Port member initialization from constructor to declaration (C++11)

Using `clang-tidy`'s `modernize-use-default-member-init` check and
manual review of the changes, and some extra manual changes that
`clang-tidy` failed to do.

Also went manually through all of `core` to find occurrences that
`clang-tidy` couldn't handle, especially all initializations done
in a constructor without using initializer lists.

10 files changed, 63 insertions, 131 deletions

diff --git a/modules/mono/csharp_script.h b/modules/mono/csharp_script.h
index c9ea482c36..280c981a47 100644
--- a/modules/mono/csharp_script.h
+++ b/modules/mono/csharp_script.h
@@ -326,17 +326,13 @@ public:
 };
 
 struct CSharpScriptBinding {
-	bool inited;
+	bool inited = false;
 	StringName type_name;
-	GDMonoClass *wrapper_class;
+	GDMonoClass *wrapper_class = nullptr;
 	MonoGCHandleData gchandle;
-	Object *owner;
+	Object *owner = nullptr;
 
-	CSharpScriptBinding() :
-			inited(false),
-			wrapper_class(nullptr),
-			owner(nullptr) {
-	}
+	CSharpScriptBinding() {}
 };
 
 class ManagedCallableMiddleman : public Object {
diff --git a/modules/mono/editor/bindings_generator.h b/modules/mono/editor/bindings_generator.h
index 5672231e9a..9aad9622d9 100644
--- a/modules/mono/editor/bindings_generator.h
+++ b/modules/mono/editor/bindings_generator.h
@@ -85,16 +85,12 @@ class BindingsGenerator {
 
 	struct TypeReference {
 		StringName cname;
-		bool is_enum;
+		bool is_enum = false;
 
-		TypeReference() :
-				is_enum(false) {
-		}
+		TypeReference() {}
 
 		TypeReference(const StringName &p_cname) :
-				cname(p_cname),
-				is_enum(false) {
-		}
+				cname(p_cname) {}
 	};
 
 	struct ArgumentInterface {
@@ -107,7 +103,7 @@ class BindingsGenerator {
 		TypeReference type;
 
 		String name;
-		DefaultParamMode def_param_mode;
+		DefaultParamMode def_param_mode = CONSTANT;
 
 		/**
 		 * Determines the expression for the parameter default value.
@@ -116,9 +112,7 @@ class BindingsGenerator {
 		 */
 		String default_argument;
 
-		ArgumentInterface() {
-			def_param_mode = CONSTANT;
-		}
+		ArgumentInterface() {}
 	};
 
 	struct MethodInterface {
@@ -138,19 +132,19 @@ class BindingsGenerator {
 		/**
 		 * Determines if the method has a variable number of arguments (VarArg)
 		 */
-		bool is_vararg;
+		bool is_vararg = false;
 
 		/**
 		 * Virtual methods ("virtual" as defined by the Godot API) are methods that by default do nothing,
 		 * but can be overridden by the user to add custom functionality.
 		 * e.g.: _ready, _process, etc.
 		 */
-		bool is_virtual;
+		bool is_virtual = false;
 
 		/**
 		 * Determines if the call should fallback to Godot's object.Call(string, params) in C#.
 		 */
-		bool requires_object_call;
+		bool requires_object_call = false;
 
 		/**
 		 * Determines if the method visibility is 'internal' (visible only to files in the same assembly).
@@ -158,27 +152,20 @@ class BindingsGenerator {
 		 * but are required by properties as getters or setters.
 		 * Methods that are not meant to be exposed are those that begin with underscore and are not virtual.
 		 */
-		bool is_internal;
+		bool is_internal = false;
 
 		List<ArgumentInterface> arguments;
 
-		const DocData::MethodDoc *method_doc;
+		const DocData::MethodDoc *method_doc = nullptr;
 
-		bool is_deprecated;
+		bool is_deprecated = false;
 		String deprecation_message;
 
 		void add_argument(const ArgumentInterface &argument) {
 			arguments.push_back(argument);
 		}
 
-		MethodInterface() {
-			is_vararg = false;
-			is_virtual = false;
-			requires_object_call = false;
-			is_internal = false;
-			method_doc = nullptr;
-			is_deprecated = false;
-		}
+		MethodInterface() {}
 	};
 
 	struct SignalInterface {
@@ -192,19 +179,16 @@ class BindingsGenerator {
 
 		List<ArgumentInterface> arguments;
 
-		const DocData::MethodDoc *method_doc;
+		const DocData::MethodDoc *method_doc = nullptr;
 
-		bool is_deprecated;
+		bool is_deprecated = false;
 		String deprecation_message;
 
 		void add_argument(const ArgumentInterface &argument) {
 			arguments.push_back(argument);
 		}
 
-		SignalInterface() {
-			method_doc = nullptr;
-			is_deprecated = false;
-		}
+		SignalInterface() {}
 	};
 
 	struct TypeInterface {
@@ -225,26 +209,26 @@ class BindingsGenerator {
 		 */
 		String proxy_name;
 
-		ClassDB::APIType api_type;
+		ClassDB::APIType api_type = ClassDB::API_NONE;
 
-		bool is_enum;
-		bool is_object_type;
-		bool is_singleton;
-		bool is_reference;
+		bool is_enum = false;
+		bool is_object_type = false;
+		bool is_singleton = false;
+		bool is_reference = false;
 
 		/**
 		 * Used only by Object-derived types.
 		 * Determines if this type is not abstract (incomplete).
 		 * e.g.: CanvasItem cannot be instantiated.
 		 */
-		bool is_instantiable;
+		bool is_instantiable = false;
 
 		/**
 		 * Used only by Object-derived types.
 		 * Determines if the C# class owns the native handle and must free it somehow when disposed.
 		 * e.g.: Reference types must notify when the C# instance is disposed, for proper refcounting.
 		 */
-		bool memory_own;
+		bool memory_own = false;
 
 		/**
 		 * This must be set to true for any struct bigger than 32-bits. Those cannot be passed/returned by value
@@ -252,7 +236,7 @@ class BindingsGenerator {
 		 * In this case, [c_out] and [cs_out] must have a different format, explained below.
 		 * The Mono IL interpreter icall trampolines don't support passing structs bigger than 32-bits by value (at least not on WASM).
 		 */
-		bool ret_as_byref_arg;
+		bool ret_as_byref_arg = false;
 
 		// !! The comments of the following fields make reference to other fields via square brackets, e.g.: [field_name]
 		// !! When renaming those fields, make sure to rename their references in the comments
@@ -279,7 +263,7 @@ class BindingsGenerator {
 		 * Formatting elements:
 		 * %0 or %s: name of the parameter
 		 */
-		String c_arg_in;
+		String c_arg_in = "%s";
 
 		/**
 		 * One or more statements that determine how a variable of this type is returned from a function.
@@ -362,7 +346,7 @@ class BindingsGenerator {
 		 */
 		String im_type_out;
 
-		const DocData::ClassDoc *class_doc;
+		const DocData::ClassDoc *class_doc = nullptr;
 
 		List<ConstantInterface> constants;
 		List<EnumInterface> enums;
@@ -482,24 +466,7 @@ class BindingsGenerator {
 			r_enum_itype.class_doc = &EditorHelp::get_doc_data()->class_list[r_enum_itype.proxy_name];
 		}
 
-		TypeInterface() {
-
-			api_type = ClassDB::API_NONE;
-
-			is_enum = false;
-			is_object_type = false;
-			is_singleton = false;
-			is_reference = false;
-			is_instantiable = false;
-
-			memory_own = false;
-
-			ret_as_byref_arg = false;
-
-			c_arg_in = "%s";
-
-			class_doc = nullptr;
-		}
+		TypeInterface() {}
 	};
 
 	struct InternalCall {
@@ -532,8 +499,8 @@ class BindingsGenerator {
 		}
 	};
 
-	bool log_print_enabled;
-	bool initialized;
+	bool log_print_enabled = true;
+	bool initialized = false;
 
 	OrderedHashMap<StringName, TypeInterface> obj_types;
 
@@ -697,9 +664,7 @@ public:
 
 	static void handle_cmdline_args(const List<String> &p_cmdline_args);
 
-	BindingsGenerator() :
-			log_print_enabled(true),
-			initialized(false) {
+	BindingsGenerator() {
 		_initialize();
 	}
 };
diff --git a/modules/mono/mono_gc_handle.h b/modules/mono/mono_gc_handle.h
index fbcb405b0d..005ee52b35 100644
--- a/modules/mono/mono_gc_handle.h
+++ b/modules/mono/mono_gc_handle.h
@@ -47,8 +47,8 @@ enum class GCHandleType : char {
 
 // Manual release of the GC handle must be done when using this struct
 struct MonoGCHandleData {
-	uint32_t handle;
-	gdmono::GCHandleType type;
+	uint32_t handle = 0;
+	gdmono::GCHandleType type = gdmono::GCHandleType::NIL;
 
 	_FORCE_INLINE_ bool is_released() const { return !handle; }
 	_FORCE_INLINE_ bool is_weak() const { return type == gdmono::GCHandleType::WEAK_HANDLE; }
@@ -68,10 +68,7 @@ struct MonoGCHandleData {
 
 	MonoGCHandleData(const MonoGCHandleData &) = default;
 
-	MonoGCHandleData() :
-			handle(0),
-			type(gdmono::GCHandleType::NIL) {
-	}
+	MonoGCHandleData() {}
 
 	MonoGCHandleData(uint32_t p_handle, gdmono::GCHandleType p_type) :
 			handle(p_handle),
diff --git a/modules/mono/mono_gd/gd_mono.h b/modules/mono/mono_gd/gd_mono.h
index 153ae891f7..3b0be4c180 100644
--- a/modules/mono/mono_gd/gd_mono.h
+++ b/modules/mono/mono_gd/gd_mono.h
@@ -48,9 +48,9 @@ enum Type {
 };
 
 struct Version {
-	uint64_t godot_api_hash;
-	uint32_t bindings_version;
-	uint32_t cs_glue_version;
+	uint64_t godot_api_hash = 0;
+	uint32_t bindings_version = 0;
+	uint32_t cs_glue_version = 0;
 
 	bool operator==(const Version &p_other) const {
 		return godot_api_hash == p_other.godot_api_hash &&
@@ -58,11 +58,7 @@ struct Version {
 			   cs_glue_version == p_other.cs_glue_version;
 	}
 
-	Version() :
-			godot_api_hash(0),
-			bindings_version(0),
-			cs_glue_version(0) {
-	}
+	Version() {}
 
 	Version(uint64_t p_godot_api_hash,
 			uint32_t p_bindings_version,
@@ -87,13 +83,10 @@ public:
 	};
 
 	struct LoadedApiAssembly {
-		GDMonoAssembly *assembly;
-		bool out_of_sync;
+		GDMonoAssembly *assembly = nullptr;
+		bool out_of_sync = false;
 
-		LoadedApiAssembly() :
-				assembly(nullptr),
-				out_of_sync(false) {
-		}
+		LoadedApiAssembly() {}
 	};
 
 private:
diff --git a/modules/mono/mono_gd/gd_mono_assembly.cpp b/modules/mono/mono_gd/gd_mono_assembly.cpp
index da2ed2a7fc..ca84338666 100644
--- a/modules/mono/mono_gd/gd_mono_assembly.cpp
+++ b/modules/mono/mono_gd/gd_mono_assembly.cpp
@@ -490,18 +490,7 @@ GDMonoAssembly *GDMonoAssembly::load_from(const String &p_name, const String &p_
 	return loaded_asm;
 }
 
-GDMonoAssembly::GDMonoAssembly(const String &p_name, MonoImage *p_image, MonoAssembly *p_assembly) :
-		name(p_name),
-		image(p_image),
-		assembly(p_assembly),
-#ifdef GD_MONO_HOT_RELOAD
-		modified_time(0),
-#endif
-		gdobject_class_cache_updated(false) {
-}
-
 GDMonoAssembly::~GDMonoAssembly() {
-
 	if (image)
 		unload();
 }
diff --git a/modules/mono/mono_gd/gd_mono_assembly.h b/modules/mono/mono_gd/gd_mono_assembly.h
index 7fc1817993..cc8d699558 100644
--- a/modules/mono/mono_gd/gd_mono_assembly.h
+++ b/modules/mono/mono_gd/gd_mono_assembly.h
@@ -73,10 +73,10 @@ class GDMonoAssembly {
 	MonoAssembly *assembly;
 
 #ifdef GD_MONO_HOT_RELOAD
-	uint64_t modified_time;
+	uint64_t modified_time = 0;
 #endif
 
-	bool gdobject_class_cache_updated;
+	bool gdobject_class_cache_updated = false;
 	Map<StringName, GDMonoClass *> gdobject_class_cache;
 
 	HashMap<ClassKey, GDMonoClass *, ClassKey::Hasher> cached_classes;
@@ -125,7 +125,11 @@ public:
 	static GDMonoAssembly *load(const String &p_name, MonoAssemblyName *p_aname, bool p_refonly, const Vector<String> &p_search_dirs);
 	static GDMonoAssembly *load_from(const String &p_name, const String &p_path, bool p_refonly);
 
-	GDMonoAssembly(const String &p_name, MonoImage *p_image, MonoAssembly *p_assembly);
+	GDMonoAssembly(const String &p_name, MonoImage *p_image, MonoAssembly *p_assembly) :
+			name(p_name),
+			image(p_image),
+			assembly(p_assembly) {
+	}
 	~GDMonoAssembly();
 };
 
diff --git a/modules/mono/mono_gd/gd_mono_method_thunk.h b/modules/mono/mono_gd/gd_mono_method_thunk.h
index 0e05e974e9..82c6f32c81 100644
--- a/modules/mono/mono_gd/gd_mono_method_thunk.h
+++ b/modules/mono/mono_gd/gd_mono_method_thunk.h
@@ -50,7 +50,7 @@ struct GDMonoMethodThunk {
 
 	typedef void(GD_MONO_STDCALL *M)(ParamTypes... p_args, MonoException **);
 
-	M mono_method_thunk;
+	M mono_method_thunk = nullptr;
 
 public:
 	_FORCE_INLINE_ void invoke(ParamTypes... p_args, MonoException **r_exc) {
@@ -81,9 +81,7 @@ public:
 		mono_method_thunk = (M)mono_method_get_unmanaged_thunk(p_mono_method->get_mono_ptr());
 	}
 
-	GDMonoMethodThunk() :
-			mono_method_thunk(nullptr) {
-	}
+	GDMonoMethodThunk() {}
 
 	explicit GDMonoMethodThunk(GDMonoMethod *p_mono_method) {
 		set_from_method(p_mono_method);
@@ -95,7 +93,7 @@ struct GDMonoMethodThunkR {
 
 	typedef R(GD_MONO_STDCALL *M)(ParamTypes... p_args, MonoException **);
 
-	M mono_method_thunk;
+	M mono_method_thunk = nullptr;
 
 public:
 	_FORCE_INLINE_ R invoke(ParamTypes... p_args, MonoException **r_exc) {
@@ -127,9 +125,7 @@ public:
 		mono_method_thunk = (M)mono_method_get_unmanaged_thunk(p_mono_method->get_mono_ptr());
 	}
 
-	GDMonoMethodThunkR() :
-			mono_method_thunk(nullptr) {
-	}
+	GDMonoMethodThunkR() {}
 
 	explicit GDMonoMethodThunkR(GDMonoMethod *p_mono_method) {
 #ifdef DEBUG_ENABLED
@@ -248,7 +244,7 @@ struct VariadicInvokeMonoMethodR<1, R, P1> {
 template <class... ParamTypes>
 struct GDMonoMethodThunk {
 
-	GDMonoMethod *mono_method;
+	GDMonoMethod *mono_method = nullptr;
 
 public:
 	_FORCE_INLINE_ void invoke(ParamTypes... p_args, MonoException **r_exc) {
@@ -277,9 +273,7 @@ public:
 		mono_method = p_mono_method;
 	}
 
-	GDMonoMethodThunk() :
-			mono_method(nullptr) {
-	}
+	GDMonoMethodThunk() {}
 
 	explicit GDMonoMethodThunk(GDMonoMethod *p_mono_method) {
 		set_from_method(p_mono_method);
@@ -289,7 +283,7 @@ public:
 template <class R, class... ParamTypes>
 struct GDMonoMethodThunkR {
 
-	GDMonoMethod *mono_method;
+	GDMonoMethod *mono_method = nullptr;
 
 public:
 	_FORCE_INLINE_ R invoke(ParamTypes... p_args, MonoException **r_exc) {
@@ -318,9 +312,7 @@ public:
 		mono_method = p_mono_method;
 	}
 
-	GDMonoMethodThunkR() :
-			mono_method(nullptr) {
-	}
+	GDMonoMethodThunkR() {}
 
 	explicit GDMonoMethodThunkR(GDMonoMethod *p_mono_method) {
 		set_from_method(p_mono_method);
diff --git a/modules/mono/mono_gd/gd_mono_utils.cpp b/modules/mono/mono_gd/gd_mono_utils.cpp
index c0fea6ede9..a2ae42ae9f 100644
--- a/modules/mono/mono_gd/gd_mono_utils.cpp
+++ b/modules/mono/mono_gd/gd_mono_utils.cpp
@@ -664,8 +664,7 @@ GDMonoClass *make_generic_dictionary_type(MonoReflectionType *p_key_reftype, Mon
 
 } // namespace Marshal
 
-ScopeThreadAttach::ScopeThreadAttach() :
-		mono_thread(nullptr) {
+ScopeThreadAttach::ScopeThreadAttach() {
 	if (likely(GDMono::get_singleton()->is_runtime_initialized()) && unlikely(!mono_domain_get())) {
 		mono_thread = GDMonoUtils::attach_current_thread();
 	}
diff --git a/modules/mono/mono_gd/gd_mono_utils.h b/modules/mono/mono_gd/gd_mono_utils.h
index e3011ade5d..caf0c792b7 100644
--- a/modules/mono/mono_gd/gd_mono_utils.h
+++ b/modules/mono/mono_gd/gd_mono_utils.h
@@ -155,7 +155,7 @@ struct ScopeThreadAttach {
 	~ScopeThreadAttach();
 
 private:
-	MonoThread *mono_thread;
+	MonoThread *mono_thread = nullptr;
 };
 
 StringName get_native_godot_class_name(GDMonoClass *p_class);
diff --git a/modules/mono/mono_gd/managed_type.h b/modules/mono/mono_gd/managed_type.h
index 84d1837853..491a2f3d20 100644
--- a/modules/mono/mono_gd/managed_type.h
+++ b/modules/mono/mono_gd/managed_type.h
@@ -36,18 +36,15 @@
 #include "gd_mono_header.h"
 
 struct ManagedType {
-	int type_encoding;
-	GDMonoClass *type_class;
+	int type_encoding = 0;
+	GDMonoClass *type_class = nullptr;
 
 	static ManagedType from_class(GDMonoClass *p_class);
 	static ManagedType from_class(MonoClass *p_mono_class);
 	static ManagedType from_type(MonoType *p_mono_type);
 	static ManagedType from_reftype(MonoReflectionType *p_mono_reftype);
 
-	ManagedType() :
-			type_encoding(0),
-			type_class(nullptr) {
-	}
+	ManagedType() {}
 
 	ManagedType(int p_type_encoding, GDMonoClass *p_type_class) :
 			type_encoding(p_type_encoding),