From 7189c05bf8fe5b9d21815c44540d76301c90a8aa Mon Sep 17 00:00:00 2001
From: Camelid <camelidcamel@gmail.com>
Date: Sat, 13 Mar 2021 13:25:27 -0800
Subject: [PATCH] Lint non-meta doc attributes

E.g., `#[doc(123)]`.
---
 compiler/rustc_passes/src/check_attr.rs | 10 ++++++++++
 src/test/ui/attributes/doc-attr.rs      |  8 ++++++++
 src/test/ui/attributes/doc-attr.stderr  | 20 +++++++++++++++++++-
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index a045b0d596d..5120edb2e35 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -605,6 +605,16 @@ impl CheckAttrVisitor<'tcx> {
                             return false;
                         }
                     }
+                } else {
+                    self.tcx.struct_span_lint_hir(
+                        INVALID_DOC_ATTRIBUTES,
+                        hir_id,
+                        meta.span(),
+                        |lint| {
+                            lint.build(&format!("unknown `doc` attribute")).emit();
+                        },
+                    );
+                    return false;
                 }
             }
         }
diff --git a/src/test/ui/attributes/doc-attr.rs b/src/test/ui/attributes/doc-attr.rs
index 3a584112973..261ba75dfcb 100644
--- a/src/test/ui/attributes/doc-attr.rs
+++ b/src/test/ui/attributes/doc-attr.rs
@@ -8,3 +8,11 @@
 //~^ ERROR unknown `doc` attribute
 //~^^ WARN
 pub fn foo() {}
+
+#[doc(123)]
+//~^ ERROR unknown `doc` attribute
+//~| WARN
+#[doc("hello", "bar")]
+//~^ ERROR unknown `doc` attribute
+//~| WARN
+fn bar() {}
diff --git a/src/test/ui/attributes/doc-attr.stderr b/src/test/ui/attributes/doc-attr.stderr
index 21479d25fc2..6bff40a7f70 100644
--- a/src/test/ui/attributes/doc-attr.stderr
+++ b/src/test/ui/attributes/doc-attr.stderr
@@ -13,6 +13,24 @@ 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
+  --> $DIR/doc-attr.rs:12:7
+   |
+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
+  --> $DIR/doc-attr.rs:15:7
+   |
+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 `as_ptr`
   --> $DIR/doc-attr.rs:3:8
    |
@@ -22,5 +40,5 @@ LL | #![doc(as_ptr)]
    = 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: aborting due to 2 previous errors
+error: aborting due to 4 previous errors