not allowed here
-  --> $DIR/issue-43106-gating-of-macro_use.rs:6:1
+  --> $DIR/issue-43106-gating-of-macro_use.rs:12:17
    |
-LL | #![macro_use(my_macro)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^
+LL |     mod inner { #![macro_use(my_macro)] }
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: arguments to `macro_use` are not allowed here
   --> $DIR/issue-43106-gating-of-macro_use.rs:9:1
@@ -11,10 +11,10 @@ LL | #[macro_use(my_macro)]
    | ^^^^^^^^^^^^^^^^^^^^^^
 
 error: arguments to `macro_use` are not allowed here
-  --> $DIR/issue-43106-gating-of-macro_use.rs:12:17
+  --> $DIR/issue-43106-gating-of-macro_use.rs:6:1
    |
-LL |     mod inner { #![macro_use(my_macro)] }
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^
+LL | #![macro_use(my_macro)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: malformed `macro_use` attribute input
   --> $DIR/issue-43106-gating-of-macro_use.rs:15:5