Merge pull request #79880 from dalexeev/gds-fix-id-shadowing-below

GDScript: Fix bug with identifier shadowed below in current scope

18 files changed, 354 insertions, 206 deletions

diff --git a/modules/gdscript/gdscript_analyzer.cpp b/modules/gdscript/gdscript_analyzer.cpp
index 01e94ebb22..cb04913620 100644
--- a/modules/gdscript/gdscript_analyzer.cpp
+++ b/modules/gdscript/gdscript_analyzer.cpp
@@ -1772,6 +1772,15 @@ void GDScriptAnalyzer::resolve_assignable(GDScriptParser::AssignableNode *p_assi
 
 	bool is_constant = p_assignable->type == GDScriptParser::Node::CONSTANT;
 
+#ifdef DEBUG_ENABLED
+	if (p_assignable->identifier != nullptr && p_assignable->identifier->suite != nullptr && p_assignable->identifier->suite->parent_block != nullptr) {
+		if (p_assignable->identifier->suite->parent_block->has_local(p_assignable->identifier->name)) {
+			const GDScriptParser::SuiteNode::Local &local = p_assignable->identifier->suite->parent_block->get_local(p_assignable->identifier->name);
+			parser->push_warning(p_assignable->identifier, GDScriptWarning::CONFUSABLE_LOCAL_DECLARATION, local.get_name(), p_assignable->identifier->name);
+		}
+	}
+#endif
+
 	GDScriptParser::DataType specified_type;
 	bool has_specified_type = p_assignable->datatype_specifier != nullptr;
 	if (has_specified_type) {
@@ -3518,12 +3527,14 @@ void GDScriptAnalyzer::reduce_identifier_from_base(GDScriptParser::IdentifierNod
 				case GDScriptParser::ClassNode::Member::FUNCTION: {
 					if (is_base && (!base.is_meta_type || member.function->is_static)) {
 						p_identifier->set_datatype(make_callable_type(member.function->info));
+						p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_FUNCTION;
 						return;
 					}
 				} break;
 
 				case GDScriptParser::ClassNode::Member::CLASS: {
 					reduce_identifier_from_base_set_class(p_identifier, member.get_datatype());
+					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CLASS;
 					return;
 				}
 
@@ -3662,9 +3673,17 @@ void GDScriptAnalyzer::reduce_identifier(GDScriptParser::IdentifierNode *p_ident
 			found_source = true;
 		} break;
 		case GDScriptParser::IdentifierNode::UNDEFINED_SOURCE:
+		case GDScriptParser::IdentifierNode::MEMBER_FUNCTION:
+		case GDScriptParser::IdentifierNode::MEMBER_CLASS:
 			break;
 	}
 
+#ifdef DEBUG_ENABLED
+	if (!found_source && p_identifier->suite != nullptr && p_identifier->suite->has_local(p_identifier->name)) {
+		parser->push_warning(p_identifier, GDScriptWarning::CONFUSABLE_LOCAL_USAGE, p_identifier->name);
+	}
+#endif
+
 	// Not a local, so check members.
 	if (!found_source) {
 		reduce_identifier_from_base(p_identifier);
diff --git a/modules/gdscript/gdscript_compiler.cpp b/modules/gdscript/gdscript_compiler.cpp
index 745ccbb1ed..2a52db4158 100644
--- a/modules/gdscript/gdscript_compiler.cpp
+++ b/modules/gdscript/gdscript_compiler.cpp
@@ -225,194 +225,211 @@ GDScriptCodeGenerator::Address GDScriptCompiler::_parse_expression(CodeGen &code
 
 			StringName identifier = in->name;
 
-			// Try function parameters.
-			if (codegen.parameters.has(identifier)) {
-				return codegen.parameters[identifier];
-			}
-
-			// Try local variables and constants.
-			if (!p_initializer && codegen.locals.has(identifier)) {
-				return codegen.locals[identifier];
-			}
+			switch (in->source) {
+				// LOCALS.
+				case GDScriptParser::IdentifierNode::FUNCTION_PARAMETER:
+				case GDScriptParser::IdentifierNode::LOCAL_VARIABLE:
+				case GDScriptParser::IdentifierNode::LOCAL_CONSTANT:
+				case GDScriptParser::IdentifierNode::LOCAL_ITERATOR:
+				case GDScriptParser::IdentifierNode::LOCAL_BIND: {
+					// Try function parameters.
+					if (codegen.parameters.has(identifier)) {
+						return codegen.parameters[identifier];
+					}
 
-			// Try class members.
-			if (_is_class_member_property(codegen, identifier)) {
-				// Get property.
-				GDScriptCodeGenerator::Address temp = codegen.add_temporary(_gdtype_from_datatype(p_expression->get_datatype(), codegen.script));
-				gen->write_get_member(temp, identifier);
-				return temp;
-			}
+					// Try local variables and constants.
+					if (!p_initializer && codegen.locals.has(identifier)) {
+						return codegen.locals[identifier];
+					}
+				} break;
 
-			// Try members.
-			if (!codegen.function_node || !codegen.function_node->is_static) {
-				// Try member variables.
-				if (codegen.script->member_indices.has(identifier)) {
-					if (codegen.script->member_indices[identifier].getter != StringName() && codegen.script->member_indices[identifier].getter != codegen.function_name) {
-						// Perform getter.
-						GDScriptCodeGenerator::Address temp = codegen.add_temporary(codegen.script->member_indices[identifier].data_type);
-						Vector<GDScriptCodeGenerator::Address> args; // No argument needed.
-						gen->write_call_self(temp, codegen.script->member_indices[identifier].getter, args);
+				// MEMBERS.
+				case GDScriptParser::IdentifierNode::MEMBER_VARIABLE:
+				case GDScriptParser::IdentifierNode::INHERITED_VARIABLE: {
+					// Try class members.
+					if (_is_class_member_property(codegen, identifier)) {
+						// Get property.
+						GDScriptCodeGenerator::Address temp = codegen.add_temporary(_gdtype_from_datatype(p_expression->get_datatype(), codegen.script));
+						gen->write_get_member(temp, identifier);
 						return temp;
-					} else {
-						// No getter or inside getter: direct member access.
-						int idx = codegen.script->member_indices[identifier].index;
-						return GDScriptCodeGenerator::Address(GDScriptCodeGenerator::Address::MEMBER, idx, codegen.script->get_member_type(identifier));
 					}
-				}
-			}
 
-			// Try static variables.
-			{
-				GDScript *scr = codegen.script;
-				while (scr) {
-					if (scr->static_variables_indices.has(identifier)) {
-						if (scr->static_variables_indices[identifier].getter != StringName() && scr->static_variables_indices[identifier].getter != codegen.function_name) {
-							// Perform getter.
-							GDScriptCodeGenerator::Address temp = codegen.add_temporary(scr->static_variables_indices[identifier].data_type);
-							GDScriptCodeGenerator::Address class_addr(GDScriptCodeGenerator::Address::CLASS);
-							Vector<GDScriptCodeGenerator::Address> args; // No argument needed.
-							gen->write_call(temp, class_addr, scr->static_variables_indices[identifier].getter, args);
-							return temp;
-						} else {
-							// No getter or inside getter: direct variable access.
-							GDScriptCodeGenerator::Address temp = codegen.add_temporary(scr->static_variables_indices[identifier].data_type);
-							GDScriptCodeGenerator::Address _class = codegen.add_constant(scr);
-							int index = scr->static_variables_indices[identifier].index;
-							gen->write_get_static_variable(temp, _class, index);
-							return temp;
+					// Try members.
+					if (!codegen.function_node || !codegen.function_node->is_static) {
+						// Try member variables.
+						if (codegen.script->member_indices.has(identifier)) {
+							if (codegen.script->member_indices[identifier].getter != StringName() && codegen.script->member_indices[identifier].getter != codegen.function_name) {
+								// Perform getter.
+								GDScriptCodeGenerator::Address temp = codegen.add_temporary(codegen.script->member_indices[identifier].data_type);
+								Vector<GDScriptCodeGenerator::Address> args; // No argument needed.
+								gen->write_call_self(temp, codegen.script->member_indices[identifier].getter, args);
+								return temp;
+							} else {
+								// No getter or inside getter: direct member access.
+								int idx = codegen.script->member_indices[identifier].index;
+								return GDScriptCodeGenerator::Address(GDScriptCodeGenerator::Address::MEMBER, idx, codegen.script->get_member_type(identifier));
+							}
 						}
 					}
-					scr = scr->_base;
-				}
-			}
+				} break;
+				case GDScriptParser::IdentifierNode::MEMBER_FUNCTION:
+				case GDScriptParser::IdentifierNode::MEMBER_SIGNAL: {
+					// Try methods and signals (can be Callable and Signal).
+
+					// Search upwards through parent classes:
+					const GDScriptParser::ClassNode *base_class = codegen.class_node;
+					while (base_class != nullptr) {
+						if (base_class->has_member(identifier)) {
+							const GDScriptParser::ClassNode::Member &member = base_class->get_member(identifier);
+							if (member.type == GDScriptParser::ClassNode::Member::FUNCTION || member.type == GDScriptParser::ClassNode::Member::SIGNAL) {
+								// Get like it was a property.
+								GDScriptCodeGenerator::Address temp = codegen.add_temporary(); // TODO: Get type here.
+								GDScriptCodeGenerator::Address self(GDScriptCodeGenerator::Address::SELF);
+
+								gen->write_get_named(temp, identifier, self);
+								return temp;
+							}
+						}
+						base_class = base_class->base_type.class_type;
+					}
 
-			// Try class constants.
-			{
-				GDScript *owner = codegen.script;
-				while (owner) {
-					GDScript *scr = owner;
+					// Try in native base.
+					GDScript *scr = codegen.script;
 					GDScriptNativeClass *nc = nullptr;
 					while (scr) {
-						if (scr->constants.has(identifier)) {
-							return codegen.add_constant(scr->constants[identifier]); // TODO: Get type here.
-						}
 						if (scr->native.is_valid()) {
 							nc = scr->native.ptr();
 						}
 						scr = scr->_base;
 					}
 
-					// Class C++ integer constant.
-					if (nc) {
-						bool success = false;
-						int64_t constant = ClassDB::get_integer_constant(nc->get_name(), identifier, &success);
-						if (success) {
-							return codegen.add_constant(constant);
-						}
-					}
+					if (nc && (ClassDB::has_signal(nc->get_name(), identifier) || ClassDB::has_method(nc->get_name(), identifier))) {
+						// Get like it was a property.
+						GDScriptCodeGenerator::Address temp = codegen.add_temporary(); // TODO: Get type here.
+						GDScriptCodeGenerator::Address self(GDScriptCodeGenerator::Address::SELF);
 
-					owner = owner->_owner;
-				}
-			}
+						gen->write_get_named(temp, identifier, self);
+						return temp;
+					}
+				} break;
+				case GDScriptParser::IdentifierNode::MEMBER_CONSTANT:
+				case GDScriptParser::IdentifierNode::MEMBER_CLASS: {
+					// Try class constants.
+					GDScript *owner = codegen.script;
+					while (owner) {
+						GDScript *scr = owner;
+						GDScriptNativeClass *nc = nullptr;
+						while (scr) {
+							if (scr->constants.has(identifier)) {
+								return codegen.add_constant(scr->constants[identifier]); // TODO: Get type here.
+							}
+							if (scr->native.is_valid()) {
+								nc = scr->native.ptr();
+							}
+							scr = scr->_base;
+						}
 
-			// Try signals and methods (can be made callables).
-			{
-				// Search upwards through parent classes:
-				const GDScriptParser::ClassNode *base_class = codegen.class_node;
-				while (base_class != nullptr) {
-					if (base_class->has_member(identifier)) {
-						const GDScriptParser::ClassNode::Member &member = base_class->get_member(identifier);
-						if (member.type == GDScriptParser::ClassNode::Member::FUNCTION || member.type == GDScriptParser::ClassNode::Member::SIGNAL) {
-							// Get like it was a property.
-							GDScriptCodeGenerator::Address temp = codegen.add_temporary(); // TODO: Get type here.
-							GDScriptCodeGenerator::Address self(GDScriptCodeGenerator::Address::SELF);
+						// Class C++ integer constant.
+						if (nc) {
+							bool success = false;
+							int64_t constant = ClassDB::get_integer_constant(nc->get_name(), identifier, &success);
+							if (success) {
+								return codegen.add_constant(constant);
+							}
+						}
 
-							gen->write_get_named(temp, identifier, self);
-							return temp;
+						owner = owner->_owner;
+					}
+				} break;
+				case GDScriptParser::IdentifierNode::STATIC_VARIABLE: {
+					// Try static variables.
+					GDScript *scr = codegen.script;
+					while (scr) {
+						if (scr->static_variables_indices.has(identifier)) {
+							if (scr->static_variables_indices[identifier].getter != StringName() && scr->static_variables_indices[identifier].getter != codegen.function_name) {
+								// Perform getter.
+								GDScriptCodeGenerator::Address temp = codegen.add_temporary(scr->static_variables_indices[identifier].data_type);
+								GDScriptCodeGenerator::Address class_addr(GDScriptCodeGenerator::Address::CLASS);
+								Vector<GDScriptCodeGenerator::Address> args; // No argument needed.
+								gen->write_call(temp, class_addr, scr->static_variables_indices[identifier].getter, args);
+								return temp;
+							} else {
+								// No getter or inside getter: direct variable access.
+								GDScriptCodeGenerator::Address temp = codegen.add_temporary(scr->static_variables_indices[identifier].data_type);
+								GDScriptCodeGenerator::Address _class = codegen.add_constant(scr);
+								int index = scr->static_variables_indices[identifier].index;
+								gen->write_get_static_variable(temp, _class, index);
+								return temp;
+							}
 						}
+						scr = scr->_base;
 					}
-					base_class = base_class->base_type.class_type;
-				}
+				} break;
 
-				// Try in native base.
-				GDScript *scr = codegen.script;
-				GDScriptNativeClass *nc = nullptr;
-				while (scr) {
-					if (scr->native.is_valid()) {
-						nc = scr->native.ptr();
+				// GLOBALS.
+				case GDScriptParser::IdentifierNode::UNDEFINED_SOURCE: {
+					// Try globals.
+					if (GDScriptLanguage::get_singleton()->get_global_map().has(identifier)) {
+						// If it's an autoload singleton, we postpone to load it at runtime.
+						// This is so one autoload doesn't try to load another before it's compiled.
+						HashMap<StringName, ProjectSettings::AutoloadInfo> autoloads = ProjectSettings::get_singleton()->get_autoload_list();
+						if (autoloads.has(identifier) && autoloads[identifier].is_singleton) {
+							GDScriptCodeGenerator::Address global = codegen.add_temporary(_gdtype_from_datatype(in->get_datatype(), codegen.script));
+							int idx = GDScriptLanguage::get_singleton()->get_global_map()[identifier];
+							gen->write_store_global(global, idx);
+							return global;
+						} else {
+							int idx = GDScriptLanguage::get_singleton()->get_global_map()[identifier];
+							Variant global = GDScriptLanguage::get_singleton()->get_global_array()[idx];
+							return codegen.add_constant(global);
+						}
 					}
-					scr = scr->_base;
-				}
-
-				if (nc && (ClassDB::has_signal(nc->get_name(), identifier) || ClassDB::has_method(nc->get_name(), identifier))) {
-					// Get like it was a property.
-					GDScriptCodeGenerator::Address temp = codegen.add_temporary(); // TODO: Get type here.
-					GDScriptCodeGenerator::Address self(GDScriptCodeGenerator::Address::SELF);
-
-					gen->write_get_named(temp, identifier, self);
-					return temp;
-				}
-			}
-
-			// Try globals.
-			if (GDScriptLanguage::get_singleton()->get_global_map().has(identifier)) {
-				// If it's an autoload singleton, we postpone to load it at runtime.
-				// This is so one autoload doesn't try to load another before it's compiled.
-				HashMap<StringName, ProjectSettings::AutoloadInfo> autoloads = ProjectSettings::get_singleton()->get_autoload_list();
-				if (autoloads.has(identifier) && autoloads[identifier].is_singleton) {
-					GDScriptCodeGenerator::Address global = codegen.add_temporary(_gdtype_from_datatype(in->get_datatype(), codegen.script));
-					int idx = GDScriptLanguage::get_singleton()->get_global_map()[identifier];
-					gen->write_store_global(global, idx);
-					return global;
-				} else {
-					int idx = GDScriptLanguage::get_singleton()->get_global_map()[identifier];
-					Variant global = GDScriptLanguage::get_singleton()->get_global_array()[idx];
-					return codegen.add_constant(global);
-				}
-			}
 
-			// Try global classes.
-			if (ScriptServer::is_global_class(identifier)) {
-				const GDScriptParser::ClassNode *class_node = codegen.class_node;
-				while (class_node->outer) {
-					class_node = class_node->outer;
-				}
+					// Try global classes.
+					if (ScriptServer::is_global_class(identifier)) {
+						const GDScriptParser::ClassNode *class_node = codegen.class_node;
+						while (class_node->outer) {
+							class_node = class_node->outer;
+						}
 
-				Ref<Resource> res;
+						Ref<Resource> res;
 
-				if (class_node->identifier && class_node->identifier->name == identifier) {
-					res = Ref<GDScript>(main_script);
-				} else {
-					String global_class_path = ScriptServer::get_global_class_path(identifier);
-					if (ResourceLoader::get_resource_type(global_class_path) == "GDScript") {
-						Error err = OK;
-						res = GDScriptCache::get_full_script(global_class_path, err);
-						if (err != OK) {
-							_set_error("Can't load global class " + String(identifier), p_expression);
-							r_error = ERR_COMPILATION_FAILED;
-							return GDScriptCodeGenerator::Address();
-						}
-					} else {
-						res = ResourceLoader::load(global_class_path);
-						if (res.is_null()) {
-							_set_error("Can't load global class " + String(identifier) + ", cyclic reference?", p_expression);
-							r_error = ERR_COMPILATION_FAILED;
-							return GDScriptCodeGenerator::Address();
+						if (class_node->identifier && class_node->identifier->name == identifier) {
+							res = Ref<GDScript>(main_script);
+						} else {
+							String global_class_path = ScriptServer::get_global_class_path(identifier);
+							if (ResourceLoader::get_resource_type(global_class_path) == "GDScript") {
+								Error err = OK;
+								res = GDScriptCache::get_full_script(global_class_path, err);
+								if (err != OK) {
+									_set_error("Can't load global class " + String(identifier), p_expression);
+									r_error = ERR_COMPILATION_FAILED;
+									return GDScriptCodeGenerator::Address();
+								}
+							} else {
+								res = ResourceLoader::load(global_class_path);
+								if (res.is_null()) {
+									_set_error("Can't load global class " + String(identifier) + ", cyclic reference?", p_expression);
+									r_error = ERR_COMPILATION_FAILED;
+									return GDScriptCodeGenerator::Address();
+								}
+							}
 						}
-					}
-				}
 
-				return codegen.add_constant(res);
-			}
+						return codegen.add_constant(res);
+					}
 
 #ifdef TOOLS_ENABLED
-			if (GDScriptLanguage::get_singleton()->get_named_globals_map().has(identifier)) {
-				GDScriptCodeGenerator::Address global = codegen.add_temporary(); // TODO: Get type.
-				gen->write_store_named_global(global, identifier);
-				return global;
-			}
+					if (GDScriptLanguage::get_singleton()->get_named_globals_map().has(identifier)) {
+						GDScriptCodeGenerator::Address global = codegen.add_temporary(); // TODO: Get type.
+						gen->write_store_named_global(global, identifier);
+						return global;
+					}
 #endif
 
+				} break;
+			}
+
 			// Not found, error.
 			_set_error("Identifier not found: " + String(identifier), p_expression);
 			r_error = ERR_COMPILATION_FAILED;
diff --git a/modules/gdscript/gdscript_editor.cpp b/modules/gdscript/gdscript_editor.cpp
index 47ceee3943..8ad2486e2b 100644
--- a/modules/gdscript/gdscript_editor.cpp
+++ b/modules/gdscript/gdscript_editor.cpp
@@ -1403,7 +1403,7 @@ struct RecursionCheck {
 	}
 };
 
-static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context, const StringName &p_identifier, GDScriptCompletionIdentifier &r_type);
+static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context, const GDScriptParser::IdentifierNode *p_identifier, GDScriptCompletionIdentifier &r_type);
 static bool _guess_identifier_type_from_base(GDScriptParser::CompletionContext &p_context, const GDScriptCompletionIdentifier &p_base, const StringName &p_identifier, GDScriptCompletionIdentifier &r_type);
 static bool _guess_method_return_type_from_base(GDScriptParser::CompletionContext &p_context, const GDScriptCompletionIdentifier &p_base, const StringName &p_method, GDScriptCompletionIdentifier &r_type);
 
@@ -1467,7 +1467,7 @@ static bool _guess_expression_type(GDScriptParser::CompletionContext &p_context,
 			} break;
 			case GDScriptParser::Node::IDENTIFIER: {
 				const GDScriptParser::IdentifierNode *id = static_cast<const GDScriptParser::IdentifierNode *>(p_expression);
-				found = _guess_identifier_type(p_context, id->name, r_type);
+				found = _guess_identifier_type(p_context, id, r_type);
 			} break;
 			case GDScriptParser::Node::DICTIONARY: {
 				// Try to recreate the dictionary.
@@ -1910,7 +1910,7 @@ static bool _guess_expression_type(GDScriptParser::CompletionContext &p_context,
 	return found;
 }
 
-static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context, const StringName &p_identifier, GDScriptCompletionIdentifier &r_type) {
+static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context, const GDScriptParser::IdentifierNode *p_identifier, GDScriptCompletionIdentifier &r_type) {
 	static int recursion_depth = 0;
 	RecursionCheck recursion(&recursion_depth);
 	if (unlikely(recursion.check())) {
@@ -1924,36 +1924,49 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 	GDScriptParser::SuiteNode *suite = p_context.current_suite;
 	bool is_function_parameter = false;
 
-	if (suite) {
-		if (suite->has_local(p_identifier)) {
-			const GDScriptParser::SuiteNode::Local &local = suite->get_local(p_identifier);
+	bool can_be_local = true;
+	switch (p_identifier->source) {
+		case GDScriptParser::IdentifierNode::MEMBER_VARIABLE:
+		case GDScriptParser::IdentifierNode::MEMBER_CONSTANT:
+		case GDScriptParser::IdentifierNode::MEMBER_FUNCTION:
+		case GDScriptParser::IdentifierNode::MEMBER_SIGNAL:
+		case GDScriptParser::IdentifierNode::MEMBER_CLASS:
+		case GDScriptParser::IdentifierNode::INHERITED_VARIABLE:
+		case GDScriptParser::IdentifierNode::STATIC_VARIABLE:
+			can_be_local = false;
+			break;
+		default:
+			break;
+	}
 
-			id_type = local.get_datatype();
+	if (can_be_local && suite && suite->has_local(p_identifier->name)) {
+		const GDScriptParser::SuiteNode::Local &local = suite->get_local(p_identifier->name);
 
-			// Check initializer as the first assignment.
-			switch (local.type) {
-				case GDScriptParser::SuiteNode::Local::VARIABLE:
-					if (local.variable->initializer) {
-						last_assign_line = local.variable->initializer->end_line;
-						last_assigned_expression = local.variable->initializer;
-					}
-					break;
-				case GDScriptParser::SuiteNode::Local::CONSTANT:
-					if (local.constant->initializer) {
-						last_assign_line = local.constant->initializer->end_line;
-						last_assigned_expression = local.constant->initializer;
-					}
-					break;
-				case GDScriptParser::SuiteNode::Local::PARAMETER:
-					if (local.parameter->initializer) {
-						last_assign_line = local.parameter->initializer->end_line;
-						last_assigned_expression = local.parameter->initializer;
-					}
-					is_function_parameter = true;
-					break;
-				default:
-					break;
-			}
+		id_type = local.get_datatype();
+
+		// Check initializer as the first assignment.
+		switch (local.type) {
+			case GDScriptParser::SuiteNode::Local::VARIABLE:
+				if (local.variable->initializer) {
+					last_assign_line = local.variable->initializer->end_line;
+					last_assigned_expression = local.variable->initializer;
+				}
+				break;
+			case GDScriptParser::SuiteNode::Local::CONSTANT:
+				if (local.constant->initializer) {
+					last_assign_line = local.constant->initializer->end_line;
+					last_assigned_expression = local.constant->initializer;
+				}
+				break;
+			case GDScriptParser::SuiteNode::Local::PARAMETER:
+				if (local.parameter->initializer) {
+					last_assign_line = local.parameter->initializer->end_line;
+					last_assigned_expression = local.parameter->initializer;
+				}
+				is_function_parameter = true;
+				break;
+			default:
+				break;
 		}
 	}
 
@@ -1968,7 +1981,7 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 					const GDScriptParser::AssignmentNode *assign = static_cast<const GDScriptParser::AssignmentNode *>(suite->statements[i]);
 					if (assign->end_line > last_assign_line && assign->assignee && assign->assigned_value && assign->assignee->type == GDScriptParser::Node::IDENTIFIER) {
 						const GDScriptParser::IdentifierNode *id = static_cast<const GDScriptParser::IdentifierNode *>(assign->assignee);
-						if (id->name == p_identifier) {
+						if (id->name == p_identifier->name && id->source == p_identifier->source) {
 							last_assign_line = assign->assigned_value->end_line;
 							last_assigned_expression = assign->assigned_value;
 						}
@@ -1986,7 +1999,7 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 			// Credit: Zylann.
 			// TODO: this could be hacked to detect ANDed conditions too...
 			const GDScriptParser::TypeTestNode *type_test = static_cast<const GDScriptParser::TypeTestNode *>(suite->parent_if->condition);
-			if (type_test->operand && type_test->test_type && type_test->operand->type == GDScriptParser::Node::IDENTIFIER && static_cast<const GDScriptParser::IdentifierNode *>(type_test->operand)->name == p_identifier) {
+			if (type_test->operand && type_test->test_type && type_test->operand->type == GDScriptParser::Node::IDENTIFIER && static_cast<const GDScriptParser::IdentifierNode *>(type_test->operand)->name == p_identifier->name && static_cast<const GDScriptParser::IdentifierNode *>(type_test->operand)->source == p_identifier->source) {
 				// Bingo.
 				GDScriptParser::CompletionContext c = p_context;
 				c.current_line = type_test->operand->start_line;
@@ -2022,8 +2035,8 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 				case GDScriptParser::DataType::CLASS:
 					if (base_type.class_type->has_function(p_context.current_function->identifier->name)) {
 						GDScriptParser::FunctionNode *parent_function = base_type.class_type->get_member(p_context.current_function->identifier->name).function;
-						if (parent_function->parameters_indices.has(p_identifier)) {
-							const GDScriptParser::ParameterNode *parameter = parent_function->parameters[parent_function->parameters_indices[p_identifier]];
+						if (parent_function->parameters_indices.has(p_identifier->name)) {
+							const GDScriptParser::ParameterNode *parameter = parent_function->parameters[parent_function->parameters_indices[p_identifier->name]];
 							if ((!id_type.is_set() || id_type.is_variant()) && parameter->get_datatype().is_hard_type()) {
 								id_type = parameter->get_datatype();
 							}
@@ -2048,7 +2061,7 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 					MethodInfo info;
 					if (ClassDB::get_method_info(base_type.native_type, p_context.current_function->identifier->name, &info)) {
 						for (const PropertyInfo &E : info.arguments) {
-							if (E.name == p_identifier) {
+							if (E.name == p_identifier->name) {
 								r_type = _type_from_property(E);
 								return true;
 							}
@@ -2076,14 +2089,14 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 		base.type.class_type = p_context.current_class;
 		base.type.is_meta_type = p_context.current_function && p_context.current_function->is_static;
 
-		if (_guess_identifier_type_from_base(p_context, base, p_identifier, r_type)) {
+		if (_guess_identifier_type_from_base(p_context, base, p_identifier->name, r_type)) {
 			return true;
 		}
 	}
 
 	// Check global scripts.
-	if (ScriptServer::is_global_class(p_identifier)) {
-		String script = ScriptServer::get_global_class_path(p_identifier);
+	if (ScriptServer::is_global_class(p_identifier->name)) {
+		String script = ScriptServer::get_global_class_path(p_identifier->name);
 		if (script.to_lower().ends_with(".gd")) {
 			Error err = OK;
 			Ref<GDScriptParserRef> parser = GDScriptCache::get_parser(script, GDScriptParserRef::INTERFACE_SOLVED, err);
@@ -2099,7 +2112,7 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 				return true;
 			}
 		} else {
-			Ref<Script> scr = ResourceLoader::load(ScriptServer::get_global_class_path(p_identifier));
+			Ref<Script> scr = ResourceLoader::load(ScriptServer::get_global_class_path(p_identifier->name));
 			if (scr.is_valid()) {
 				r_type = _type_from_variant(scr);
 				r_type.type.is_meta_type = true;
@@ -2110,20 +2123,20 @@ static bool _guess_identifier_type(GDScriptParser::CompletionContext &p_context,
 	}
 
 	// Check global variables (including autoloads).
-	if (GDScriptLanguage::get_singleton()->get_named_globals_map().has(p_identifier)) {
-		r_type = _type_from_variant(GDScriptLanguage::get_singleton()->get_named_globals_map()[p_identifier]);
+	if (GDScriptLanguage::get_singleton()->get_named_globals_map().has(p_identifier->name)) {
+		r_type = _type_from_variant(GDScriptLanguage::get_singleton()->get_named_globals_map()[p_identifier->name]);
 		return true;
 	}
 
 	// Check ClassDB.
-	if (ClassDB::class_exists(p_identifier) && ClassDB::is_class_exposed(p_identifier)) {
+	if (ClassDB::class_exists(p_identifier->name) && ClassDB::is_class_exposed(p_identifier->name)) {
 		r_type.type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
 		r_type.type.kind = GDScriptParser::DataType::NATIVE;
-		r_type.type.native_type = p_identifier;
+		r_type.type.native_type = p_identifier->name;
 		r_type.type.is_constant = true;
-		if (Engine::get_singleton()->has_singleton(p_identifier)) {
+		if (Engine::get_singleton()->has_singleton(p_identifier->name)) {
 			r_type.type.is_meta_type = false;
-			r_type.value = Engine::get_singleton()->get_singleton_object(p_identifier);
+			r_type.value = Engine::get_singleton()->get_singleton_object(p_identifier->name);
 		} else {
 			r_type.type.is_meta_type = true;
 			r_type.value = Variant();
diff --git a/modules/gdscript/gdscript_parser.cpp b/modules/gdscript/gdscript_parser.cpp
index a6f83146a0..0e602561c6 100644
--- a/modules/gdscript/gdscript_parser.cpp
+++ b/modules/gdscript/gdscript_parser.cpp
@@ -2280,6 +2280,9 @@ GDScriptParser::ExpressionNode *GDScriptParser::parse_identifier(ExpressionNode
 	IdentifierNode *identifier = alloc_node<IdentifierNode>();
 	complete_extents(identifier);
 	identifier->name = previous.get_identifier();
+#ifdef DEBUG_ENABLED
+	identifier->suite = current_suite;
+#endif
 
 	if (current_suite != nullptr && current_suite->has_local(identifier->name)) {
 		const SuiteNode::Local &declaration = current_suite->get_local(identifier->name);
diff --git a/modules/gdscript/gdscript_parser.h b/modules/gdscript/gdscript_parser.h
index dd4e05b613..20f5dcf06d 100644
--- a/modules/gdscript/gdscript_parser.h
+++ b/modules/gdscript/gdscript_parser.h
@@ -859,19 +859,24 @@ public:
 
 	struct IdentifierNode : public ExpressionNode {
 		StringName name;
+#ifdef DEBUG_ENABLED
+		SuiteNode *suite = nullptr; // The block in which the identifier is used.
+#endif
 
 		enum Source {
 			UNDEFINED_SOURCE,
 			FUNCTION_PARAMETER,
-			LOCAL_CONSTANT,
 			LOCAL_VARIABLE,
+			LOCAL_CONSTANT,
 			LOCAL_ITERATOR, // `for` loop iterator.
 			LOCAL_BIND, // Pattern bind.
-			MEMBER_SIGNAL,
 			MEMBER_VARIABLE,
-			STATIC_VARIABLE,
 			MEMBER_CONSTANT,
+			MEMBER_FUNCTION,
+			MEMBER_SIGNAL,
+			MEMBER_CLASS,
 			INHERITED_VARIABLE,
+			STATIC_VARIABLE,
 		};
 		Source source = UNDEFINED_SOURCE;
 
diff --git a/modules/gdscript/gdscript_warning.cpp b/modules/gdscript/gdscript_warning.cpp
index 8de78d2b9a..24aa793c47 100644
--- a/modules/gdscript/gdscript_warning.cpp
+++ b/modules/gdscript/gdscript_warning.cpp
@@ -136,6 +136,12 @@ String GDScriptWarning::get_message() const {
 		case CONFUSABLE_IDENTIFIER:
 			CHECK_SYMBOLS(1);
 			return vformat(R"(The identifier "%s" has misleading characters and might be confused with something else.)", symbols[0]);
+		case CONFUSABLE_LOCAL_DECLARATION:
+			CHECK_SYMBOLS(2);
+			return vformat(R"(The %s "%s" is declared below in the parent block.)", symbols[0], symbols[1]);
+		case CONFUSABLE_LOCAL_USAGE:
+			CHECK_SYMBOLS(1);
+			return vformat(R"(The identifier "%s" will be shadowed below in the block.)", symbols[0]);
 		case INFERENCE_ON_VARIANT:
 			CHECK_SYMBOLS(1);
 			return vformat("The %s type is being inferred from a Variant value, so it will be typed as Variant.", symbols[0]);
@@ -213,6 +219,8 @@ String GDScriptWarning::get_name_from_code(Code p_code) {
 		"DEPRECATED_KEYWORD",
 		"RENAMED_IN_GODOT_4_HINT",
 		"CONFUSABLE_IDENTIFIER",
+		"CONFUSABLE_LOCAL_DECLARATION",
+		"CONFUSABLE_LOCAL_USAGE",
 		"INFERENCE_ON_VARIANT",
 		"NATIVE_METHOD_OVERRIDE",
 		"GET_NODE_DEFAULT_WITHOUT_ONREADY",
diff --git a/modules/gdscript/gdscript_warning.h b/modules/gdscript/gdscript_warning.h
index ae6207fcdc..8444d46a88 100644
--- a/modules/gdscript/gdscript_warning.h
+++ b/modules/gdscript/gdscript_warning.h
@@ -83,6 +83,8 @@ public:
 		DEPRECATED_KEYWORD, // The keyword is deprecated and should be replaced.
 		RENAMED_IN_GODOT_4_HINT, // A variable or function that could not be found has been renamed in Godot 4.
 		CONFUSABLE_IDENTIFIER, // The identifier contains misleading characters that can be confused. E.g. "usеr" (has Cyrillic "е" instead of Latin "e").
+		CONFUSABLE_LOCAL_DECLARATION, // The parent block declares an identifier with the same name below.
+		CONFUSABLE_LOCAL_USAGE, // The identifier will be shadowed below in the block.
 		INFERENCE_ON_VARIANT, // The declaration uses type inference but the value is typed as Variant.
 		NATIVE_METHOD_OVERRIDE, // The script method overrides a native one, this may not work as intended.
 		GET_NODE_DEFAULT_WITHOUT_ONREADY, // A class variable uses `get_node()` (or the `$` notation) as its default value, but does not use the @onready annotation.
@@ -128,6 +130,8 @@ public:
 		WARN, // DEPRECATED_KEYWORD
 		WARN, // RENAMED_IN_GODOT_4_HINT
 		WARN, // CONFUSABLE_IDENTIFIER
+		WARN, // CONFUSABLE_LOCAL_DECLARATION
+		WARN, // CONFUSABLE_LOCAL_USAGE
 		ERROR, // INFERENCE_ON_VARIANT // Most likely done by accident, usually inference is trying for a particular type.
 		ERROR, // NATIVE_METHOD_OVERRIDE // May not work as expected.
 		ERROR, // GET_NODE_DEFAULT_WITHOUT_ONREADY // May not work as expected.
diff --git a/modules/gdscript/tests/scripts/analyzer/errors/cyclic_ref_var_self.gd b/modules/gdscript/tests/scripts/analyzer/errors/cyclic_ref_var_self.gd
new file mode 100644
index 0000000000..57ae41922f
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/errors/cyclic_ref_var_self.gd
@@ -0,0 +1,4 @@
+var v1 = v1
+
+func test():
+	print(v1)
diff --git a/modules/gdscript/tests/scripts/analyzer/errors/cyclic_ref_var_self.out b/modules/gdscript/tests/scripts/analyzer/errors/cyclic_ref_var_self.out
new file mode 100644
index 0000000000..c337882d9c
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/errors/cyclic_ref_var_self.out
@@ -0,0 +1,2 @@
+GDTEST_ANALYZER_ERROR
+Could not resolve member "v1": Cyclic reference.
diff --git a/modules/gdscript/tests/scripts/analyzer/features/typed_array_usage.gd b/modules/gdscript/tests/scripts/analyzer/features/typed_array_usage.gd
index c4108f50de..b000c82717 100644
--- a/modules/gdscript/tests/scripts/analyzer/features/typed_array_usage.gd
+++ b/modules/gdscript/tests/scripts/analyzer/features/typed_array_usage.gd
@@ -126,7 +126,7 @@ func test():
 	assert(a_objects.get_typed_builtin() == TYPE_OBJECT)
 	assert(a_objects.get_typed_script() == A)
 
-	var a_passed = (func check_a_passing(a_objects: Array[A]): return a_objects.size()).call(a_objects)
+	var a_passed = (func check_a_passing(p_objects: Array[A]): return p_objects.size()).call(a_objects)
 	assert(a_passed == 4)
 
 	var b_passed = (func check_b_passing(basic: Array): return basic[0] != null).call(b_objects)
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_declaration.gd b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_declaration.gd
new file mode 100644
index 0000000000..3178f8d496
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_declaration.gd
@@ -0,0 +1,6 @@
+func test():
+	if true:
+		var a = 1
+		print(a)
+	var a = 2
+	print(a)
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_declaration.out b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_declaration.out
new file mode 100644
index 0000000000..7365072ea7
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_declaration.out
@@ -0,0 +1,7 @@
+GDTEST_OK
+>> WARNING
+>> Line: 3
+>> CONFUSABLE_LOCAL_DECLARATION
+>> The variable "a" is declared below in the parent block.
+1
+2
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage.gd b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage.gd
new file mode 100644
index 0000000000..4462c067bc
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage.gd
@@ -0,0 +1,6 @@
+var a = 1
+
+func test():
+	print(a)
+	var a = 2
+	print(a)
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage.out b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage.out
new file mode 100644
index 0000000000..0e0d607831
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage.out
@@ -0,0 +1,11 @@
+GDTEST_OK
+>> WARNING
+>> Line: 4
+>> CONFUSABLE_LOCAL_USAGE
+>> The identifier "a" will be shadowed below in the block.
+>> WARNING
+>> Line: 5
+>> SHADOWED_VARIABLE
+>> The local variable "a" is shadowing an already-declared variable at line 1.
+1
+2
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_initializer.gd b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_initializer.gd
new file mode 100644
index 0000000000..eef8eb66e6
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_initializer.gd
@@ -0,0 +1,6 @@
+var a = 1
+
+func test():
+	print(a)
+	var a = a + 1
+	print(a)
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_initializer.out b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_initializer.out
new file mode 100644
index 0000000000..228a510490
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_initializer.out
@@ -0,0 +1,15 @@
+GDTEST_OK
+>> WARNING
+>> Line: 4
+>> CONFUSABLE_LOCAL_USAGE
+>> The identifier "a" will be shadowed below in the block.
+>> WARNING
+>> Line: 5
+>> CONFUSABLE_LOCAL_USAGE
+>> The identifier "a" will be shadowed below in the block.
+>> WARNING
+>> Line: 5
+>> SHADOWED_VARIABLE
+>> The local variable "a" is shadowing an already-declared variable at line 1.
+1
+2
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_loop.gd b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_loop.gd
new file mode 100644
index 0000000000..1f207f27ac
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_loop.gd
@@ -0,0 +1,7 @@
+var a = 1
+
+func test():
+	for _i in 3:
+		print(a)
+		var a = 2
+		print(a)
diff --git a/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_loop.out b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_loop.out
new file mode 100644
index 0000000000..0d20e9f7a0
--- /dev/null
+++ b/modules/gdscript/tests/scripts/analyzer/warnings/confusable_local_usage_loop.out
@@ -0,0 +1,15 @@
+GDTEST_OK
+>> WARNING
+>> Line: 5
+>> CONFUSABLE_LOCAL_USAGE
+>> The identifier "a" will be shadowed below in the block.
+>> WARNING
+>> Line: 6
+>> SHADOWED_VARIABLE
+>> The local variable "a" is shadowing an already-declared variable at line 1.
+1
+2
+1
+2
+1
+2