update simple if-blocks with complex but static conditions

src/compiler/compile/render_dom/wrappers/IfBlock.ts

@@ -493,6 +493,10 @@ export default class IfBlockWrapper extends Wrapper {
 					}
 				`);
 			}
+		} else if (dynamic) {
+			block.builders.update.add_block(
+				`if (${branch.condition}) ${name}.p(changed, ctx);`
+			);
 		}
 
 		block.builders.destroy.add_line(`${if_name}${name}.d(${detaching});`);

test/runtime/samples/if-block-static-with-dynamic-contents/_config.js

@@ -0,0 +1,12 @@
+export default {
+	props: {
+		foo: 42
+	},
+
+	html: '<p>42</p>',
+
+	test({ assert, component, target }) {
+		component.foo = 43;
+		assert.htmlEqual(target.innerHTML, '<p>43</p>');
+	}
+};

test/runtime/samples/if-block-static-with-dynamic-contents/main.svelte

@@ -0,0 +1,9 @@
+<script>
+	export let foo;
+
+	const show = () => true;
+</script>
+
+{#if show()}
+	<p>{foo}</p>
+{/if}