skip transition code where possible

src/compile/render-dom/Block.ts

@@ -174,13 +174,15 @@ export default class Block {
 		}
 	}
 
-	addIntro() {
+	addIntro(local?: boolean) {
 		this.hasIntros = this.hasIntroMethod = this.renderer.hasIntroTransitions = true;
+		if (!local && this.parent) this.parent.addIntro();
 	}
 
-	addOutro() {
+	addOutro(local?: boolean) {
 		this.hasOutros = this.hasOutroMethod = this.renderer.hasOutroTransitions = true;
 		this.outros += 1;
+		if (!local && this.parent) this.parent.addOutro();
 	}
 
 	addAnimation() {

src/compile/render-dom/wrappers/Element/index.ts

@@ -162,8 +162,8 @@ export default class ElementWrapper extends Wrapper {
 		this.bindings = this.node.bindings.map(binding => new Binding(block, binding, this));
 
 		if (node.intro || node.outro) {
-			if (node.intro) block.addIntro();
-			if (node.outro) block.addOutro();
+			if (node.intro) block.addIntro(node.intro.is_local);
+			if (node.outro) block.addOutro(node.outro.is_local);
 		}
 
 		if (node.animation) {

src/compile/render-dom/wrappers/IfBlock.ts

@@ -125,9 +125,6 @@ export default class IfBlockWrapper extends Wrapper {
 
 		createBranches(this.node);
 
-		if (hasIntros) block.addIntro();
-		if (hasOutros) block.addOutro();
-
 		blocks.forEach(block => {
 			block.hasUpdateMethod = isDynamic;
 			block.hasIntroMethod = hasIntros;

test/js/samples/transition-local/expected.js

@@ -0,0 +1,162 @@
+/* generated by Svelte vX.Y.Z */
+import { SvelteComponent as SvelteComponent_1, add_render_callback, createComment, createElement, create_in_transition, detachNode, flush, init, insert, noop, safe_not_equal } from "svelte/internal";
+
+// (8:0) {#if x}
+function create_if_block(ctx) {
+	var if_block_anchor;
+
+	var if_block = (ctx.y) && create_if_block_1(ctx);
+
+	return {
+		c() {
+			if (if_block) if_block.c();
+			if_block_anchor = createComment();
+		},
+
+		m(target, anchor) {
+			if (if_block) if_block.m(target, anchor);
+			insert(target, if_block_anchor, anchor);
+		},
+
+		p(changed, ctx) {
+			if (ctx.y) {
+				if (!if_block) {
+					if_block = create_if_block_1(ctx);
+					if_block.c();
+					if_block.m(if_block_anchor.parentNode, if_block_anchor);
+				}
+				if_block.i(1);
+			} else if (if_block) {
+				if_block.d(1);
+				if_block = null;
+			}
+		},
+
+		d(detach) {
+			if (if_block) if_block.d(detach);
+
+			if (detach) {
+				detachNode(if_block_anchor);
+			}
+		}
+	};
+}
+
+// (9:1) {#if y}
+function create_if_block_1(ctx) {
+	var div, div_intro;
+
+	return {
+		c() {
+			div = createElement("div");
+			div.textContent = "...";
+		},
+
+		m(target, anchor) {
+			insert(target, div, anchor);
+		},
+
+		i(local) {
+			if (local) {
+				if (!div_intro) {
+					add_render_callback(() => {
+						div_intro = create_in_transition(div, foo, {});
+						div_intro.start();
+					});
+				}
+			}
+		},
+
+		o: noop,
+
+		d(detach) {
+			if (detach) {
+				detachNode(div);
+			}
+		}
+	};
+}
+
+function create_fragment(ctx) {
+	var if_block_anchor;
+
+	var if_block = (ctx.x) && create_if_block(ctx);
+
+	return {
+		c() {
+			if (if_block) if_block.c();
+			if_block_anchor = createComment();
+		},
+
+		m(target, anchor) {
+			if (if_block) if_block.m(target, anchor);
+			insert(target, if_block_anchor, anchor);
+		},
+
+		p(changed, ctx) {
+			if (ctx.x) {
+				if (if_block) {
+					if_block.p(changed, ctx);
+				} else {
+					if_block = create_if_block(ctx);
+					if_block.c();
+					if_block.m(if_block_anchor.parentNode, if_block_anchor);
+				}
+			} else if (if_block) {
+				if_block.d(1);
+				if_block = null;
+			}
+		},
+
+		i: noop,
+		o: noop,
+
+		d(detach) {
+			if (if_block) if_block.d(detach);
+
+			if (detach) {
+				detachNode(if_block_anchor);
+			}
+		}
+	};
+}
+
+function foo() {}
+
+function instance($$self, $$props, $$invalidate) {
+	let { x, y } = $$props;
+
+	$$self.$set = $$props => {
+		if ('x' in $$props) $$invalidate('x', x = $$props.x);
+		if ('y' in $$props) $$invalidate('y', y = $$props.y);
+	};
+
+	return { x, y };
+}
+
+class SvelteComponent extends SvelteComponent_1 {
+	constructor(options) {
+		super();
+		init(this, options, instance, create_fragment, safe_not_equal);
+	}
+
+	get x() {
+		return this.$$.ctx.x;
+	}
+
+	set x(x) {
+		this.$set({ x });
+		flush();
+	}
+
+	get y() {
+		return this.$$.ctx.y;
+	}
+
+	set y(y) {
+		this.$set({ y });
+		flush();
+	}
+}
+
+export default SvelteComponent;

test/js/samples/transition-local/input.html

@@ -0,0 +1,12 @@
+<script>
+	export let x;
+	export let y;
+
+	function foo() {}
+</script>
+
+{#if x}
+	{#if y}
+		<div in:foo|local>...</div>
+	{/if}
+{/if}