new lint: type_method_marked_deprecated (#1130)

part of: #57

Author: Frank-III

src/lints/type_method_marked_deprecated.ron

@@ -0,0 +1,72 @@
+SemverQuery(
+    id: "type_method_marked_deprecated",
+    human_readable_name: "type method #[deprecated] added",
+    description: "An inherent method has been newly marked with #[deprecated].",
+    required_update: Minor,
+    lint_level: Deny,
+    reference_link: Some("https://doc.rust-lang.org/reference/attributes/diagnostics.html#the-deprecated-attribute"),
+    query: r#"
+    {
+        CrateDiff {
+            current {
+                item {
+                    ... on ImplOwner {
+                        visibility_limit @filter(op: "=", value: ["$public"])
+                        name @output
+                        owner_type: __typename @tag @output
+
+                        importable_path {
+                            path @tag @output
+                            public_api @filter(op: "=", value: ["$true"])
+                        }
+
+                        inherent_impl {
+                            public_api_eligible @filter(op: "=", value: ["$true"])
+                            
+                            method {
+                                method_name: name @output @tag
+                                public_api_eligible @filter(op: "=", value: ["$true"])
+                                deprecated @filter(op: "=", value: ["$true"])
+
+                                span_: span @optional {
+                                    filename @output
+                                    begin_line @output
+                                    end_line @output
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            baseline {
+                item {
+                    ... on ImplOwner {
+                        visibility_limit @filter(op: "=", value: ["$public"])
+                        __typename @filter(op: "=", value: ["%owner_type"])
+
+                        importable_path {
+                            path @filter(op: "=", value: ["%path"])
+                            public_api @filter(op: "=", value: ["$true"])
+                        }
+
+                        inherent_impl {
+                            public_api_eligible @filter(op: "=", value: ["$true"])
+
+                            method {
+                                name @filter(op: "=", value: ["%method_name"])
+                                public_api_eligible @filter(op: "=", value: ["$true"])
+                                deprecated @filter(op: "!=", value: ["$true"])
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }"#,
+    arguments: {
+        "public": "public",
+        "true": true,
+    },
+    error_message: "A type method is now #[deprecated]. Downstream crates will get a compiler warning when using this method.",
+    per_result_error_template: Some("method {{join \"::\" path}}::{{method_name}} in {{span_filename}}:{{span_begin_line}}"),
+)

src/query.rs

@@ -1252,6 +1252,7 @@ add_lints!(
     type_allows_fewer_const_generic_params,
     type_allows_fewer_generic_type_params,
     type_marked_deprecated,
+    type_method_marked_deprecated,
     type_mismatched_generic_lifetimes,
     type_requires_more_const_generic_params,
     type_requires_more_generic_type_params,

test_crates/type_method_marked_deprecated/new/Cargo.toml

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

test_crates/type_method_marked_deprecated/new/src/enums.rs

@@ -0,0 +1,89 @@
+pub enum NormalEnum {
+    A,
+    B,
+}
+
+impl NormalEnum {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) -> bool {
+        matches!(self, NormalEnum::A)
+    }
+
+    #[deprecated = "Use to_string instead"]
+    pub fn method_with_message_to_be_deprecated(&self) -> String {
+        format!("{:?}", self)
+    }
+
+    #[deprecated]
+    pub fn already_deprecated_method(&self) {}
+
+    pub fn stays_normal(&self) {}
+}
+
+#[doc(hidden)]
+pub enum HiddenEnum {
+    A,
+}
+
+impl HiddenEnum {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+pub enum EnumWithHiddenImpl {
+    A,
+}
+
+#[doc(hidden)]
+impl EnumWithHiddenImpl {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+pub enum EnumWithHiddenMethod {
+    A,
+}
+
+impl EnumWithHiddenMethod {
+    #[doc(hidden)]
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+enum PrivateEnum {
+    A,
+}
+
+impl PrivateEnum {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+// Enum is deprecated but methods remain unchanged
+#[deprecated = "Use NewEnum instead"]
+pub enum EnumBecomesDeprecated {
+    A,
+    B,
+}
+
+impl EnumBecomesDeprecated {
+    // Methods intentionally not deprecated
+    pub fn method_stays_normal(&self) -> bool {
+        matches!(self, EnumBecomesDeprecated::A)
+    }
+
+    pub fn another_normal_method(&self) -> String {
+        format!("{:?}", self)
+    }
+}
+
+// Both enum and methods are deprecated
+#[deprecated]
+pub enum BothEnumAndMethodDeprecated {
+    A,
+}
+
+impl BothEnumAndMethodDeprecated {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}

test_crates/type_method_marked_deprecated/new/src/lib.rs

@@ -0,0 +1,3 @@
+pub mod enums;
+pub mod structs;
+pub mod unions;

test_crates/type_method_marked_deprecated/new/src/structs.rs

@@ -0,0 +1,87 @@
+pub struct NormalStruct {
+    value: i32,
+}
+
+impl NormalStruct {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) -> i32 {
+        self.value
+    }
+
+    #[deprecated = "Use new_method instead"]
+    pub fn method_with_message_to_be_deprecated(&self) -> String {
+        "hello".to_string()
+    }
+
+    #[deprecated]
+    pub fn already_deprecated_method(&self) {}
+
+    pub fn stays_normal(&self) {}
+}
+
+#[doc(hidden)]
+pub struct HiddenStruct {
+    value: i32,
+}
+
+impl HiddenStruct {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+pub struct StructWithHiddenImpl {
+    value: i32,
+}
+
+#[doc(hidden)]
+impl StructWithHiddenImpl {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+pub struct StructWithHiddenMethod {
+    value: i32,
+}
+
+impl StructWithHiddenMethod {
+    #[doc(hidden)]
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+struct PrivateStruct {
+    value: i32,
+}
+
+impl PrivateStruct {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+// Struct is deprecated but methods remain unchanged
+#[deprecated = "Use NewStruct instead"]
+pub struct StructBecomesDeprecated {
+    value: i32,
+}
+
+impl StructBecomesDeprecated {
+    // Methods intentionally not deprecated
+    pub fn method_stays_normal(&self) -> i32 {
+        self.value
+    }
+
+    pub fn another_normal_method(&self) -> String {
+        "hello".to_string()
+    }
+}
+
+// Both struct and methods are deprecated
+#[deprecated]
+pub struct BothStructAndMethodDeprecated {
+    value: i32,
+}
+
+impl BothStructAndMethodDeprecated {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}

test_crates/type_method_marked_deprecated/new/src/unions.rs

@@ -0,0 +1,90 @@
+pub union NormalUnion {
+    a: i32,
+    b: u32,
+}
+
+impl NormalUnion {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) -> i32 {
+        unsafe { self.a }
+    }
+
+    #[deprecated = "Use get_b instead"]
+    pub fn method_with_message_to_be_deprecated(&self) -> u32 {
+        unsafe { self.b }
+    }
+
+    #[deprecated]
+    pub fn already_deprecated_method(&self) {}
+
+    pub fn stays_normal(&self) {}
+}
+
+#[doc(hidden)]
+pub union HiddenUnion {
+    a: i32,
+}
+
+impl HiddenUnion {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+pub union UnionWithHiddenImpl {
+    a: i32,
+}
+
+#[doc(hidden)]
+impl UnionWithHiddenImpl {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+pub union UnionWithHiddenMethod {
+    a: i32,
+}
+
+impl UnionWithHiddenMethod {
+    #[doc(hidden)]
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+union PrivateUnion {
+    a: i32,
+}
+
+impl PrivateUnion {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}
+
+// Enum is deprecated but methods remain unchanged
+#[deprecated = "Use NewUnion instead"]
+pub union UnionBecomesDeprecated {
+    a: i32,
+    b: u32,
+}
+
+impl UnionBecomesDeprecated {
+    // Methods intentionally not deprecated
+    pub fn method_stays_normal(&self) -> i32 {
+        unsafe { self.a }
+    }
+
+    pub fn another_normal_method(&self) -> u32 {
+        unsafe { self.b }
+    }
+}
+
+// Both union and methods are deprecated
+#[deprecated]
+pub union BothUnionAndMethodDeprecated {
+    a: i32,
+    b: u32,
+}
+
+impl BothUnionAndMethodDeprecated {
+    #[deprecated]
+    pub fn method_to_be_deprecated(&self) {}
+}

test_crates/type_method_marked_deprecated/old/Cargo.toml

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