Many NPE when hover or refactor inside "instanceof" block

[jukzi]

package p;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

public class Test {
	{
		Map<String,Collection<Object>> binaryLocationsJars=new HashMap<>();
		if (null instanceof Object jar) {
				binaryLocationsJars.compute("", (pp,me // hover "me", or refactor "me"
						) ->{
					return me;
				});
		}
	}
}

for example

java.lang.NullPointerException: Cannot invoke "org.eclipse.jdt.internal.compiler.lookup.TypeBinding.signableName()" because "binding.type" is null
	at org.eclipse.jdt.internal.core.SelectionRequestor.acceptLocalVariable(SelectionRequestor.java:418)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.selectFrom(SelectionEngine.java:1351)
	at org.eclipse.jdt.internal.codeassist.SelectionEngine.select(SelectionEngine.java:1041)
	at org.eclipse.jdt.internal.core.Openable.codeSelect(Openable.java:167)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:403)
	at org.eclipse.jdt.internal.core.CompilationUnit.codeSelect(CompilationUnit.java:393)
	at org.eclipse.jdt.internal.debug.ui.JavaDebugHover.resolveElement(JavaDebugHover.java:519)
	at org.eclipse.jdt.internal.debug.ui.JavaDebugHover.getHoverInfo2(JavaDebugHover.java:302)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:163)
	at org.eclipse.jdt.internal.ui.text.java.hover.BestMatchHover.getHoverInfo2(BestMatchHover.java:130)
	at org.eclipse.jdt.internal.ui.text.java.hover.JavaEditorTextHoverProxy.getHoverInfo2(JavaEditorTextHoverProxy.java:89)
	at org.eclipse.jface.text.TextViewerHoverManager$1.run(TextViewerHoverManager.java:155)

[srikanth-sankaran]

Thanks @jukzi - I'll take a look - Since this is tagged as a regression, do you know the last version where this worked ?

[jukzi]

Sorry, don't know. Don't even proofed it ever worked. "regression" is only a guess in this case because i can not remember to ever had a problem there.

[jukzi]

Still an issue! Refactoring (ALT+SHIFT+R) "me" became even worse, now logging tons of Exceptions:

[srikanth-sankaran]

The recovered parse tree is:

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
public class Test {
  {
    Map<String, Collection<Object>> binaryLocationsJars;
    {
      <SelectionOnArgumentName:me>;
    }
  }
  public Test() {
  }
}

We don't even recognize me to be a lambda parameter. So the elided type of the local is unresolved and null resulting in NPE.

[srikanth-sankaran]

Sorry, don't know. Don't even proofed it ever worked. "regression" is only a guess in this case because i can not remember to ever had a problem there.

A random pick of 4.20 shows we don't NPE there, so it is a regression although I don't know exactly since when

[srikanth-sankaran]

This is likely a bit involved, I will revisit when I have time ...