In same file as issue 88412, I am editing a method:
    public void getControlPoints (int[] xp, int[] yp) {
        xp[0] = this.x1;
        xp[1] = this.y1;
        xp[0] = this.x;
        xp[1] = y + h;
    }
At the line xp[0] = this.x I had just accepted code completion of x1.  I got
this.x and the following exception was thrown (my guess is these problems have
some connection to the fact that there are references to an undeclared variable
'x' in the file).

java.io.IOException
	at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:377)
	at
org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.query(JavaCompletionProvider.java:215)
	at
org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:195)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:541)
[catch] at
org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:963)
Caused by: java.lang.NullPointerException
	at com.sun.tools.javac.comp.Enter.getClassEnv(Enter.java:136)
	at com.sun.tools.javac.api.JavacTrees.getAttrContext(JavacTrees.java:250)
	at com.sun.tools.javac.api.JavacTrees.getScope(JavacTrees.java:184)
	at com.sun.tools.javac.api.JavacTrees.getScope(JavacTrees.java:63)
	at
org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.getCompletionEnvironment(JavaCompletionProvider.java:3216)
	at
org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.resolveCompletion(JavaCompletionProvider.java:414)
	at
org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.run(JavaCompletionProvider.java:281)
	at
org.netbeans.modules.editor.java.JavaCompletionProvider$JavaCompletionQuery.run(JavaCompletionProvider.java:81)
	at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:375)
	... 4 more