Grammar checking errors should be reported during binding phases instead of type-checking phase

[dbaeumer]

From @StrongRef on December 15, 2015 9:32

When declaring an octal literal, an error is shown.

However, if another error is introduced, the error for octal literal usage is omitted.

Another strict rule violation, this time both errors are visible.

I could like into this one, just want to make sure this is an actual error.

Copied from original issue: microsoft/vscode#1318

[dbaeumer]

This is the tsserver. Moving to TS.

[yuit]

@dbaeumer @StrongRef so here is what happen in these situation. Compilers can have error from different states : parsing, binding, type-checking (this include grammar errors), and emitting phases.The compiler will not report grammar error during typ-checking(e.g "Octal Literals are not available when targeting ECMAScript5 and higher") if there are a parsing errors (e.g from doing 1.foo). However, binding error (e.g the one from ...{p:1, p:2}) will be reported regarding less of parsing errors. The main reason of such behavior is to prevent cascading errors effect.

Arguably, it may be the case taht we should move the grammar checking phase from type-checking phase into binding phase. @CyrusNajmabadi can weight-in more.

[mhegazy]

should be covered by #6802