Issue an warning when compiling a template that do not match an structural directive selector.

Relevant Package

This feature request is for @angular/core

Description

The compiler completely ignore an selector like *myStructuralDirective without warning if it do not match any directive. This turns difficult to see that we are doing something wrong.

Describe the solution you'd like

If the selector in the template for an structural directive do not match any directive, show an warning about possible wrong usage.

Describe alternatives you've considered

I don't see alternatives.