Support TypeScript 3.0

[evmar]

With TypeScript 3.0.0-rc, below failures.

Apparently it's now possible for Nodes to not have any tokens, which I'm not sure how to fix.
The other issues look minor, just some adjusted signatures.

test/rules/control-flow/testCfaRule.ts:32:34 - error TS2345: Argument of type 'Node | undefined' is not assignable to parameter of type 'Node'.
  Type 'undefined' is not assignable to type 'Node'.

32             ctx.addFailureAtNode(node.getFirstToken(ctx.sourceFile), 'control flow end');
                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

test/tokenTests.ts:67:45 - error TS2345: Argument of type 'Node | undefined' is not assignable to parameter of type 'Node'.
  Type 'undefined' is not assignable to type 'Node'.

67         assert.isUndefined(getPreviousToken(sourceFile.getFirstToken()), 'Token');
                                               ~~~~~~~~~~~~~~~~~~~~~~~~~~

util/type.ts:87:5 - error TS2322: Type 'ReadonlyArray<Signature>' is not assignable to type 'Signature[]'.
  Property 'push' is missing in type 'ReadonlyArray<Signature>'.

87     return type.getCallSignatures();
       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

util/type.ts:97:61 - error TS2345: Argument of type 'Type | undefined' is not assignable to parameter of type 'Type'.
  Type 'undefined' is not assignable to type 'Type'.

97     for (const ty of unionTypeParts(checker.getApparentType(type))) {
                                                               ~~~~

util/util.ts:85:41 - error TS2345: Argument of type 'Node' is not assignable to parameter of type 'Declaration'.
  Property '_declarationBrand' is missing in type 'Node'.

85     return (ts.getCombinedModifierFlags(node) & flag) !== 0;
                                           ~~~~

util/util.ts:953:15 - error TS2339: Property 'unescapeIdentifier' does not exist on type 'typeof ts'.

953     return ts.unescapeIdentifier ? ts.unescapeIdentifier(node.text) : node.text;
                  ~~~~~~~~~~~~~~~~~~

util/util.ts:953:39 - error TS2339: Property 'unescapeIdentifier' does not exist on type 'typeof ts'.

953     return ts.unescapeIdentifier ? ts.unescapeIdentifier(node.text) : node.text;
                                          ~~~~~~~~~~~~~~~~~~

[ajafff]

IIUC this is not a problem with the library but only occurs when building with a newer TypeScript version?

Regarding "Nodes to not have any tokens": this was possible before. Not the type declarations are just more correct. The cases above can simply be asserted to never be undefined.
That Type | undefined can also be asserted.

ReadonlyArray<Signature> not assignable to Signature[] probably just needs to fix the return type of the containing function.

The (un)escapeIdentifier functions needs an assertion to any.

---

If you want to fix this, feel free to send a PR. Otherwise I'll try to get this fixed tomorrow.

[evmar]

These build errors are from updating the version of TypeScript in package.json. Sorry for not being clear.

I'm happy if you fix it, so I can wait. If you are too busy I can otherwise try creating a PR, but I suspect it'll be about as much work for you to review my PR as it would be to fix it directly. :)