Revert "look at whether the variable was mutated or reassigned instead"

This reverts commit 73586aa.

packages/svelte/src/compiler/compile/Component.js

@@ -770,12 +770,25 @@ export default class Component {
 			if (name[0] === '$') {
 				return this.error(/** @type {any} */ (node), compiler_errors.illegal_declaration);
 			}
-			const { type } = node;
+			const writable =
+				node.type === 'VariableDeclaration' && (node.kind === 'var' || node.kind === 'let');
+
+			let immutable = false;
+			if (node.type === 'VariableDeclaration' && node.kind === 'const') {
+				immutable = true;
+				for (const declaration of node.declarations) {
+					if (declaration.init.type !== 'Literal') {
+						immutable = false;
+					}
+				}
+			}
+
 			this.add_var(node, {
 				name,
 				initialised: instance_scope.initialised_declarations.has(name),
-				imported: type.startsWith('Import'),
-				writable: type === 'VariableDeclaration' && (node.kind === 'var' || node.kind === 'let')
+				imported: node.type.startsWith('Import'),
+				writable,
+				immutable
 			});
 			this.node_for_declaration.set(name, node);
 		});

packages/svelte/src/compiler/compile/nodes/shared/Expression.js

@@ -129,11 +129,8 @@ export default class Expression {
 								.forEach((name) => dependencies.add(name));
 						}
 					} else {
-						if (!lazy) {
-							const variable = component.var_lookup.get(name);
-							if (!variable || !variable.imported || variable.mutated || variable.reassigned) {
-								dependencies.add(name);
-							}
+						if (!lazy && !component.var_lookup.get(name)?.immutable) {
+							dependencies.add(name);
 						}
 						component.add_reference(node, name);
 						component.warn_if_undefined(name, nodes[0], template_scope, owner);

packages/svelte/src/compiler/interfaces.d.ts

@@ -383,6 +383,7 @@ export interface Var {
 	writable?: boolean;
 
 	// used internally, but not exposed
+	immutable?: boolean;
 	global?: boolean;
 	internal?: boolean; // event handlers, bindings
 	initialised?: boolean;