Fix for moving method to trait (#24)

* Do not report methods moved to a trait as breaking changes.

* Release 0.5.0.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cargo-semver-checks"
-version = "0.4.4"
+version = "0.5.0"
 edition = "2021"
 authors = ["Predrag Gruevski <obi1kenobi82@gmail.com>"]
 license = "Apache-2.0"

semver_tests/src/test_cases/item_missing.rs

@@ -21,4 +21,24 @@ impl Foo {
 
     #[cfg(not(feature = "inherent_method_missing"))]
     pub fn will_be_removed_method(&self) {}
+
+    #[cfg(not(feature = "inherent_method_missing"))]
+    pub fn moved_trait_provided_method(&self) {}
+
+    #[cfg(not(feature = "inherent_method_missing"))]
+    pub fn moved_method(&self) {}
+}
+
+// Moving an inherent method to an implemented trait should not be a breaking change,
+// both when the method is defined inside the trait and when it's implemented externally.
+#[cfg(feature = "inherent_method_missing")]
+pub trait Bar {
+    fn moved_trait_provided_method(&self) {}
+
+    fn moved_method(&self);
+}
+
+#[cfg(feature = "inherent_method_missing")]
+impl Bar for Foo {
+    fn moved_method(&self) {}
 }

src/adapter.rs

@@ -1,6 +1,8 @@
-use std::sync::Arc;
+use std::{collections::BTreeSet, sync::Arc};
 
-use rustdoc_types::{Crate, Enum, Function, Impl, Item, Method, Span, Struct, Type, Variant};
+use rustdoc_types::{
+    Crate, Enum, Function, Id, Impl, Item, ItemEnum, Method, Span, Struct, Type, Variant,
+};
 use trustfall_core::{
     interpreter::{Adapter, DataContext, InterpretedQuery},
     ir::{EdgeParameters, Eid, FieldValue, Vid},
@@ -714,7 +716,33 @@ impl<'a> Adapter<'a> for RustdocAdapter<'a> {
                                 };
 
                                 let impl_token = token.as_impl().expect("not an Impl token");
-                                Box::new(impl_token.items.iter().filter_map(move |item_id| {
+                                let provided_methods: Box<dyn Iterator<Item = &Id>> = if impl_token.provided_trait_methods.is_empty() {
+                                    Box::new(std::iter::empty())
+                                } else {
+                                    let method_names: BTreeSet<&str> = impl_token.provided_trait_methods.iter().map(|x| x.as_str()).collect();
+
+                                    let trait_type = impl_token.trait_.as_ref().expect("no trait but provided_trait_methods was non-empty");
+                                    let trait_item = match trait_type {
+                                        Type::ResolvedPath { name: _, id, args: _, param_names: _ } => {
+                                            &item_index[id]
+                                        }
+                                        _ => unimplemented!("found provided_trait_methods when the trait was not a ResolvedPath: {trait_type:?}"),
+                                    };
+
+                                    if let ItemEnum::Trait(trait_item) = &trait_item.inner {
+                                        Box::new(trait_item.items.iter().filter(move |item_id| {
+                                            let next_item = &item_index[*item_id];
+                                            if let Some(name) = &next_item.name {
+                                                method_names.contains(name.as_str())
+                                            } else {
+                                                false
+                                            }
+                                        }))
+                                    } else {
+                                        unreachable!("found a non-trait type {trait_item:?}");
+                                    }
+                                };
+                                Box::new(provided_methods.chain(impl_token.items.iter()).filter_map(move |item_id| {
                                     let next_item = &item_index[item_id];
                                     match &next_item.inner {
                                         rustdoc_types::ItemEnum::Method(..) => {

src/queries/inherent_method_missing.ron

@@ -41,9 +41,12 @@ SemverQuery(
                             path @filter(op: "=", value: ["%path"])
                         }
 
-                        inherent_impl @fold @transform(op: "count") @filter(op: "=", value: ["$zero"]) {
+                        # We use "impl" instead of "inherent_impl" here because moving
+                        # an inherently-implemented method to a trait is not necessarily
+                        # a breaking change, so we don't want to report it.
+                        impl @fold @transform(op: "count") @filter(op: "=", value: ["$zero"]) {
                             method {
-                                visibility_limit @filter(op: "=", value: ["$public"])
+                                visibility_limit @filter(op: "one_of", value: ["$public_or_default"])
                                 name @filter(op: "=", value: ["%method_name"])
                             }
                         }
@@ -54,6 +57,7 @@ SemverQuery(
     }"#,
     arguments: {
         "public": "public",
+        "public_or_default": ["public", "default"],
         "zero": 0,
     },
     error_message: "A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.",