chore: fix last clippy lints and enforce in CI

.github/workflows/bindgen.yml

@@ -12,25 +12,27 @@ on:
       - main
 
 jobs:
-  rustfmt-clippy:
+  rustfmt:
     runs-on: ubuntu-latest
-
     steps:
       - uses: actions/checkout@v4
 
       - name: Install nightly
         uses: dtolnay/rust-toolchain@master
         with:
-          # TODO: Should ideally be stable, but we use some nightly-only
-          # features.
           toolchain: nightly
-          components: rustfmt, clippy
+          components: rustfmt
 
       - name: Run rustfmt
-        run: cargo fmt -- --check
+        run: cargo +nightly fmt -- --check
+
+  clippy:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
 
       - name: Run clippy
-        run: cargo clippy --all-targets --workspace --exclude bindgen-integration --exclude tests_expectations
+        run: cargo clippy --all-targets --workspace --exclude bindgen-integration --exclude tests_expectations -- -D warnings
 
   msrv:
     runs-on: ubuntu-latest
@@ -64,12 +66,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install stable
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: stable
-
-      - name: Check without default features 
+      - name: Check without default features
         run: cargo check -p bindgen --no-default-features --features=runtime 
 
   docs:
@@ -79,12 +76,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install stable
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: stable
-
-      - name: Generate documentation for `bindgen` 
+      - name: Generate documentation for `bindgen`
         run: cargo doc --document-private-items --no-deps -p bindgen 
 
       - name: Generate documentation for `bindgen-cli` 
@@ -95,11 +87,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install stable
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: stable
-
       # TODO: Actually run quickchecks once `bindgen` is reliable enough.
       - name: Build quickcheck tests
         run: cd bindgen-tests/tests/quickchecking && cargo test
@@ -112,11 +99,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install stable
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: stable
-
       - name: Test expectations
         run: cd bindgen-tests/tests/expectations && cargo test
 
@@ -174,21 +156,6 @@ jobs:
           BINDGEN_RUST_FOR_LINUX_TEST: ${{matrix.os == 'ubuntu-latest' && matrix.llvm_version == '16.0' && matrix.feature_extra_asserts == 0 && 1 || 0}}
         run: ./ci/test.sh
 
-  check-cfg:
-    runs-on: ubuntu-latest
-    env:
-      RUSTFLAGS: -D warnings
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Install nightly
-        uses: dtolnay/rust-toolchain@master
-        with:
-          toolchain: nightly
-
-      - name: Check cfg
-        run: cargo check -Z unstable-options -Z check-cfg
-
   test-book:
     runs-on: ubuntu-latest
     steps:
@@ -221,7 +188,7 @@ jobs:
   # separately.
   success:
     runs-on: ubuntu-latest
-    needs: [rustfmt-clippy, msrv, minimal, docs, quickchecking, test-expectations, test, check-cfg, test-book, test-no-headers]
+    needs: [rustfmt, clippy, msrv, minimal, docs, quickchecking, test-expectations, test, test-book, test-no-headers]
     # GitHub branch protection is exceedingly silly and treats "jobs skipped
     # because a dependency failed" as success. So we have to do some
     # contortions to ensure the job fails if any of its dependencies fails.

bindgen-tests/build.rs

@@ -23,7 +23,7 @@ pub fn main() {
 
     for entry in entries {
         // TODO: file_is_cpp() in bindgen/lib.rs checks for hpp,hxx,hh, and h++ - should this be consistent?
-        if entry.path().extension().map_or(false, |ext| {
+        if entry.path().extension().is_some_and(|ext| {
             ext.eq_ignore_ascii_case("h") || ext.eq_ignore_ascii_case("hpp")
         }) {
             let func = entry

bindgen-tests/tests/parse_callbacks/item_discovery_callback/mod.rs

@@ -20,7 +20,7 @@ impl ParseCallbacks for ItemDiscovery {
 
 fn test_item_discovery_callback(
     header: &str,
-    expected: HashMap<DiscoveredItemId, DiscoveredItem>,
+    expected: &HashMap<DiscoveredItemId, DiscoveredItem>,
 ) {
     let discovery = ItemDiscovery::default();
     let info = Rc::clone(&discovery.0);
@@ -34,7 +34,7 @@ fn test_item_discovery_callback(
         .generate()
         .expect("TODO: panic message");
 
-    compare_item_caches(&info.borrow(), &expected);
+    compare_item_caches(&info.borrow(), expected);
 }
 
 #[test]
@@ -103,7 +103,7 @@ fn test_item_discovery_callback_c() {
         ),
     ]);
     test_item_discovery_callback(
-        "/tests/parse_callbacks/item_discovery_callback/header_item_discovery.h", expected);
+        "/tests/parse_callbacks/item_discovery_callback/header_item_discovery.h", &expected);
 }
 
 #[test]
@@ -125,7 +125,7 @@ fn test_item_discovery_callback_cpp() {
         ),
     ]);
     test_item_discovery_callback(
-        "/tests/parse_callbacks/item_discovery_callback/header_item_discovery.hpp", expected);
+        "/tests/parse_callbacks/item_discovery_callback/header_item_discovery.hpp", &expected);
 }
 
 pub fn compare_item_caches(generated: &ItemCache, expected: &ItemCache) {

bindgen-tests/tests/quickchecking/src/fuzzers.rs

@@ -1,5 +1,6 @@
 use quickcheck::{Arbitrary, Gen};
 use std::fmt;
+use std::fmt::Write as _;
 
 /// `BaseTypeC` is used in generation of C headers to represent the C language's
 /// primitive types as well as `void*`.
@@ -223,11 +224,10 @@ impl Arbitrary for DeclarationListC {
 /// Enables to string and format for `DeclarationListC` types.
 impl fmt::Display for DeclarationListC {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let mut display = String::new();
         for decl in &self.decls {
-            display += &format!("{decl}");
+            write!(f, "{decl}")?;
         }
-        write!(f, "{display}")
+        Ok(())
     }
 }
 
@@ -330,7 +330,7 @@ impl Arbitrary for ArrayDimensionC {
 
         for _ in 1..dimensions {
             // 16 is an arbitrary "not too big" number for capping array size.
-            def += &format!("[{}]", gen_range(g, lower_bound, 16));
+            let _ = write!(def, "[{}]", gen_range(g, lower_bound, 16));
         }
         ArrayDimensionC { def }
     }
@@ -347,7 +347,7 @@ impl fmt::Display for ArrayDimensionC {
 /// identifiers unique.
 impl MakeUnique for BasicTypeDeclarationC {
     fn make_unique(&mut self, stamp: usize) {
-        self.ident_id += &format!("_{stamp}");
+        let _ = write!(self.ident_id, "_{stamp}");
     }
 }
 
@@ -384,7 +384,7 @@ impl fmt::Display for BasicTypeDeclarationC {
 /// identifiers unique.
 impl MakeUnique for StructDeclarationC {
     fn make_unique(&mut self, stamp: usize) {
-        self.ident_id += &format!("_{stamp}");
+        let _ = write!(self.ident_id, "_{stamp}");
     }
 }
 
@@ -432,7 +432,7 @@ impl fmt::Display for StructDeclarationC {
 /// identifiers unique.
 impl MakeUnique for UnionDeclarationC {
     fn make_unique(&mut self, stamp: usize) {
-        self.ident_id += &format!("_{stamp}");
+        let _ = write!(self.ident_id, "_{stamp}");
     }
 }
 
@@ -480,7 +480,7 @@ impl fmt::Display for UnionDeclarationC {
 /// `FunctionPointerDeclarationC` identifiers unique.
 impl MakeUnique for FunctionPointerDeclarationC {
     fn make_unique(&mut self, stamp: usize) {
-        self.ident_id += &format!("_{stamp}");
+        let _ = write!(self.ident_id, "_{stamp}");
     }
 }
 
@@ -517,7 +517,7 @@ impl fmt::Display for FunctionPointerDeclarationC {
 /// identifiers unique.
 impl MakeUnique for FunctionPrototypeC {
     fn make_unique(&mut self, stamp: usize) {
-        self.ident_id += &format!("_{stamp}");
+        let _ = write!(self.ident_id, "_{stamp}");
     }
 }
 
@@ -586,14 +586,13 @@ impl Arbitrary for ParameterListC {
 /// Enables to string and format for `ParameterListC` types.
 impl fmt::Display for ParameterListC {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let mut display = String::new();
         for (i, p) in self.params.iter().enumerate() {
             match i {
-                0 => display += &format!("{p}"),
-                _ => display += &format!(",{p}"),
+                0 => write!(f, "{p}")?,
+                _ => write!(f, ",{p}")?,
             }
         }
-        write!(f, "{display}")
+        Ok(())
     }
 }
 
@@ -612,11 +611,10 @@ impl Arbitrary for HeaderC {
 /// Enables to string and format for `HeaderC` types.
 impl fmt::Display for HeaderC {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let mut display = String::new();
         for decl in &self.def.decls {
-            display += &format!("{decl}");
+            write!(f, "{decl}")?;
         }
-        write!(f, "{display}")
+        Ok(())
     }
 }
 

bindgen-tests/tests/tests.rs

@@ -27,7 +27,7 @@ fn should_overwrite_expected() -> bool {
             return true;
         }
         assert!(
-            var == "0" || var == "",
+            var == "0" || var.is_empty(),
             "Invalid value of BINDGEN_OVERWRITE_EXPECTED"
         );
     }
@@ -57,7 +57,7 @@ fn error_diff_mismatch(
     if let Some(var) = env::var_os("BINDGEN_TESTS_DIFFTOOL") {
         //usecase: var = "meld" -> You can hand check differences
         let Some(std::path::Component::Normal(name)) =
-            filename.components().last()
+            filename.components().next_back()
         else {
             panic!("Why is the header variable so weird?")
         };
@@ -187,7 +187,7 @@ fn compare_generated_header(
             header.display(),
             looked_at,
         ),
-    };
+    }
 
     let (builder, roundtrip_builder) = builder.into_builder(check_roundtrip)?;
 

bindgen/codegen/mod.rs

@@ -3075,7 +3075,7 @@ impl Method {
                     parent: parent_id,
                     final_name: name.clone(),
                 },
-            )
+            );
         });
 
         let mut function_name = function_item.canonical_name(ctx);
@@ -3138,7 +3138,7 @@ impl Method {
             exprs[0] = quote! {
                 self
             };
-        };
+        }
 
         let call = quote! {
             #function_name (#( #exprs ),* )
@@ -3282,7 +3282,7 @@ impl FromStr for EnumVariation {
 struct EnumBuilder {
     /// Type identifier of the enum.
     ///
-    /// This is the base name, i.e. for ModuleConst enums, this does not include the module name.
+    /// This is the base name, i.e. for `ModuleConst` enums, this does not include the module name.
     enum_type: Ident,
     /// Attributes applying to the enum type
     attrs: Vec<proc_macro2::TokenStream>,
@@ -3453,7 +3453,7 @@ impl EnumBuilder {
     }
 
     fn newtype_bitfield_impl(
-        prefix: Ident,
+        prefix: &Ident,
         rust_ty: &syn::Type,
     ) -> proc_macro2::TokenStream {
         let rust_ty_name = &rust_ty;
@@ -3593,7 +3593,7 @@ impl EnumBuilder {
 
                 let prefix = ctx.trait_prefix();
                 let bitfield_impl_opt = is_bitfield
-                    .then(|| Self::newtype_bitfield_impl(prefix, rust_ty));
+                    .then(|| Self::newtype_bitfield_impl(&prefix, rust_ty));
 
                 quote! {
                     // Previously variant impls where before the enum definition.
@@ -4625,7 +4625,7 @@ impl CodeGenerator for Function {
             FunctionKind::Method(ref method_kind) => {
                 method_kind.is_pure_virtual()
             }
-            _ => false,
+            FunctionKind::Function => false,
         };
         if is_pure_virtual && !ctx.options().generate_pure_virtual_functions {
             // Pure virtual methods have no actual symbol, so we can't generate
@@ -4729,7 +4729,7 @@ impl CodeGenerator for Function {
                 mangled_name,
                 Some(abi),
             ))
-            .then(|| mangled_name)
+            .then_some(mangled_name)
         });
 
         if let Some(link_name) = link_name_attr {

bindgen/codegen/serialize.rs

@@ -368,7 +368,7 @@ impl<'a> CSerialize<'a> for Type {
                 match comp_info.kind() {
                     CompKind::Struct => write!(writer, "struct {name}")?,
                     CompKind::Union => write!(writer, "union {name}")?,
-                };
+                }
             }
             TypeKind::Enum(_enum_ty) => {
                 if self.is_const() {
@@ -384,7 +384,7 @@ impl<'a> CSerialize<'a> for Type {
                     loc: get_loc(item),
                 })
             }
-        };
+        }
 
         if !stack.is_empty() {
             write!(writer, " ")?;

bindgen/codegen/struct_layout.rs

@@ -266,11 +266,11 @@ impl<'a> StructLayoutTracker<'a> {
             }
         };
 
-        if !is_union {
-            self.latest_offset += field_layout.size;
-        } else {
+        if is_union {
             self.latest_offset =
                 cmp::max(self.latest_offset, field_layout.size);
+        } else {
+            self.latest_offset += field_layout.size;
         }
         self.latest_field_layout = Some(field_layout);
         self.max_field_align =