use unique name for rects

src/compile/nodes/EachBlock.ts

@@ -314,13 +314,15 @@ export default class EachBlock extends Node {
 
 		const dynamic = this.block.hasUpdateMethod;
 
+		const rects = block.getUniqueName('rects');
+
 		block.builders.update.addBlock(deindent`
 			const ${this.each_block_value} = ${snippet};
 
 			${this.block.hasOutroMethod && `@transitionManager.groupOutros();`}
-			${this.block.animation && `const rects = @measure(${blocks});`}
+			${this.block.animation && `const ${rects} = @measure(${blocks});`}
 			${blocks} = @updateKeyedEach(${blocks}, #component, changed, ${get_key}, ${dynamic ? '1' : '0'}, ctx, ${this.each_block_value}, ${lookup}, ${updateMountNode}, ${String(this.block.hasOutroMethod)}, ${create_each_block}, "${mountOrIntro}", ${anchor}, ${this.get_each_context});
-			${this.block.animation && `@animate(${blocks}, rects, %animations-${this.children[0].animation.name}, {});`}
+			${this.block.animation && `@animate(${blocks}, ${rects}, %animations-${this.children[0].animation.name}, {});`}
 		`);
 
 		if (this.compiler.options.nestedTransitions) {