[fix] be able to silence more warnings

including css-unused-selector, unused-export-let, module-script-reactive-declaration
Fixes #5954
Related to #5281

src/compiler/compile/Component.ts

@@ -36,6 +36,7 @@ import { DecodedSourceMap, RawSourceMap } from '@ampproject/remapping/dist/types
 import { clone } from '../utils/clone';
 import compiler_warnings from './compiler_warnings';
 import compiler_errors from './compiler_errors';
+import { extract_svelte_ignore_from_comments } from './utils/extract_svelte_ignore';
 
 interface ComponentOptions {
 	namespace?: string;
@@ -476,6 +477,14 @@ export default class Component {
 	}
 
 	extract_exports(node) {
+		const ignores = extract_svelte_ignore_from_comments(node);
+		if (ignores.length) this.push_ignores(ignores);
+		const result = this._extract_exports(node);
+		if (ignores.length) this.pop_ignores();
+		return result;
+	}
+
+	private _extract_exports(node) {
 		if (node.type === 'ExportDefaultDeclaration') {
 			this.error(node, compiler_errors.default_export);
 		}
@@ -1169,6 +1178,9 @@ export default class Component {
 		}> = [];
 
 		this.ast.instance.content.body.forEach(node => {
+			const ignores = extract_svelte_ignore_from_comments(node);
+			if (ignores.length) this.push_ignores(ignores);
+
 			if (node.type === 'LabeledStatement' && node.label.name === '$') {
 				this.reactive_declaration_nodes.add(node);
 
@@ -1246,6 +1258,8 @@ export default class Component {
 					declaration
 				});
 			}
+
+			if (ignores.length) this.pop_ignores();
 		});
 
 		const lookup = new Map();

src/compiler/compile/css/Stylesheet.ts

@@ -7,6 +7,7 @@ import Component from '../Component';
 import { CssNode } from './interfaces';
 import hash from '../utils/hash';
 import compiler_warnings from '../compiler_warnings';
+import { extract_svelte_ignore } from '../utils/extract_svelte_ignore';
 
 function remove_css_prefix(name: string): string {
 	return name.replace(/^-((webkit)|(moz)|(o)|(ms))-/, '');
@@ -447,10 +448,37 @@ export default class Stylesheet {
 	}
 
 	warn_on_unused_selectors(component: Component) {
+		const ignores = this.get_ignores();
+		if (ignores.length) component.push_ignores(ignores);
+
 		this.children.forEach(child => {
 			child.warn_on_unused_selector((selector: Selector) => {
 				component.warn(selector.node, compiler_warnings.css_unused_selector(this.source.slice(selector.node.start, selector.node.end)));
 			});
 		});
+
+		if (ignores.length) component.pop_ignores();
+	}
+
+	private get_ignores(): string[] {
+		const previous_node_idx = !this.ast.css ? -1 : this.ast.html.children.findIndex(child => child.end === this.ast.css.start);
+		if (previous_node_idx === -1) {
+			return [];
+		}
+
+		for (let i = previous_node_idx; i >= 0; i--) {
+			const node = this.ast.html.children[i];
+			if (node.type !== 'Comment' && node.type !== 'Text') {
+				return [];
+			}
+			if (node.type === 'Comment') {
+				const ignores = extract_svelte_ignore(node.data || '');
+				if (ignores.length) {
+					return ignores;
+				}
+			}
+		}
+
+		return [];
 	}
 }

src/compiler/compile/nodes/Comment.ts

@@ -1,10 +1,9 @@
 import { TemplateNode } from '../../interfaces';
 import Component from '../Component';
+import { extract_svelte_ignore } from '../utils/extract_svelte_ignore';
 import Node from './shared/Node';
 import TemplateScope from './shared/TemplateScope';
 
-const pattern = /^\s*svelte-ignore\s+([\s\S]+)\s*$/m;
-
 export default class Comment extends Node {
 	type: 'Comment';
 	data: string;
@@ -13,8 +12,6 @@ export default class Comment extends Node {
 	constructor(component: Component, parent: Node, scope: TemplateScope, info: TemplateNode) {
 		super(component, parent, scope, info);
 		this.data = info.data;
-
-		const match = pattern.exec(this.data);
-		this.ignores = match ? match[1].split(/[^\S]/).map(x => x.trim()).filter(Boolean) : [];
+		this.ignores = extract_svelte_ignore(this.data)
 	}
 }

src/compiler/compile/render_dom/index.ts

@@ -10,6 +10,7 @@ import { ClassDeclaration, FunctionExpression, Node, Statement, ObjectExpression
 import { apply_preprocessor_sourcemap } from '../../utils/mapped_code';
 import { RawSourceMap, DecodedSourceMap } from '@ampproject/remapping/dist/types/types';
 import { Node as PeriscopicNode } from 'periscopic';
+import { flatten } from '../utils/flatten';
 
 export default function dom(
 	component: Component,
@@ -551,18 +552,5 @@ export default function dom(
 		body.push(declaration);
 	}
 
-	return { js: flatten(body, []), css };
-}
-
-function flatten(nodes: any[], target: any[]) {
-	for (let i = 0; i < nodes.length; i += 1) {
-		const node = nodes[i];
-		if (Array.isArray(node)) {
-			flatten(node, target);
-		} else {
-			target.push(node);
-		}
-	}
-
-	return target;
+	return { js: flatten(body), css };
 }

src/compiler/compile/utils/extract_svelte_ignore.ts

@@ -0,0 +1,12 @@
+import { flatten } from "./flatten";
+
+const pattern = /^\s*svelte-ignore\s+([\s\S]+)\s*$/m;
+
+export function extract_svelte_ignore(text: string): string[] {
+	const match = pattern.exec(text);
+	return match ? match[1].split(/[^\S]/).map(x => x.trim()).filter(Boolean) : [];
+}
+
+export function extract_svelte_ignore_from_comments<Node extends { leadingComments?: Array<{value: string}> }>(node: Node): string[] {
+	return flatten((node.leadingComments || []).map(comment => extract_svelte_ignore(comment.value)));
+}

src/compiler/compile/utils/flatten.ts

@@ -0,0 +1,14 @@
+export function flatten<T>(nodes: T[][], target?: T[]): T[];
+export function flatten<T>(nodes: T[], target?: T[]): T[];
+export function flatten(nodes: any[], target: any[] = []): any[] {
+	for (let i = 0; i < nodes.length; i += 1) {
+		const node = nodes[i];
+		if (Array.isArray(node)) {
+			flatten(node, target);
+		} else {
+			target.push(node);
+		}
+	}
+
+	return target;
+}

test/validator/samples/silence-warnings.solo/input.svelte

@@ -0,0 +1,15 @@
+<script context="module">
+	let foo;
+</script>
+
+<script>
+	// svelte-ignore unused-export-let
+	export let unused;
+	// svelte-ignore module-script-reactive-declaration
+	$: reactive = foo;
+</script>
+
+<!-- svelte-ignore css-unused-selector -->
+<style>
+	.unused {}
+</style>

test/validator/samples/silence-warnings.solo/warnings.json

@@ -0,0 +1 @@
+[]