fix: create fewer deriveds for concatenated strings (#15041)

* fix: create fewer deriveds for concatenated strings

* stringified_text -> expression

Author: Rich-Harris

.changeset/rich-donkeys-wink.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: create fewer deriveds for concatenated strings

packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js

@@ -47,8 +47,8 @@ export function build_template_chunk(values, visit, state) {
 				quasi.value.cooked += node.expression.value + '';
 			}
 		} else {
-			if (contains_multiple_call_expression) {
-				const id = b.id(state.scope.generate('stringified_text'));
+			if (node.metadata.expression.has_call && contains_multiple_call_expression) {
+				const id = b.id(state.scope.generate('expression'));
 				state.init.push(
 					b.const(
 						id,

packages/svelte/tests/snapshot/samples/text-nodes-deriveds/_expected/client/index.svelte.js

@@ -16,11 +16,11 @@ export default function Text_nodes_deriveds($$anchor) {
 	}
 
 	var p = root();
-	const stringified_text = $.derived(() => text1() ?? '');
-	const stringified_text_1 = $.derived(() => text2() ?? '');
+	const expression = $.derived(() => text1() ?? '');
+	const expression_1 = $.derived(() => text2() ?? '');
 	var text = $.child(p);
 
-	$.template_effect(() => $.set_text(text, `${$.get(stringified_text)}${$.get(stringified_text_1)}`));
+	$.template_effect(() => $.set_text(text, `${$.get(expression)}${$.get(expression_1)}`));
 	$.reset(p);
 	$.append($$anchor, p);
 }