Compiler error - "Maximum call stack size exceeded"

[Arnavion]

(1.5 beta)

This is the most I can reduce it while still having it crash:

class Module {
    public members: Class[];
}

class Namespace {
    public members: (Class | Property)[];
}

class Class {
    public parent: Namespace;
}

class Property {
    public parent: Module | Class;
}

var t: Class | Property;
t.toString();

tsc foo.ts -t es5

G:\src\libjass\node_modules\typescript\bin\tsc.js:0
(function (exports, require, module, __filename, __dirname) { /*! ************
^
RangeError: Maximum call stack size exceeded
    at isRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js)
    at unionTypeRelatedToType (G:\src\libjass\node_modules\typescript\bin\tsc.js:11862:35)
    at isRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11787:42)
    at stringIndexTypesRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:12195:35)
    at objectTypeRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11955:43)
    at isRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11811:34)
    at propertiesRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:12042:43)
    at objectTypeRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11949:30)
    at isRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11811:34)
    at typeRelatedToUnionType (G:\src\libjass\node_modules\typescript\bin\tsc.js:11850:35)

Alternative call stack for the crash (same code):

G:\src\libjass\node_modules\typescript\bin\tsc.js:11929
                    sourceStack = [];
                    ^
RangeError: Maximum call stack size exceeded
    at objectTypeRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11929:21)
    at isRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11811:34)
    at checkTypeRelatedTo (G:\src\libjass\node_modules\typescript\bin\tsc.js:11723:26)
    at checkTypeSubtypeOf (G:\src\libjass\node_modules\typescript\bin\tsc.js:11703:20)
    at isTypeSubtypeOf (G:\src\libjass\node_modules\typescript\bin\tsc.js:11697:20)
    at isSubtypeOfAny (G:\src\libjass\node_modules\typescript\bin\tsc.js:11363:43)
    at removeSubtypes (G:\src\libjass\node_modules\typescript\bin\tsc.js:11373:21)
    at getUnionType (G:\src\libjass\node_modules\typescript\bin\tsc.js:11410:17)
    at getReducedTypeOfUnionType (G:\src\libjass\node_modules\typescript\bin\tsc.js:11426:36)
    at getApparentType (G:\src\libjass\node_modules\typescript\bin\tsc.js:10824:24)

The original code from which this test case is derived is here.

Edit: Reduced the case some more - removed the fullName getters and simplified the types of member.

[Arnavion]

If it helps, bisect says 1d8fb49 is the first bad commit (from #2778).

[JsonFreeman]

I've identified the cause. The problem is that in a union type, we do a reduction step where we remove constituents that are subtypes of other constituents. To do that, we have to use the subtype relation, which calls checkTypeRelatedTo. But in the process of comparing union types, we have to perform subtype reduction again.

checkTypeRelatedTo has way of dealing with infinite recursion if all the infinite recursion happens inside a particular call to it. But in this case, the recursion is spread over multiple calls, and no single call is deep enough for us to catch the recursion.

The options are:

1. Pull the recursion detection out of checkTypeRelatedTo so that all calls to it share the same comparison stack.
2. Make checkTypeRelatedTo more like a class that has methods to do the comparison and locals to track the recursion.
3. Make getUnionType (which does the subtype reduction) or getReducedTypeOfUnionType detect cycles and be resilient to reentry.

I am leaning towards option 3.

[Arnavion]

I confirmed that the original code also compiles with @JsonFreeman's fix. Thanks!

[evil-shrike]

I'm experiencing this error with a source file importing a d.ts file with module aliases (via "/// <reference"). Unfortunately it's hard for me to extract what exactly causes the compiler to crash.
So let me just ask is it supposed to fail on 1.5.0-beta compiler (I mean the latest published npm package)?

With TS 1.4.1 my code is being compiled just fine.

[mhegazy]

@evil-shrike can you give the latest from branch release-1.5 a try. all you need is tsc.js and lib.d.ts from https://github.com/Microsoft/TypeScript/tree/release-1.5/bin

[evil-shrike]

@mhegazy I've tried the release-1.5 branch and got the error on it.

[mhegazy]

can you share the code sample that causes the issue?