Max call stack size exceeded for class expression with extends clause in static method

[FabianLauer]

TypeScript Version: 2.7.0-dev.201xxxxx

Code

// test.ts
export class Test {
	public static createSubclass() {
		return class extends Test { };
	}
}

Expected behavior:
TSC should not fail to compile with --declaration.

Actual behavior:
TSC fails with Maximum call stack size exceeded:

> tsc --declaration test.ts                                                                                                                                                                                                                 

/usr/local/lib/node_modules/typescript/lib/tsc.js:59538
                throw e;
                ^

RangeError: Maximum call stack size exceeded
    at writeKeyword (/usr/local/lib/node_modules/typescript/lib/tsc.js:21320:30)
    at buildSignatureDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22591:21)
    at writeObjectLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:22366:25)
    at writeLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:22352:21)
    at writeAnonymousType (/usr/local/lib/node_modules/typescript/lib/tsc.js:22246:33)
    at writeType (/usr/local/lib/node_modules/typescript/lib/tsc.js:22098:25)
    at buildTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22061:24)
    at buildReturnTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22586:21)
    at buildSignatureDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22601:17)
    at writeObjectLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:22388:33)

More Details:

Seems like the error is not caused by extending the specific class that owns the static method, but it also fails with other bases:

// fails too:

export class Foo { }

export class Test {
	public static createSubclass() {
		return class extends Foo { };
	}
}

When the class expression is returned by an instance method though, TSC does not fail:

// works:
export class Test {
	public createSubclass() {
		return class extends Test { };
	}
}

// result:
export declare class Test {
    createSubclass(): {
        new (): {
            createSubclass(): any;
        };
    };
}

[FabianLauer]

Just noticed that my first example also fails with TSC version 2.6.2, both with --declaration and --watch.

tsc --declaration test.ts

/usr/local/lib/node_modules/typescript/lib/tsc.js:58192
                throw e;
                ^

RangeError: Maximum call stack size exceeded
    at writeTypeReference (/usr/local/lib/node_modules/typescript/lib/tsc.js:21698:44)
    at writeType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21617:25)
    at buildTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:21602:24)
    at buildReturnTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22109:21)
    at buildSignatureDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22124:17)
    at writeObjectLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21890:25)
    at writeLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21876:21)
    at writeAnonymousType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21777:33)
    at writeType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21639:25)
    at buildTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:21602:24)

tsc -w test.ts

/usr/local/lib/node_modules/typescript/lib/tsc.js:58192
                throw e;
                ^

RangeError: Maximum call stack size exceeded
    at writeKeyword (/usr/local/lib/node_modules/typescript/lib/tsc.js:20867:30)
    at buildSignatureDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22114:21)
    at writeObjectLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21890:25)
    at writeLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21876:21)
    at writeAnonymousType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21777:33)
    at writeType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21639:25)
    at buildTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:21602:24)
    at buildReturnTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22109:21)
    at buildSignatureDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22124:17)
    at writeObjectLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21912:33)

tsc -w --declaration test.ts

/usr/local/lib/node_modules/typescript/lib/tsc.js:58192
                throw e;
                ^

RangeError: Maximum call stack size exceeded
    at getIndentString (/usr/local/lib/node_modules/typescript/lib/tsc.js:7546:29)
    at Object.write (/usr/local/lib/node_modules/typescript/lib/tsc.js:7566:31)
    at writeKeyword (/usr/local/lib/node_modules/typescript/lib/tsc.js:20868:20)
    at buildSignatureDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22114:21)
    at writeObjectLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21890:25)
    at writeLiteralType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21876:21)
    at writeAnonymousType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21777:33)
    at writeType (/usr/local/lib/node_modules/typescript/lib/tsc.js:21639:25)
    at buildTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:21602:24)
    at buildReturnTypeDisplay (/usr/local/lib/node_modules/typescript/lib/tsc.js:22109:21)

[sandersn]

The loop happens when trying to turn the static type of class extends C {} into a type node that can be printed. typeToTypeNode should probably cut off the return type with any:

class C 
{ 
    make(): { 
        new(): { }; 
        make(): any 
    }
}

But it doesn't. I'll need to investigate further to find out how similar cutoffs work; it's a while since I looked at this code. @weswigham have you touched this recently? If so, can you point me in the right direction?

[weswigham]

@sandersn we have a flag that causes us to attempt to write the structure of the class (for handling, eg, mixins (like this)), and the second example isn't even self-referential, so in theory it should print structurally just fine.

[mhegazy]

Should be fixed by #24225