What compiler option "ignore_optional_problems" classpath settings maps to

[laeubi]

A classpath in JDT project can have the following entry:

<classpathentry kind="src" path=src-gen/">
        <attributes>
                <attribute name="ignore_optional_problems" value="true"/>
        </attributes>
</classpathentry>

The help page only says:

Ignore optional compile problems: When set to 'Yes', all optional problems will not be reported by the compiler.

I like to replicate the behavior in a Tycho build and wonder what are "optional problems", does it mean simply ignore all warnings like <compilerArgument>-nowarn:[${basedir}/src-gen]</compilerArgument>?

[iloveeclipse]

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=220928 and call hierarchy of org.eclipse.jdt.internal.core.ClasspathEntry.ignoreOptionalProblems().

[stephan-herrmann]

what are "optional problems"?

Problems with configurable severity, which explicitly excludes all errors mandated by JLS. Also things like build path errors can by their very nature not be ignored.