5 files changed, 198 insertions, 139 deletions

diff --git a/modules/mono/editor/bindings_generator.cpp b/modules/mono/editor/bindings_generator.cpp
index bcf08026bc..710682d3aa 100644
--- a/modules/mono/editor/bindings_generator.cpp
+++ b/modules/mono/editor/bindings_generator.cpp
@@ -97,7 +97,7 @@
 #define C_METHOD_MONOARRAY_TO(m_type) C_NS_MONOMARSHAL "::mono_array_to_" #m_type
 #define C_METHOD_MONOARRAY_FROM(m_type) C_NS_MONOMARSHAL "::" #m_type "_to_mono_array"
 
-#define BINDINGS_GENERATOR_VERSION UINT32_C(3)
+#define BINDINGS_GENERATOR_VERSION UINT32_C(5)
 
 const char *BindingsGenerator::TypeInterface::DEFAULT_VARARG_C_IN = "\t%0 %1_in = %1;\n";
 
@@ -173,23 +173,74 @@ static String snake_to_camel_case(const String &p_identifier, bool p_input_is_up
 	return ret;
 }
 
-String BindingsGenerator::_determine_enum_prefix(const EnumInterface &p_ienum) {
+int BindingsGenerator::_determine_enum_prefix(const EnumInterface &p_ienum) {
 
 	CRASH_COND(p_ienum.constants.empty());
 
-	const List<ConstantInterface>::Element *front = p_ienum.constants.front();
-	int candidate_len = front->get().name.length();
+	const ConstantInterface &front_iconstant = p_ienum.constants.front()->get();
+	Vector<String> front_parts = front_iconstant.name.split("_", /* p_allow_empty: */ true);
+	int candidate_len = front_parts.size() - 1;
 
-	for (const List<ConstantInterface>::Element *E = front->next(); E; E = E->next()) {
-		int j = 0;
-		for (j = 0; j < candidate_len && j < E->get().name.length(); j++) {
-			if (front->get().name[j] != E->get().name[j])
-				break;
+	if (candidate_len == 0)
+		return 0;
+
+	for (const List<ConstantInterface>::Element *E = p_ienum.constants.front()->next(); E; E = E->next()) {
+		const ConstantInterface &iconstant = E->get();
+
+		Vector<String> parts = iconstant.name.split("_", /* p_allow_empty: */ true);
+
+		int i;
+		for (i = 0; i < candidate_len && i < parts.size(); i++) {
+			if (front_parts[i] != parts[i]) {
+				// HARDCODED: Some Flag enums have the prefix 'FLAG_' for everything except 'FLAGS_DEFAULT' (same for 'METHOD_FLAG_' and'METHOD_FLAGS_DEFAULT').
+				bool hardcoded_exc = (i == candidate_len - 1 && ((front_parts[i] == "FLAGS" && parts[i] == "FLAG") || (front_parts[i] == "FLAG" && parts[i] == "FLAGS")));
+				if (!hardcoded_exc)
+					break;
+			}
 		}
-		candidate_len = j;
+		candidate_len = i;
+
+		if (candidate_len == 0)
+			return 0;
 	}
 
-	return front->get().name.substr(0, candidate_len);
+	return candidate_len;
+}
+
+void BindingsGenerator::_apply_prefix_to_enum_constants(BindingsGenerator::EnumInterface &p_ienum, int p_prefix_length) {
+
+	if (p_prefix_length > 0) {
+		for (List<ConstantInterface>::Element *E = p_ienum.constants.front(); E; E = E->next()) {
+			int curr_prefix_length = p_prefix_length;
+
+			ConstantInterface &curr_const = E->get();
+
+			String constant_name = curr_const.name;
+
+			Vector<String> parts = constant_name.split("_", /* p_allow_empty: */ true);
+
+			if (parts.size() <= curr_prefix_length)
+				continue;
+
+			if (parts[curr_prefix_length][0] >= '0' && parts[curr_prefix_length][0] <= '9') {
+				// The name of enum constants may begin with a numeric digit when strip from the enum prefix,
+				// so we make the prefix for this constant one word shorter in those cases.
+				for (curr_prefix_length = curr_prefix_length - 1; curr_prefix_length > 0; curr_prefix_length--) {
+					if (parts[curr_prefix_length][0] < '0' || parts[curr_prefix_length][0] > '9')
+						break;
+				}
+			}
+
+			constant_name = "";
+			for (int i = curr_prefix_length; i < parts.size(); i++) {
+				if (i > curr_prefix_length)
+					constant_name += "_";
+				constant_name += parts[i];
+			}
+
+			curr_const.proxy_name = snake_to_pascal_case(constant_name, true);
+		}
+	}
 }
 
 void BindingsGenerator::_generate_method_icalls(const TypeInterface &p_itype) {
@@ -272,7 +323,7 @@ void BindingsGenerator::_generate_global_constants(List<String> &p_output) {
 		}
 
 		p_output.push_back(MEMBER_BEGIN "public const int ");
-		p_output.push_back(iconstant.name);
+		p_output.push_back(iconstant.proxy_name);
 		p_output.push_back(" = ");
 		p_output.push_back(itos(iconstant.value));
 		p_output.push_back(";");
@@ -334,25 +385,8 @@ void BindingsGenerator::_generate_global_constants(List<String> &p_output) {
 				p_output.push_back(INDENT2 "/// </summary>\n");
 			}
 
-			String constant_name = iconstant.name;
-
-			if (!ienum.prefix.empty() && constant_name.begins_with(ienum.prefix)) {
-				constant_name = constant_name.substr(ienum.prefix.length(), constant_name.length());
-			}
-
-			if (constant_name[0] >= '0' && constant_name[0] <= '9') {
-				// The name of enum constants may begin with a numeric digit when strip from the enum prefix,
-				// so we make the prefix one word shorter in those cases.
-				int i = 0;
-				for (i = ienum.prefix.length() - 1; i >= 0; i--) {
-					if (ienum.prefix[i] >= 'A' && ienum.prefix[i] <= 'Z')
-						break;
-				}
-				constant_name = ienum.prefix.substr(i, ienum.prefix.length()) + constant_name;
-			}
-
 			p_output.push_back(INDENT2);
-			p_output.push_back(constant_name);
+			p_output.push_back(iconstant.proxy_name);
 			p_output.push_back(" = ");
 			p_output.push_back(itos(iconstant.value));
 			p_output.push_back(E != ienum.constants.back() ? ",\n" : "\n");
@@ -646,8 +680,11 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 	List<String> output;
 
 	output.push_back("using System;\n"); // IntPtr
+	output.push_back("using System.Diagnostics;\n"); // DebuggerBrowsable
+
 	output.push_back("\n#pragma warning disable CS1591 // Disable warning: "
 					 "'Missing XML comment for publicly visible type or member'\n");
+
 	output.push_back("\nnamespace " BINDINGS_NAMESPACE "\n" OPEN_BLOCK);
 
 	const DocData::ClassDoc *class_doc = itype.class_doc;
@@ -717,7 +754,7 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 			}
 
 			output.push_back(MEMBER_BEGIN "public const int ");
-			output.push_back(iconstant.name);
+			output.push_back(iconstant.proxy_name);
 			output.push_back(" = ");
 			output.push_back(itos(iconstant.value));
 			output.push_back(";");
@@ -757,25 +794,8 @@ Error BindingsGenerator::_generate_cs_type(const TypeInterface &itype, const Str
 					output.push_back(INDENT3 "/// </summary>\n");
 				}
 
-				String constant_name = iconstant.name;
-
-				if (!ienum.prefix.empty() && constant_name.begins_with(ienum.prefix)) {
-					constant_name = constant_name.substr(ienum.prefix.length(), constant_name.length());
-				}
-
-				if (constant_name[0] >= '0' && constant_name[0] <= '9') {
-					// The name of enum constants may begin with a numeric digit when strip from the enum prefix,
-					// so we make the prefix one word shorter in those cases.
-					int i = 0;
-					for (i = ienum.prefix.length() - 1; i >= 0; i--) {
-						if (ienum.prefix[i] >= 'A' && ienum.prefix[i] <= 'Z')
-							break;
-					}
-					constant_name = ienum.prefix.substr(i, ienum.prefix.length()) + constant_name;
-				}
-
 				output.push_back(INDENT3);
-				output.push_back(constant_name);
+				output.push_back(iconstant.proxy_name);
 				output.push_back(" = ");
 				output.push_back(itos(iconstant.value));
 				output.push_back(E != ienum.constants.back() ? ",\n" : "\n");
@@ -1086,7 +1106,7 @@ Error BindingsGenerator::_generate_cs_method(const BindingsGenerator::TypeInterf
 	// Generate method
 	{
 		if (!p_imethod.is_virtual && !p_imethod.requires_object_call) {
-			p_output.push_back(MEMBER_BEGIN "private static IntPtr ");
+			p_output.push_back(MEMBER_BEGIN "[DebuggerBrowsable(DebuggerBrowsableState.Never)]" MEMBER_BEGIN "private static IntPtr ");
 			p_output.push_back(method_bind_field + " = Object." ICALL_GET_METHODBIND "(" BINDINGS_NATIVE_NAME_FIELD ", \"");
 			p_output.push_back(p_imethod.name);
 			p_output.push_back("\");\n");
@@ -1843,11 +1863,13 @@ void BindingsGenerator::_populate_object_type_interfaces() {
 			EnumInterface ienum(enum_proxy_cname);
 			const List<StringName> &constants = enum_map.get(*k);
 			for (const List<StringName>::Element *E = constants.front(); E; E = E->next()) {
-				int *value = class_info->constant_map.getptr(E->get());
+				const StringName &constant_cname = E->get();
+				String constant_name = constant_cname.operator String();
+				int *value = class_info->constant_map.getptr(constant_cname);
 				ERR_FAIL_NULL(value);
-				constant_list.erase(E->get().operator String());
+				constant_list.erase(constant_name);
 
-				ConstantInterface iconstant(snake_to_pascal_case(E->get(), true), *value);
+				ConstantInterface iconstant(constant_name, snake_to_pascal_case(constant_name, true), *value);
 
 				iconstant.const_doc = NULL;
 				for (int i = 0; i < itype.class_doc->constants.size(); i++) {
@@ -1862,7 +1884,9 @@ void BindingsGenerator::_populate_object_type_interfaces() {
 				ienum.constants.push_back(iconstant);
 			}
 
-			ienum.prefix = _determine_enum_prefix(ienum);
+			int prefix_length = _determine_enum_prefix(ienum);
+
+			_apply_prefix_to_enum_constants(ienum, prefix_length);
 
 			itype.enums.push_back(ienum);
 
@@ -1876,10 +1900,11 @@ void BindingsGenerator::_populate_object_type_interfaces() {
 		}
 
 		for (const List<String>::Element *E = constant_list.front(); E; E = E->next()) {
-			int *value = class_info->constant_map.getptr(E->get());
+			const String &constant_name = E->get();
+			int *value = class_info->constant_map.getptr(StringName(E->get()));
 			ERR_FAIL_NULL(value);
 
-			ConstantInterface iconstant(snake_to_pascal_case(E->get(), true), *value);
+			ConstantInterface iconstant(constant_name, snake_to_pascal_case(constant_name, true), *value);
 
 			iconstant.const_doc = NULL;
 			for (int i = 0; i < itype.class_doc->constants.size(); i++) {
@@ -1990,18 +2015,18 @@ void BindingsGenerator::_populate_builtin_type_interfaces() {
 
 	TypeInterface itype;
 
-#define INSERT_STRUCT_TYPE(m_type, m_type_in)                                                         \
-	{                                                                                                 \
-		itype = TypeInterface::create_value_type(String(#m_type));                                    \
-		itype.c_in = "\tMARSHALLED_IN(" #m_type ", %1, %1_in);\n";                                    \
-		itype.c_out = "\tMARSHALLED_OUT(" #m_type ", %1, ret_out)\n"                                  \
-					  "\treturn mono_value_box(mono_domain_get(), CACHED_CLASS_RAW(%2), ret_out);\n"; \
-		itype.c_arg_in = "&%s_in";                                                                    \
-		itype.c_type_in = m_type_in;                                                                  \
-		itype.cs_in = "ref %s";                                                                       \
-		itype.cs_out = "return (%1)%0;";                                                              \
-		itype.im_type_out = "object";                                                                 \
-		builtin_types.insert(itype.cname, itype);                                                     \
+#define INSERT_STRUCT_TYPE(m_type, m_type_in)                          \
+	{                                                                  \
+		itype = TypeInterface::create_value_type(String(#m_type));     \
+		itype.c_in = "\t%0 %1_in = MARSHALLED_IN(" #m_type ", %1);\n"; \
+		itype.c_out = "\treturn MARSHALLED_OUT(" #m_type ", %1);\n";   \
+		itype.c_arg_in = "&%s_in";                                     \
+		itype.c_type_in = "GDMonoMarshal::M_" #m_type "*";             \
+		itype.c_type_out = "GDMonoMarshal::M_" #m_type;                \
+		itype.cs_in = "ref %s";                                        \
+		itype.cs_out = "return (%1)%0;";                               \
+		itype.im_type_out = itype.cs_type;                             \
+		builtin_types.insert(itype.cname, itype);                      \
 	}
 
 	INSERT_STRUCT_TYPE(Vector2, "real_t*")
@@ -2019,26 +2044,31 @@ void BindingsGenerator::_populate_builtin_type_interfaces() {
 
 	// bool
 	itype = TypeInterface::create_value_type(String("bool"));
-	itype.c_arg_in = "&%s_in";
-	// /* MonoBoolean <---> bool
-	itype.c_in = "\t%0 %1_in = (%0)%1;\n";
-	itype.c_out = "\treturn (%0)%1;\n";
-	itype.c_type = "bool";
-	// */
-	itype.c_type_in = "MonoBoolean";
-	itype.c_type_out = itype.c_type_in;
+
+	{
+		// MonoBoolean <---> bool
+		itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+		itype.c_out = "\treturn (%0)%1;\n";
+		itype.c_type = "bool";
+		itype.c_type_in = "MonoBoolean";
+		itype.c_type_out = itype.c_type_in;
+		itype.c_arg_in = "&%s_in";
+	}
 	itype.im_type_in = itype.name;
 	itype.im_type_out = itype.name;
 	builtin_types.insert(itype.cname, itype);
 
 	// int
+	// C interface is the same as that of enums. Remember to apply any
+	// changes done here to TypeInterface::postsetup_enum_type as well
 	itype = TypeInterface::create_value_type(String("int"));
 	itype.c_arg_in = "&%s_in";
-	// /* ptrcall only supports int64_t and uint64_t
-	itype.c_in = "\t%0 %1_in = (%0)%1;\n";
-	itype.c_out = "\treturn (%0)%1;\n";
-	itype.c_type = "int64_t";
-	// */
+	{
+		// The expected types for parameters and return value in ptrcall are 'int64_t' or 'uint64_t'.
+		itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+		itype.c_out = "\treturn (%0)%1;\n";
+		itype.c_type = "int64_t";
+	}
 	itype.c_type_in = "int32_t";
 	itype.c_type_out = itype.c_type_in;
 	itype.im_type_in = itype.name;
@@ -2047,21 +2077,22 @@ void BindingsGenerator::_populate_builtin_type_interfaces() {
 
 	// real_t
 	itype = TypeInterface();
+	itype.name = "float"; // The name is always "float" in Variant, even with REAL_T_IS_DOUBLE.
+	itype.cname = itype.name;
 #ifdef REAL_T_IS_DOUBLE
-	itype.name = "double";
+	itype.proxy_name = "double";
 #else
-	itype.name = "float";
+	itype.proxy_name = "float";
 #endif
-	itype.cname = itype.name;
-	itype.proxy_name = itype.name;
-	itype.c_arg_in = "&%s_in";
-	//* ptrcall only supports double
-	itype.c_in = "\t%0 %1_in = (%0)%1;\n";
-	itype.c_out = "\treturn (%0)%1;\n";
-	itype.c_type = "double";
-	//*/
-	itype.c_type_in = "real_t";
-	itype.c_type_out = "real_t";
+	{
+		// The expected type for parameters and return value in ptrcall is 'double'.
+		itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+		itype.c_out = "\treturn (%0)%1;\n";
+		itype.c_type = "double";
+		itype.c_type_in = "real_t";
+		itype.c_type_out = "real_t";
+		itype.c_arg_in = "&%s_in";
+	}
 	itype.cs_type = itype.proxy_name;
 	itype.im_type_in = itype.proxy_name;
 	itype.im_type_out = itype.proxy_name;
@@ -2256,7 +2287,7 @@ void BindingsGenerator::_populate_global_constants() {
 			int constant_value = GlobalConstants::get_global_constant_value(i);
 			StringName enum_name = GlobalConstants::get_global_constant_enum(i);
 
-			ConstantInterface iconstant(snake_to_pascal_case(constant_name, true), constant_value);
+			ConstantInterface iconstant(constant_name, snake_to_pascal_case(constant_name, true), constant_value);
 			iconstant.const_doc = const_doc;
 
 			if (enum_name != StringName()) {
@@ -2284,16 +2315,18 @@ void BindingsGenerator::_populate_global_constants() {
 			TypeInterface::postsetup_enum_type(enum_itype);
 			enum_types.insert(enum_itype.cname, enum_itype);
 
-			ienum.prefix = _determine_enum_prefix(ienum);
+			int prefix_length = _determine_enum_prefix(ienum);
 
-			// HARDCODED
+			// HARDCODED: The Error enum have the prefix 'ERR_' for everything except 'OK' and 'FAILED'.
 			if (ienum.cname == name_cache.enum_Error) {
-				if (!ienum.prefix.empty()) { // Just in case it ever changes
+				if (prefix_length > 0) { // Just in case it ever changes
 					ERR_PRINTS("Prefix for enum 'Error' is not empty");
 				}
 
-				ienum.prefix = "Err";
+				prefix_length = 1; // 'ERR_'
 			}
+
+			_apply_prefix_to_enum_constants(ienum, prefix_length);
 		}
 	}
 
diff --git a/modules/mono/editor/bindings_generator.h b/modules/mono/editor/bindings_generator.h
index ad89255ba5..38cf99c294 100644
--- a/modules/mono/editor/bindings_generator.h
+++ b/modules/mono/editor/bindings_generator.h
@@ -43,20 +43,21 @@ class BindingsGenerator {
 
 	struct ConstantInterface {
 		String name;
+		String proxy_name;
 		int value;
 		const DocData::ConstantDoc *const_doc;
 
 		ConstantInterface() {}
 
-		ConstantInterface(const String &p_name, int p_value) {
+		ConstantInterface(const String &p_name, const String &p_proxy_name, int p_value) {
 			name = p_name;
+			proxy_name = p_proxy_name;
 			value = p_value;
 		}
 	};
 
 	struct EnumInterface {
 		StringName cname;
-		String prefix;
 		List<ConstantInterface> constants;
 
 		_FORCE_INLINE_ bool operator==(const EnumInterface &p_ienum) const {
@@ -223,7 +224,7 @@ class BindingsGenerator {
 		String c_in;
 
 		/**
-		 * Determines the name of the variable that will be passed as argument to a ptrcall.
+		 * Determines the expression that will be passed as argument to ptrcall.
 		 * By default the value equals the name of the parameter,
 		 * this varies for types that require special manipulation via [c_in].
 		 * Formatting elements:
@@ -333,8 +334,6 @@ class BindingsGenerator {
 			itype.proxy_name = itype.name;
 
 			itype.c_type = itype.name;
-			itype.c_type_in = "void*";
-			itype.c_type_out = "MonoObject*";
 			itype.cs_type = itype.proxy_name;
 			itype.im_type_in = "ref " + itype.proxy_name;
 			itype.im_type_out = itype.proxy_name;
@@ -385,10 +384,19 @@ class BindingsGenerator {
 		}
 
 		static void postsetup_enum_type(TypeInterface &r_enum_itype) {
-			r_enum_itype.c_arg_in = "&%s";
-			r_enum_itype.c_type = "int";
-			r_enum_itype.c_type_in = "int";
-			r_enum_itype.c_type_out = "int";
+			// C interface is the same as that of 'int'. Remember to apply any
+			// changes done here to the 'int' type interface as well
+
+			r_enum_itype.c_arg_in = "&%s_in";
+			{
+				// The expected types for parameters and return value in ptrcall are 'int64_t' or 'uint64_t'.
+				r_enum_itype.c_in = "\t%0 %1_in = (%0)%1;\n";
+				r_enum_itype.c_out = "\treturn (%0)%1;\n";
+				r_enum_itype.c_type = "int64_t";
+			}
+			r_enum_itype.c_type_in = "int32_t";
+			r_enum_itype.c_type_out = r_enum_itype.c_type_in;
+
 			r_enum_itype.cs_type = r_enum_itype.proxy_name;
 			r_enum_itype.cs_in = "(int)%s";
 			r_enum_itype.cs_out = "return (%1)%0;";
@@ -513,7 +521,8 @@ class BindingsGenerator {
 		return p_type.name;
 	}
 
-	String _determine_enum_prefix(const EnumInterface &p_ienum);
+	int _determine_enum_prefix(const EnumInterface &p_ienum);
+	void _apply_prefix_to_enum_constants(EnumInterface &p_ienum, int p_prefix_length);
 
 	void _generate_method_icalls(const TypeInterface &p_itype);
 
diff --git a/modules/mono/editor/godotsharp_builds.cpp b/modules/mono/editor/godotsharp_builds.cpp
index 8fe6e46b60..b504cfe712 100644
--- a/modules/mono/editor/godotsharp_builds.cpp
+++ b/modules/mono/editor/godotsharp_builds.cpp
@@ -306,6 +306,16 @@ String GodotSharpBuilds::_api_folder_name(APIAssembly::Type p_api_type) {
 bool GodotSharpBuilds::make_api_sln(APIAssembly::Type p_api_type) {
 
 	String api_name = p_api_type == APIAssembly::API_CORE ? API_ASSEMBLY_NAME : EDITOR_API_ASSEMBLY_NAME;
+
+	String editor_prebuilt_api_dir = GodotSharpDirs::get_data_editor_prebuilt_api_dir();
+	String res_assemblies_dir = GodotSharpDirs::get_res_assemblies_dir();
+
+	if (FileAccess::exists(editor_prebuilt_api_dir.plus_file(api_name + ".dll"))) {
+		EditorProgress pr("mono_copy_prebuilt_api_assembly", "Copying prebuilt " + api_name + " assembly...", 1);
+		pr.step("Copying " + api_name + " assembly", 0);
+		return GodotSharpBuilds::copy_api_assembly(editor_prebuilt_api_dir, res_assemblies_dir, api_name, p_api_type);
+	}
+
 	String api_build_config = "Release";
 
 	EditorProgress pr("mono_build_release_" + api_name, "Building " + api_name + " solution...", 3);
@@ -357,7 +367,6 @@ bool GodotSharpBuilds::make_api_sln(APIAssembly::Type p_api_type) {
 
 	// Copy the built assembly to the assemblies directory
 	String api_assembly_dir = api_sln_dir.plus_file("bin").plus_file(api_build_config);
-	String res_assemblies_dir = GodotSharpDirs::get_res_assemblies_dir();
 	if (!GodotSharpBuilds::copy_api_assembly(api_assembly_dir, res_assemblies_dir, api_name, p_api_type))
 		return false;
 
@@ -369,36 +378,11 @@ bool GodotSharpBuilds::build_project_blocking(const String &p_config) {
 	if (!FileAccess::exists(GodotSharpDirs::get_project_sln_path()))
 		return true; // No solution to build
 
-	String editor_prebuilt_api_dir = GodotSharpDirs::get_data_editor_prebuilt_api_dir();
-	String res_assemblies_dir = GodotSharpDirs::get_res_assemblies_dir();
-
-	if (FileAccess::exists(editor_prebuilt_api_dir.plus_file(API_ASSEMBLY_NAME ".dll"))) {
-		EditorProgress pr("mono_copy_prebuilt_api_assemblies",
-				"Copying prebuilt " API_ASSEMBLY_NAME " assemblies...", 1);
-		pr.step("Copying " API_ASSEMBLY_NAME " assembly", 0);
-
-		if (!GodotSharpBuilds::copy_api_assembly(editor_prebuilt_api_dir, res_assemblies_dir,
-					API_ASSEMBLY_NAME, APIAssembly::API_CORE)) {
-			return false;
-		}
-	} else {
-		if (!GodotSharpBuilds::make_api_sln(APIAssembly::API_CORE))
-			return false;
-	}
-
-	if (DirAccess::exists(editor_prebuilt_api_dir.plus_file(EDITOR_API_ASSEMBLY_NAME ".dll"))) {
-		EditorProgress pr("mono_copy_prebuilt_api_assemblies",
-				"Copying prebuilt " EDITOR_API_ASSEMBLY_NAME " assemblies...", 1);
-		pr.step("Copying " EDITOR_API_ASSEMBLY_NAME " assembly", 0);
+	if (!GodotSharpBuilds::make_api_sln(APIAssembly::API_CORE))
+		return false;
 
-		if (!GodotSharpBuilds::copy_api_assembly(editor_prebuilt_api_dir, res_assemblies_dir,
-					EDITOR_API_ASSEMBLY_NAME, APIAssembly::API_EDITOR)) {
-			return false;
-		}
-	} else {
-		if (!GodotSharpBuilds::make_api_sln(APIAssembly::API_EDITOR))
-			return false;
-	}
+	if (!GodotSharpBuilds::make_api_sln(APIAssembly::API_EDITOR))
+		return false;
 
 	EditorProgress pr("mono_project_debug_build", "Building project solution...", 1);
 	pr.step("Building project solution", 0);
diff --git a/modules/mono/editor/godotsharp_editor.cpp b/modules/mono/editor/godotsharp_editor.cpp
index fca88a7164..9df4e10266 100644
--- a/modules/mono/editor/godotsharp_editor.cpp
+++ b/modules/mono/editor/godotsharp_editor.cpp
@@ -108,6 +108,33 @@ bool GodotSharpEditor::_create_project_solution() {
 	return true;
 }
 
+void GodotSharpEditor::_make_api_solutions_if_needed() {
+	// I'm sick entirely of ProgressDialog
+	static bool recursion_guard = false;
+	if (!recursion_guard) {
+		recursion_guard = true;
+		_make_api_solutions_if_needed_impl();
+		recursion_guard = false;
+	}
+}
+
+void GodotSharpEditor::_make_api_solutions_if_needed_impl() {
+	// If the project has a solution and C# project make sure the API assemblies are present and up to date
+	String res_assemblies_dir = GodotSharpDirs::get_res_assemblies_dir();
+
+	if (!FileAccess::exists(res_assemblies_dir.plus_file(API_ASSEMBLY_NAME ".dll")) ||
+			GDMono::get_singleton()->metadata_is_api_assembly_invalidated(APIAssembly::API_CORE)) {
+		if (!GodotSharpBuilds::make_api_sln(APIAssembly::API_CORE))
+			return;
+	}
+
+	if (!FileAccess::exists(res_assemblies_dir.plus_file(EDITOR_API_ASSEMBLY_NAME ".dll")) ||
+			GDMono::get_singleton()->metadata_is_api_assembly_invalidated(APIAssembly::API_EDITOR)) {
+		if (!GodotSharpBuilds::make_api_sln(APIAssembly::API_EDITOR))
+			return; // Redundant? I don't think so
+	}
+}
+
 void GodotSharpEditor::_remove_create_sln_menu_option() {
 
 	menu_popup->remove_item(menu_popup->get_item_index(MENU_CREATE_SLN));
@@ -169,6 +196,7 @@ void GodotSharpEditor::_notification(int p_notification) {
 void GodotSharpEditor::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("_create_project_solution"), &GodotSharpEditor::_create_project_solution);
+	ClassDB::bind_method(D_METHOD("_make_api_solutions_if_needed"), &GodotSharpEditor::_make_api_solutions_if_needed);
 	ClassDB::bind_method(D_METHOD("_remove_create_sln_menu_option"), &GodotSharpEditor::_remove_create_sln_menu_option);
 	ClassDB::bind_method(D_METHOD("_toggle_about_dialog_on_start"), &GodotSharpEditor::_toggle_about_dialog_on_start);
 	ClassDB::bind_method(D_METHOD("_menu_option_pressed", "id"), &GodotSharpEditor::_menu_option_pressed);
@@ -390,7 +418,10 @@ GodotSharpEditor::GodotSharpEditor(EditorNode *p_editor) {
 	String sln_path = GodotSharpDirs::get_project_sln_path();
 	String csproj_path = GodotSharpDirs::get_project_csproj_path();
 
-	if (!FileAccess::exists(sln_path) || !FileAccess::exists(csproj_path)) {
+	if (FileAccess::exists(sln_path) && FileAccess::exists(csproj_path)) {
+		// We can't use EditorProgress here. It calls Main::iterarion() and the main loop is not initialized yet.
+		call_deferred("_make_api_solutions_if_needed");
+	} else {
 		bottom_panel_btn->hide();
 		menu_popup->add_item(TTR("Create C# solution"), MENU_CREATE_SLN);
 	}
diff --git a/modules/mono/editor/godotsharp_editor.h b/modules/mono/editor/godotsharp_editor.h
index 46b6bd5ebf..9fb0e40132 100644
--- a/modules/mono/editor/godotsharp_editor.h
+++ b/modules/mono/editor/godotsharp_editor.h
@@ -56,6 +56,8 @@ class GodotSharpEditor : public Node {
 #endif
 
 	bool _create_project_solution();
+	void _make_api_solutions_if_needed();
+	void _make_api_solutions_if_needed_impl();
 
 	void _remove_create_sln_menu_option();
 	void _show_about_dialog();