NPE in org.eclipse.jdt.internal.compiler.ast.MessageSend.analyseCode

[stephan-herrmann]

fixes #1621

What it does

Fix resolving of a synthetic lambda representing a reference expression which depends on a pattern variable.

This resolving was broken, because the synthetic lambda AST has no information about the syntactic context which may declare pattern variables depending on flow.

This is fixed by temporarily resetting AccPatternVariable just like done in Statement.resolveWithPatternVariablesInScope().

[stephan-herrmann]

@jarthana FYI. Yes, Statement.resolveWithPatternVariablesInScope() is a powerful concept, but unfortunately it must be repeated for any synthetic AST (is there more of this kind lurking under the rug?).

[iloveeclipse]

@stephan-herrmann : master is not open yet, please don't merge until official announcement

[stephan-herrmann]

@stephan-herrmann : master is not open yet, please don't merge until official announcement

I'm sorry, I saw that R4_30_maintenance has been created and the freeze period check signaled OK (to my surprise actually). Also eclipse-dev gave no indication of a freeze at this point.

Feel free to revert, should a RC2a be needed.