fix each block destructuring can't have default values refered to destructured params

src/compiler/compile/nodes/shared/Context.ts

@@ -25,7 +25,15 @@ export function unpack_destructuring(contexts: Context[], node: Node, modifier:
 			if (element && element.type === 'RestElement') {
 				unpack_destructuring(contexts, element, node => x`${modifier(node)}.slice(${i})` as Node);
 			} else if (element && element.type === 'AssignmentPattern') {
-				unpack_destructuring(contexts, element.left, node => x`${modifier(node)}[${i}] !== undefined ? ${modifier(node)}[${i}] : ${element.right}` as Node);
+				const n = contexts.length;
+
+				unpack_destructuring(contexts, element.left, node => {
+					const alternate = JSON.parse(JSON.stringify(element.right));
+
+					update_reference(contexts.slice(0, n), node, alternate);
+
+					return x`${modifier(node)}[${i}] !== undefined ? ${modifier(node)}[${i}] : ${alternate.replacement || alternate}` as Node
+				});
 			} else {
 				unpack_destructuring(contexts, element, node => x`${modifier(node)}[${i}]` as Node);
 			}
@@ -44,9 +52,17 @@ export function unpack_destructuring(contexts: Context[], node: Node, modifier:
 				const key = property.key as Identifier;
 				const value = property.value;
 
-				used_properties.push(x`"${(key as Identifier).name}"`);
+				used_properties.push(x`"${key.name}"`);
 				if (value.type === 'AssignmentPattern') {
-					unpack_destructuring(contexts, value.left, node => x`${modifier(node)}.${key.name} !== undefined ? ${modifier(node)}.${key.name} : ${value.right}` as Node);
+					const n = contexts.length;
+
+					unpack_destructuring(contexts, value.left, node => {
+						const alternate = JSON.parse(JSON.stringify(value.right));
+
+						update_reference(contexts.slice(0, n), node, alternate);
+
+						return x`${modifier(node)}.${key.name} !== undefined ? ${modifier(node)}.${key.name} : ${alternate.replacement || alternate}` as Node
+					});
 				} else {
 					unpack_destructuring(contexts, value, node => x`${modifier(node)}.${key.name}` as Node);
 				}
@@ -54,3 +70,37 @@ export function unpack_destructuring(contexts: Context[], node: Node, modifier:
 		});
 	}
 }
+
+function update_reference(contexts: Context[], node: Node, parent: any, property?: any) {
+	const current_node = (property !== undefined && parent[property] || parent);
+
+	if (!current_node || !contexts.length) return;
+
+	if (current_node.type === 'Identifier') {
+		contexts.forEach((context) => {
+			const { key, modifier } = context;
+
+			if (current_node.name === key.name) {
+				const replacement = modifier(node);
+				
+				if (property === undefined) {
+					current_node.replacement = replacement;
+				} else {
+					parent[property] = replacement;
+				}
+			}
+		});
+	} else if (current_node.type === 'BinaryExpression') {
+		update_reference(contexts, node, current_node, 'left');
+		update_reference(contexts, node, current_node, 'right');
+	} else if (current_node.type === 'CallExpression') {
+		for (let i = 0; i < current_node.arguments.length; i += 1) {
+			update_reference(contexts, node, current_node.arguments, i);
+		}
+
+		update_reference(contexts, node, current_node, 'callee');
+	} else if (current_node.type === 'MemberExpression') {
+		update_reference(contexts, node, current_node, 'object');
+		update_reference(contexts, node, current_node, 'property');
+	}
+}

test/runtime/samples/each-block-destructured-default/_config.js

@@ -7,16 +7,14 @@ export default {
 	},
 
 	html: `
-		<p class="mammal">raccoon - P. lotor - 25kg</p>
+		<p class="mammal">raccoon - P. lotor - 25kg (55 lb)</p>
-		<p class="bird">eagle - unknown - 5.4kg</p>
+		<p class="bird">eagle - unknown - 5.4kg (12 lb)</p>
 	`,
 
-	
-
 	test({ assert, component, target }) {
 		component.animalEntries = [{ animal: 'cow', class: 'mammal', species: '‎B. taurus' }];
 		assert.htmlEqual(target.innerHTML, `
-			<p class="mammal">cow - ‎B. taurus - 50kg</p>
+			<p class="mammal">cow - ‎B. taurus - 50kg (110 lb)</p>
 		`);
 	},
 };

test/runtime/samples/each-block-destructured-default/main.svelte

@@ -2,6 +2,6 @@
 	export let animalEntries;
 </script>
 
-{#each animalEntries as { animal, species = 'unknown', kilogram: weight = 50 , ...props } }
+{#each animalEntries as { animal, species = 'unknown', kilogram: weight = 50, pound = (weight * 2.2).toFixed(0), ...props } }
-	<p {...props}>{animal} - {species} - {weight}kg</p>
+	<p {...props}>{animal} - {species} - {weight}kg ({pound} lb)</p>
 {/each}