Add lint macro_now_doc_hidden

src/lints/declarative_macro_missing.ron

@@ -25,7 +25,6 @@ SemverQuery(
             current @fold @transform(op: "count") @filter(op: "=", value: ["$zero"]) {
                 item {
                     ... on Macro {
-                        visibility_limit @filter(op: "=", value: ["$public"])
                         name @filter(op: "=", value: ["%name"])
                     }
                 }
@@ -37,7 +36,7 @@ SemverQuery(
         "zero": 0,
         "true": true,
     },
-    error_message: "A publicly-visible `macro_rules` declarative macro cannot be imported by its prior name. A `#[macro_export]` may have been removed, or the macro itself may have been renamed or removed entirely.",
+    error_message: "A `macro_rules` declarative macro cannot be imported by its prior name. The macro may have been renamed or removed entirely.",
     per_result_error_template:  Some("macro_rules! {{name}}, previously in file {{span_filename}}:{{span_begin_line}}"),
     witness: (
         hint_template: r#"{{name}}!(...);"#

src/lints/macro_now_doc_hidden.ron

@@ -0,0 +1,40 @@
+SemverQuery(
+    id: "macro_now_doc_hidden",
+    human_readable_name: "macro is now #[doc(hidden)]",
+    description: "A declarative macro that was previously part of the public API is now #[doc(hidden)], requiring downstream users to acknowledge their reliance on non-public APIs.",
+    required_update: Major,
+    lint_level: Deny,
+    reference_link: Some("https://doc.rust-lang.org/rustdoc/write-documentation/the-doc-attribute.html#hidden"),
+    query: r#"
+    {
+        CrateDiff {
+            baseline {
+                item {
+                    ... on Macro {
+                        name @output @tag
+                        public_api_eligible @filter(op: "=", value: ["$true"])
+                    }
+                }
+            }
+            current {
+                item {
+                    ... on Macro {
+                        name @filter(op: "=", value: ["%name"])
+                        doc_hidden @filter(op: "=", value: ["$true"])
+                        public_api_eligible @filter(op: "!=", value: ["$true"])
+                        span_: span @optional {
+                            filename @output
+                            begin_line @output
+                        }
+                    }
+                }
+            }
+        }
+    }"#,
+    arguments: {
+        "true": true,
+    },
+    error_message: "A macro that was previously part of the public API is now #[doc(hidden)].",
+    per_result_error_template: Some("macro {{name}} in {{span_filename}}:{{span_begin_line}}"),
+    witness: None,
+)

src/query.rs

@@ -1095,6 +1095,7 @@ add_lints!(
     inherent_method_must_use_added,
     inherent_method_now_doc_hidden,
     inherent_method_unsafe_added,
+    macro_now_doc_hidden,
     method_parameter_count_changed,
     module_missing,
     non_exhaustive_struct_changed_type,

test_crates/macro_now_doc_hidden/new/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+publish = false
+name = "macro_now_doc_hidden"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

test_crates/macro_now_doc_hidden/new/src/lib.rs

@@ -0,0 +1,40 @@
+/// Now hidden from docs
+#[doc(hidden)]
+#[macro_export]
+macro_rules! will_be_hidden {
+    ($val:expr, $opts:expr) => {
+        println!("Processing {} with {:?}", $val, $opts);
+    };
+}
+
+/// A macro that stays public
+#[macro_export]
+macro_rules! stays_public {
+    () => {
+        println!("This macro remains public");
+    };
+}
+
+// Already hidden macro that changes implementation but stays hidden
+#[doc(hidden)]
+#[macro_export]
+macro_rules! already_hidden {
+    () => {
+        println!("Version 2");
+    };
+}
+
+// Non-exported macro that becomes hidden - should not trigger
+#[doc(hidden)]
+macro_rules! non_exported_becomes_hidden {
+    () => {
+        println!("Not exported and now hidden");
+    };
+}
+
+// Macro that was exported but is no longer exported - should not trigger
+macro_rules! becomes_non_exported {
+    () => {
+        println!("No longer exported");
+    };
+}

test_crates/macro_now_doc_hidden/old/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+publish = false
+name = "macro_now_doc_hidden"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

test_crates/macro_now_doc_hidden/old/src/lib.rs

@@ -0,0 +1,40 @@
+/// A macro that will become hidden
+#[macro_export]
+macro_rules! will_be_hidden {
+    ($val:expr, $opts:expr) => {
+        println!("Processing {} with {:?}", $val, $opts);
+    };
+}
+
+/// A macro that stays public
+#[macro_export]
+macro_rules! stays_public {
+    () => {
+        println!("This macro remains public");
+    };
+}
+
+// Already hidden macro that changes implementation but stays hidden
+#[doc(hidden)]
+#[macro_export]
+macro_rules! already_hidden {
+    () => {
+        println!("Version 1");
+    };
+}
+
+// Non-exported macro that becomes hidden - should not trigger
+/// Some documentation
+macro_rules! non_exported_becomes_hidden {
+    () => {
+        println!("Not exported");
+    };
+}
+
+// Exported macro that becomes non-exported but not doc(hidden) - should not trigger
+#[macro_export]
+macro_rules! becomes_non_exported {
+    () => {
+        println!("Will become non-exported");
+    };
+}

test_outputs/query_execution/declarative_macro_missing.snap

@@ -1,6 +1,7 @@
 ---
 source: src/query.rs
 expression: "&query_execution_results"
+snapshot_kind: text
 ---
 {
   "./test_crates/declarative_macro_missing/": [
@@ -9,10 +10,5 @@ expression: "&query_execution_results"
       "span_begin_line": Uint64(2),
       "span_filename": String("src/lib.rs"),
     },
-    {
-      "name": String("will_no_longer_be_exported"),
-      "span_begin_line": Uint64(7),
-      "span_filename": String("src/lib.rs"),
-    },
   ],
 }

test_outputs/query_execution/macro_now_doc_hidden.snap

@@ -0,0 +1,21 @@
+---
+source: src/query.rs
+expression: "&query_execution_results"
+snapshot_kind: text
+---
+{
+  "./test_crates/declarative_macro_missing/": [
+    {
+      "name": String("became_doc_hidden"),
+      "span_begin_line": Uint64(7),
+      "span_filename": String("src/lib.rs"),
+    },
+  ],
+  "./test_crates/macro_now_doc_hidden/": [
+    {
+      "name": String("will_be_hidden"),
+      "span_begin_line": Uint64(4),
+      "span_filename": String("src/lib.rs"),
+    },
+  ],
+}