Add test of eager expansion failure in a stability attribute

Author: dtolnay

tests/ui/stability-attribute/eager-expansion-fail.rs

@@ -0,0 +1,27 @@
+#![crate_type = "lib"]
+#![feature(staged_api)]
+#![stable(feature = "stable_test_feature", since = "3.3.3")]
+
+macro_rules! not_a_literal {
+    () => {
+        boohoo
+    };
+}
+
+macro_rules! m {
+    () => {
+        #[stable(feature = 1 + 1, since = "?")]
+        //~^ expression in the value of this attribute must be a literal or macro call
+        //~^^ incorrect meta item
+        //~^^^ incorrect meta item
+        pub struct Math; //~ struct has missing stability attribute
+
+        #[stable(feature = not_a_literal!(), since = "?")]
+        //~^ expression in the value of this attribute must be a literal or macro call
+        //~^^ incorrect meta item
+        //~^^^ incorrect meta item
+        pub struct NotLiteral; //~ struct has missing stability attribute
+    };
+}
+
+m!();

tests/ui/stability-attribute/eager-expansion-fail.stderr

@@ -0,0 +1,93 @@
+error: expression in the value of this attribute must be a literal or macro call
+  --> $DIR/eager-expansion-fail.rs:13:28
+   |
+LL |         #[stable(feature = 1 + 1, since = "?")]
+   |                            ^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: expression in the value of this attribute must be a literal or macro call
+  --> $DIR/eager-expansion-fail.rs:19:28
+   |
+LL |         #[stable(feature = not_a_literal!(), since = "?")]
+   |                            ^^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0539]: incorrect meta item
+  --> $DIR/eager-expansion-fail.rs:13:18
+   |
+LL |         #[stable(feature = 1 + 1, since = "?")]
+   |                  ^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0539]: incorrect meta item
+  --> $DIR/eager-expansion-fail.rs:13:18
+   |
+LL |         #[stable(feature = 1 + 1, since = "?")]
+   |                  ^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0539]: incorrect meta item
+  --> $DIR/eager-expansion-fail.rs:19:18
+   |
+LL |         #[stable(feature = not_a_literal!(), since = "?")]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0539]: incorrect meta item
+  --> $DIR/eager-expansion-fail.rs:19:18
+   |
+LL |         #[stable(feature = not_a_literal!(), since = "?")]
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: struct has missing stability attribute
+  --> $DIR/eager-expansion-fail.rs:17:9
+   |
+LL |         pub struct Math;
+   |         ^^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: struct has missing stability attribute
+  --> $DIR/eager-expansion-fail.rs:23:9
+   |
+LL |         pub struct NotLiteral;
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+...
+LL | m!();
+   | ---- in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0539`.