style: stricter linting

lib/src/bindings/reference.dart

@@ -249,7 +249,7 @@ Pointer<git_reference> createDirect({
 
   if (error < 0) {
     calloc.free(out);
-    throw (LibGit2Error(libgit2.git_error_last()));
+    throw LibGit2Error(libgit2.git_error_last());
   } else {
     return out.value;
   }
@@ -309,7 +309,7 @@ Pointer<git_reference> createSymbolic({
 
   if (error < 0) {
     calloc.free(out);
-    throw (LibGit2Error(libgit2.git_error_last()));
+    throw LibGit2Error(libgit2.git_error_last());
   } else {
     return out.value;
   }

lib/src/config.dart

@@ -211,12 +211,12 @@ class _ConfigIterator implements Iterator<ConfigEntry> {
   /// Pointer to memory address for allocated config iterator.
   final Pointer<git_config_iterator> _iteratorPointer;
 
-  ConfigEntry? _currentEntry;
+  late ConfigEntry _currentEntry;
   int error = 0;
   final entry = calloc<Pointer<git_config_entry>>();
 
   @override
-  ConfigEntry get current => _currentEntry!;
+  ConfigEntry get current => _currentEntry;
 
   @override
   bool moveNext() {

lib/src/index.dart

@@ -394,12 +394,12 @@ class _IndexIterator implements Iterator<IndexEntry> {
   }
 
   final Pointer<git_index> _indexPointer;
-  IndexEntry? _currentEntry;
+  late IndexEntry _currentEntry;
   int _index = 0;
   late final int count;
 
   @override
-  IndexEntry get current => _currentEntry!;
+  IndexEntry get current => _currentEntry;
 
   @override
   bool moveNext() {

lib/src/oid.dart

@@ -5,7 +5,9 @@ import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/odb.dart' as odb_bindings;
 import 'package:libgit2dart/src/bindings/oid.dart' as bindings;
 import 'package:libgit2dart/src/util.dart';
+import 'package:meta/meta.dart';
 
+@immutable
 class Oid {
   /// Initializes a new instance of [Oid] class from provided
   /// pointer to Oid object in memory.

lib/src/reference.dart

@@ -280,21 +280,20 @@ class Reference {
   /// Repository where a reference resides.
   Repository get owner => Repository(bindings.owner(_refPointer));
 
-  @override
-  bool operator ==(Object other) {
-    return (other is Reference) &&
-        bindings.compare(
-          ref1Pointer: _refPointer,
-          ref2Pointer: other._refPointer,
-        );
+  /// Compares two references.
+  bool equals(Reference other) {
+    return bindings.compare(
+      ref1Pointer: _refPointer,
+      ref2Pointer: other._refPointer,
+    );
   }
 
+  /// Compares two references.
+  bool notEquals(Reference other) => !equals(other);
+
   /// Releases memory allocated for reference object.
   void free() => bindings.free(_refPointer);
 
-  @override // coverage:ignore-line
-  int get hashCode => _refPointer.address.hashCode; // coverage:ignore-line
-
   @override
   String toString() {
     return 'Reference{name: $name, target: $target, type: $type, '

lib/src/reflog.dart

@@ -129,12 +129,12 @@ class _RefLogIterator implements Iterator<RefLogEntry> {
   /// Pointer to memory address for allocated reflog object.
   final Pointer<git_reflog> _reflogPointer;
 
-  RefLogEntry? _currentEntry;
+  late RefLogEntry _currentEntry;
   int _index = 0;
   late final int _count;
 
   @override
-  RefLogEntry get current => _currentEntry!;
+  RefLogEntry get current => _currentEntry;
 
   @override
   bool moveNext() {

lib/src/signature.dart

@@ -4,7 +4,9 @@ import 'package:libgit2dart/libgit2dart.dart';
 import 'package:libgit2dart/src/bindings/libgit2_bindings.dart';
 import 'package:libgit2dart/src/bindings/signature.dart' as bindings;
 import 'package:libgit2dart/src/util.dart';
+import 'package:meta/meta.dart';
 
+@immutable
 class Signature {
   /// Initializes a new instance of [Signature] class from provided pointer to
   /// signature object in memory.

lib/src/util.dart

@@ -18,7 +18,7 @@ String getLibName() {
     ext = 'dll';
   } else if (Platform.isMacOS) {
     ext = 'dylib';
-  } else if (!(Platform.isLinux)) {
+  } else if (!Platform.isLinux) {
     throw Exception('Unsupported platform.');
   }