Add missing spaces in certain statements and expressions to avoid inv…

…alid code (#3173)

* Add missing spaces in certain statements and expressions to avoid invalid syntax

* Improve coverage

src/ast/nodes/AwaitExpression.ts

@@ -1,5 +1,3 @@
-import MagicString from 'magic-string';
-import { RenderOptions } from '../../utils/renderHelpers';
 import { HasEffectsContext, InclusionContext } from '../ExecutionContext';
 import ArrowFunctionExpression from './ArrowFunctionExpression';
 import * as NodeType from './NodeType';
@@ -11,22 +9,21 @@ export default class AwaitExpression extends NodeBase {
 	type!: NodeType.tAwaitExpression;
 
 	hasEffects(context: HasEffectsContext) {
-		return super.hasEffects(context) || !context.ignore.returnAwaitYield;
+		return !context.ignore.returnAwaitYield || this.argument.hasEffects(context);
 	}
 
 	include(context: InclusionContext, includeChildrenRecursively: IncludeChildren) {
-		checkTopLevelAwait: if (!this.included && !this.context.usesTopLevelAwait) {
-			let parent = this.parent;
-			do {
-				if (parent instanceof FunctionNode || parent instanceof ArrowFunctionExpression)
-					break checkTopLevelAwait;
-			} while ((parent = (parent as Node).parent as Node));
-			this.context.usesTopLevelAwait = true;
+		if (!this.included) {
+			this.included = true;
+			checkTopLevelAwait: if (!this.context.usesTopLevelAwait) {
+				let parent = this.parent;
+				do {
+					if (parent instanceof FunctionNode || parent instanceof ArrowFunctionExpression)
+						break checkTopLevelAwait;
+				} while ((parent = (parent as Node).parent as Node));
+				this.context.usesTopLevelAwait = true;
+			}
 		}
-		super.include(context, includeChildrenRecursively);
-	}
-
-	render(code: MagicString, options: RenderOptions) {
-		super.render(code, options);
+		this.argument.include(context, includeChildrenRecursively);
 	}
 }

src/ast/nodes/ForInStatement.ts

@@ -60,6 +60,10 @@ export default class ForInStatement extends StatementBase {
 	render(code: MagicString, options: RenderOptions) {
 		this.left.render(code, options, NO_SEMICOLON);
 		this.right.render(code, options, NO_SEMICOLON);
+		// handle no space between "in" and the right side
+		if (code.original.charCodeAt(this.right.start - 1) === 110 /* n */) {
+			code.prependLeft(this.right.start, ' ');
+		}
 		this.body.render(code, options);
 	}
 }

src/ast/nodes/ForOfStatement.ts

@@ -45,6 +45,10 @@ export default class ForOfStatement extends StatementBase {
 	render(code: MagicString, options: RenderOptions) {
 		this.left.render(code, options, NO_SEMICOLON);
 		this.right.render(code, options, NO_SEMICOLON);
+		// handle no space between "of" and the right side
+		if (code.original.charCodeAt(this.right.start - 1) === 102 /* f */) {
+			code.prependLeft(this.right.start, ' ');
+		}
 		this.body.render(code, options);
 	}
 }

src/ast/nodes/ThrowStatement.ts

@@ -20,5 +20,8 @@ export default class ThrowStatement extends StatementBase {
 
 	render(code: MagicString, options: RenderOptions) {
 		this.argument.render(code, options, { preventASI: true });
+		if (this.argument.start === this.start + 5 /* 'throw'.length */) {
+			code.prependLeft(this.start + 5, ' ');
+		}
 	}
 }

test/form/samples/side-effects-await/_config.js

@@ -1,5 +1,4 @@
 module.exports = {
 	description:
-		'await statements should never be dropped if a function has other side-effects (#1584)',
-	options: { output: { name: 'myBundle' } }
+		'await statements should never be dropped if a function has other side-effects (#1584)'
 };

test/form/samples/top-level-await/_expected/es.js

@@ -1 +1,3 @@
 await operation();
+
+await retainedOperation();

test/form/samples/top-level-await/_expected/system.js

@@ -5,6 +5,8 @@ System.register([], function () {
 
 			await operation();
 
+			await retainedOperation();
+
 		}
 	};
 });

test/form/samples/top-level-await/main.js

@@ -1,4 +1,4 @@
 await operation();
 
-if (false)
-	await treeshakenOperation();
+if (false) await treeshakenOperation();
+else await retainedOperation();

test/function/samples/missing-spaces-after-simplification/_config.js

@@ -0,0 +1,5 @@
+module.exports = {
+	description:
+		'handle situations where the simplification of an expression can lead to issues due to missing white-space',
+	options: { treeshake: { tryCatchDeoptimization: false } }
+};

test/function/samples/missing-spaces-after-simplification/main.js

@@ -0,0 +1,28 @@
+let result = '';
+
+const a = { a: true };
+for (const key in!0?a:a) result += key;
+
+const b = ['b'];
+for (const value of!0?b:b) result += value;
+
+const c = 'c';
+function testReturn() {
+	return!0?c:c;
+}
+result += testReturn();
+
+const d = 'd';
+function* testYield() {
+	yield!0?d:d;
+}
+for (const value of testYield()) result += value;
+
+const e = 'e';
+try {
+	throw!0?e:e;
+} catch (err) {
+	result += err;
+}
+
+assert.strictEqual(result, 'abcde');