Tweak diagnostics

- Tweak lint message
- Display multi-segment paths correctly

compiler/rustc_passes/src/check_attr.rs

@@ -597,11 +597,14 @@ impl CheckAttrVisitor<'tcx> {
                                 hir_id,
                                 i_meta.span,
                                 |lint| {
-                                    lint.build(&format!(
-                                        "unknown `doc` attribute `{}`",
-                                        i_meta.name_or_empty()
-                                    ))
-                                    .emit();
+                                    let msg = if let Ok(snippet) =
+                                        self.tcx.sess.source_map().span_to_snippet(i_meta.path.span)
+                                    {
+                                        format!("unknown `doc` attribute `{}`", snippet,)
+                                    } else {
+                                        String::from("unknown `doc` attribute")
+                                    };
+                                    lint.build(&msg).emit();
                                 },
                             );
                             is_valid = false;
@@ -613,7 +616,7 @@ impl CheckAttrVisitor<'tcx> {
                         hir_id,
                         meta.span(),
                         |lint| {
-                            lint.build(&format!("unknown `doc` attribute")).emit();
+                            lint.build(&format!("invalid `doc` attribute")).emit();
                         },
                     );
                     is_valid = false;

src/test/rustdoc-ui/doc-attr.rs

@@ -10,12 +10,12 @@
 pub fn foo() {}
 
 #[doc(123)]
-//~^ ERROR unknown `doc` attribute
+//~^ ERROR invalid `doc` attribute
 //~| WARN
 #[doc("hello", "bar")]
-//~^ ERROR unknown `doc` attribute
+//~^ ERROR invalid `doc` attribute
 //~| WARN
-//~| ERROR unknown `doc` attribute
+//~| ERROR invalid `doc` attribute
 //~| WARN
 #[doc(foo::bar, crate::bar::baz = "bye")]
 //~^ ERROR unknown `doc` attribute

src/test/rustdoc-ui/doc-attr.stderr

@@ -13,7 +13,7 @@ LL | #![deny(warnings)]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute
+error: invalid `doc` attribute
   --> $DIR/doc-attr.rs:12:7
    |
 LL | #[doc(123)]
@@ -22,7 +22,7 @@ LL | #[doc(123)]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute
+error: invalid `doc` attribute
   --> $DIR/doc-attr.rs:15:7
    |
 LL | #[doc("hello", "bar")]
@@ -31,7 +31,7 @@ LL | #[doc("hello", "bar")]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute
+error: invalid `doc` attribute
   --> $DIR/doc-attr.rs:15:16
    |
 LL | #[doc("hello", "bar")]
@@ -40,7 +40,7 @@ LL | #[doc("hello", "bar")]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute ``
+error: unknown `doc` attribute `foo::bar`
   --> $DIR/doc-attr.rs:20:7
    |
 LL | #[doc(foo::bar, crate::bar::baz = "bye")]
@@ -49,7 +49,7 @@ LL | #[doc(foo::bar, crate::bar::baz = "bye")]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute ``
+error: unknown `doc` attribute `crate::bar::baz`
   --> $DIR/doc-attr.rs:20:17
    |
 LL | #[doc(foo::bar, crate::bar::baz = "bye")]

src/test/ui/attributes/doc-attr.rs

@@ -10,12 +10,12 @@
 pub fn foo() {}
 
 #[doc(123)]
-//~^ ERROR unknown `doc` attribute
+//~^ ERROR invalid `doc` attribute
 //~| WARN
 #[doc("hello", "bar")]
-//~^ ERROR unknown `doc` attribute
+//~^ ERROR invalid `doc` attribute
 //~| WARN
-//~| ERROR unknown `doc` attribute
+//~| ERROR invalid `doc` attribute
 //~| WARN
 #[doc(foo::bar, crate::bar::baz = "bye")]
 //~^ ERROR unknown `doc` attribute

src/test/ui/attributes/doc-attr.stderr

@@ -13,7 +13,7 @@ LL | #![deny(warnings)]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute
+error: invalid `doc` attribute
   --> $DIR/doc-attr.rs:12:7
    |
 LL | #[doc(123)]
@@ -22,7 +22,7 @@ LL | #[doc(123)]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute
+error: invalid `doc` attribute
   --> $DIR/doc-attr.rs:15:7
    |
 LL | #[doc("hello", "bar")]
@@ -31,7 +31,7 @@ LL | #[doc("hello", "bar")]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute
+error: invalid `doc` attribute
   --> $DIR/doc-attr.rs:15:16
    |
 LL | #[doc("hello", "bar")]
@@ -40,7 +40,7 @@ LL | #[doc("hello", "bar")]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute ``
+error: unknown `doc` attribute `foo::bar`
   --> $DIR/doc-attr.rs:20:7
    |
 LL | #[doc(foo::bar, crate::bar::baz = "bye")]
@@ -49,7 +49,7 @@ LL | #[doc(foo::bar, crate::bar::baz = "bye")]
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
 
-error: unknown `doc` attribute ``
+error: unknown `doc` attribute `crate::bar::baz`
   --> $DIR/doc-attr.rs:20:17
    |
 LL | #[doc(foo::bar, crate::bar::baz = "bye")]