Printing JS constructor function type causes out-of-memory error

[bowenni]

TypeScript Version: 3.2.2 and 3.3.0-rc

Search Terms:
heap out of memory

Code
First of all, I don't expect there to be a valid use case of what I'm describing below. In fact a miss configuration in my build settings lead me to this. However I don't expect TSC to completely crash. Also I found that TS 3.1 had no problems with the code below so this might be a regression of TS 3.2.

Steps to reproduce the heap OOM

• npm install chart.js
• cd into node_modules/chart.js/dist. You should find Chart.min.js there.
• create a tsconfig.json with the following content

{
  "compilerOptions": {
      "target": "es5",
      "module": "commonjs",
      "downlevelIteration": true,
      "skipDefaultLibCheck": true,
      "moduleResolution": "node",
      "preserveConstEnums": false,
      "experimentalDecorators": true,
      "emitDecoratorMetadata": true,
      "jsx": "react",
      "noErrorTruncation": true,
      "noEmitOnError": false,
      "declaration": false,
      "stripInternal": true,
      "inlineSourceMap": true,
      "inlineSources": true,
      "sourceMap": false,
      "jsxFactory": "react",
      "noImplicitAny": true,
      "noImplicitReturns": true,
      "noImplicitThis": true,
      "noFallthroughCasesInSwitch": true,
      "strictNullChecks": true,
      "strictPropertyInitialization": true,
      "strictFunctionTypes": true,
      "noStrictGenericChecks": true,
      "noResolve": true,
      "types": [],
      "importHelpers": false,
      "allowJs": true,
      "checkJs": false
  },
  "files": [
      "./Chart.min.js",
  ],
  "compileOnSave": false
}

• run tsc -p tsconfig.json --outDir foo and see the JavaScript heap out of memory thrown.

Expected behavior:
Emits a file foo/Chart.min.js.
TS 3.1.6 finishes this in 1.7 seconds without any errors.

Actual behavior:
FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory

Playground Link:
N/A

Related Issues:
This looks similar to #29326 and #29511 but I don't understand it deep enough to tell if it's a duplicate.

[fatcerberus]

Wow, it actually runs V8 out of heap space, that's impressive 😮

[bowenni]

I created a smaller repro in https://github.com/bowenni/heap-OOM-repro

The relevant compiler options are
"noErrorTruncation": true
"noImplicitAny": true
"allowJs": true

[sandersn]

Still crashes on 3.4 and typescript@next

[sandersn]

Also crashes with the unminified chart.js

[sandersn]

After shrinking the size of Chart.js considerably, I can see that the problem is that Color is a large class defined by prototype assignment whose methods return this. Something like this:

var Color = function (obj) {
    this.values = { rgb: [1, 1, 1] }
};

Color.prototype = {
// .........
	negate: function () {
		var rgb = [];
		for (var i = 0; i < 3; i++) {
			rgb[i] = 255 - this.values.rgb[i];
		}
		this.setValues('rgb', rgb);
		return this;
	},

	lighten: function (ratio) {
// ....

When you ask for the type of this in return this, we keep re-evaluating the type for this for each methods that returns this. The class type is not used since there is no class type created for constructor functions. Instead the class type is re-created over and over again, resulting in a factorial type structure:

this: {
  negate: () => {
    negate: any
    lighten: (ratio: any) => {
      negate: any
      lighten: any
      darken: (ratio: any) => {
        negate: any
        lighten: any
        darken: any
        greyscale: (ratio: any) => {
          negate: any
          lighten: any
          darken: any
          greyscale: any
          blacken: ...

The root cause is that constructor functions don't create classes. This type shouldn't be created over and over again, but a better fix is to make constructor functions create real classes.