Support implicit type coercion errors in es5-shim

src/ast/nodes/BinaryExpression.ts

@@ -1,7 +1,11 @@
 import { DeoptimizableEntity } from '../DeoptimizableEntity';
 import { ExecutionPathOptions } from '../ExecutionPathOptions';
-import { ImmutableEntityPathTracker } from '../utils/ImmutableEntityPathTracker';
+import {
+	EMPTY_IMMUTABLE_TRACKER,
+	ImmutableEntityPathTracker
+} from '../utils/ImmutableEntityPathTracker';
 import { EMPTY_PATH, LiteralValueOrUnknown, ObjectPath, UNKNOWN_VALUE } from '../values';
+import ExpressionStatement from './ExpressionStatement';
 import { LiteralValue } from './Literal';
 import * as NodeType from './NodeType';
 import { ExpressionNode, NodeBase } from './shared/Node';
@@ -36,12 +40,14 @@ const binaryOperators: {
 	'|': (left: any, right: any) => left | right
 };
 
-export default class BinaryExpression extends NodeBase {
+export default class BinaryExpression extends NodeBase implements DeoptimizableEntity {
 	left!: ExpressionNode;
 	operator!: keyof typeof binaryOperators;
 	right!: ExpressionNode;
 	type!: NodeType.tBinaryExpression;
 
+	deoptimizeCache(): void {}
+
 	getLiteralValueAtPath(
 		path: ObjectPath,
 		recursionTracker: ImmutableEntityPathTracker,
@@ -60,6 +66,18 @@ export default class BinaryExpression extends NodeBase {
 		return operatorFn(leftValue as LiteralValue, rightValue as LiteralValue);
 	}
 
+	hasEffects(options: ExecutionPathOptions): boolean {
+		// support some implicit type coercion runtime errors
+		if (
+			this.operator === '+' &&
+			this.parent instanceof ExpressionStatement &&
+			this.left.getLiteralValueAtPath(EMPTY_PATH, EMPTY_IMMUTABLE_TRACKER, this) === ''
+		) {
+			return true;
+		}
+		return super.hasEffects(options);
+	}
+
 	hasEffectsWhenAccessedAtPath(path: ObjectPath, _options: ExecutionPathOptions) {
 		return path.length > 1;
 	}

test/form/samples/deopt-string-concatenation/_config.js

@@ -0,0 +1,4 @@
+module.exports = {
+	description:
+		'deoptimize concatenation when used as an expression statement to better support es5-shim'
+};

test/form/samples/deopt-string-concatenation/_expected.js

@@ -0,0 +1,11 @@
+function parseInt(str, radix) {
+	if (typeof str === 'symbol') {
+		'' + str;
+	}
+
+	var string = trim(String(str));
+	var defaultedRadix = $Number(radix) || (hexRegex.test(string) ? 16 : 10);
+	return origParseInt(string, defaultedRadix);
+}
+
+console.log(parseInt('1'));

test/form/samples/deopt-string-concatenation/main.js

@@ -0,0 +1,11 @@
+function parseInt(str, radix) {
+	if (typeof str === 'symbol') {
+		'' + str;
+	}
+
+	var string = trim(String(str));
+	var defaultedRadix = $Number(radix) || (hexRegex.test(string) ? 16 : 10);
+	return origParseInt(string, defaultedRadix);
+}
+
+console.log(parseInt('1'));