From G3 bug ID: 116443331
The View Engine compiler crashes when it tries to compile a test in JIT mode
that includes the d3-scale-chromatic library [1]. The d3 package initializes
some arrays using the following pattern:
```js
export var scheme = new Array(3).concat(
"d8b365f5f5f55ab4ac",
// ... more entries
).map(colors);
```
The stack trace from the crash is as follows:
```
TypeError: Cannot read property 'visitExpression' of undefined
at ../../../third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts:505:39
at JitEmitterVisitor.AbstractEmitterVisitor.visitAllObjects third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=526
at JitEmitterVisitor.AbstractEmitterVisitor.visitAllExpressions third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=505
at JitEmitterVisitor.AbstractEmitterVisitor.visitLiteralArrayExpr third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=484
at LiteralArrayExpr.visitExpression third_party/javascript/angular2/rc/packages/compiler/src/output/output_ast.ts?l=791
at ../../../third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts:492:19
at JitEmitterVisitor.AbstractEmitterVisitor.visitAllObjects third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=526
at JitEmitterVisitor.AbstractEmitterVisitor.visitLiteralMapExpr third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=490
at LiteralMapExpr.visitExpression third_party/javascript/angular2/rc/packages/compiler/src/output/output_ast.ts?l=819
at ../../../third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts:505:39
at JitEmitterVisitor.AbstractEmitterVisitor.visitAllObjects third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=526
at JitEmitterVisitor.AbstractEmitterVisitor.visitAllExpressions third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=505
at JitEmitterVisitor.AbstractEmitterVisitor.visitInvokeFunctionExpr third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_emitter.ts?l=318
at JitEmitterVisitor.AbstractJsEmitterVisitor.visitInvokeFunctionExpr third_party/javascript/angular2/rc/packages/compiler/src/output/abstract_js_emitter.ts?l=112
at InvokeFunctionExpr.visitExpression third_party/javascript/angular2/rc/packages/compiler/src/output/output_ast.ts?l=440
```
This is because the corresponding output AST for the array is of the form
```ts
[
undefined,
undefined,
undefined,
o.LiteralExpr,
// ...
]
```
The output AST is clearly malformed and breaks the type representation of
`LiteralArrayExpr` in which every entry is expected to be of type `Expression`.
This commit fixes the bug by using a plain `for` loop to iterate over the
entire length of the holey array and convert undefined elements to
`LiteralExpr`.
[1]: https://github.com/d3/d3-scale-chromatic/blob/master/src/diverging/BrBG.js
PR Close#36343
5516802142