Bypass 'invalid meta item' error when an error already shown

Author: dtolnay

compiler/rustc_attr/src/builtin.rs

@@ -330,7 +330,9 @@ fn insert_or_error(sess: &Session, meta: &MetaItem, item: &mut Option<Symbol>) -
         *item = Some(v);
         Some(())
     } else {
-        sess.emit_err(session_diagnostics::IncorrectMetaItem { span: meta.span });
+        if !matches!(meta.kind, MetaItemKind::NameValue(MetaItemLit { kind: LitKind::Err, .. })) {
+            sess.emit_err(session_diagnostics::IncorrectMetaItem { span: meta.span });
+        }
         None
     }
 }

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

@@ -10,16 +10,10 @@ macro_rules! not_a_literal {
 
 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
+        #[stable(feature = 1 + 1, since = "?")] //~ expression in the value of this attribute must be a literal or macro call
         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
+        #[stable(feature = not_a_literal!(), since = "?")] //~ expression in the value of this attribute must be a literal or macro call
         pub struct NotLiteral; //~ struct has missing stability attribute
     };
 }

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

@@ -10,7 +10,7 @@ LL | m!();
    = 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
+  --> $DIR/eager-expansion-fail.rs:16:28
    |
 LL |         #[stable(feature = not_a_literal!(), since = "?")]
    |                            ^^^^^^^^^^^^^^^^
@@ -20,54 +20,8 @@ LL | m!();
    |
    = 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
+  --> $DIR/eager-expansion-fail.rs:14:9
    |
 LL |         pub struct Math;
    |         ^^^^^^^^^^^^^^^^
@@ -78,7 +32,7 @@ LL | m!();
    = 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
+  --> $DIR/eager-expansion-fail.rs:17:9
    |
 LL |         pub struct NotLiteral;
    |         ^^^^^^^^^^^^^^^^^^^^^^
@@ -88,6 +42,5 @@ LL | m!();
    |
    = 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
+error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0539`.