Errors reported by ConstantEvaluationValidator should be made more specific

[srawlins]

Right now most errors use the default error, "Const variables must be initialized with a constant value." (const_initialized_with_non_constant_value). Each case can be given more information though, .e.g "constructor reference used in constant expression must be a const constructor."

[bwilkerson]

Yes, and many of them should have context messages associated with them. I took a look at this a couple of years ago but didn't have time for the amount of work that I thought would be necessary. Happy to discuss if you're interested.

[asashour]

The only usage I see is

sdk/pkg/analyzer/lib/src/dart/constant/constant_verifier.dart

Lines 249 to 250 in a6cc772

	_reportErrors(result.errors,
	CompileTimeErrorCode.CONST_INITIALIZED_WITH_NON_CONSTANT_VALUE);

This is a new area for me, but am interested to help, hope further requirements are specified.