Some errors reported by javac have the "NON_DEFERRABLE" flag, which means the error should not be stored in `DeferredDiagnosticHandler`, but rather should be reported immediately.

This is particularly the case when e.g. entering the sources before annotation processing - the errors are not reported to the user immediately, as they may be resolved by the AP. Hence ordinary errors are stored in `DeferredDiagnosticHandler` and reported later if needed. Non-deferrable errors are not stored, but reported immediately, as those are typically serious errors that cannot be fixed by AP.

javac also has an `Analyzer`, which looks for code simplifications by speculatively simplifying the code, and re-attributing it to see if it would still compile. It is using `DeferredDiagnosticHandler`, so that if any errors are found during the speculative attribution, the code simplification is rejected.

But, if a non-deferrable error is reported during the speculative attribution, it is passed through `DeferredDiagnosticHandler` undetected, and the `Analyzer` may try to do further evaluations - which may crash the compiler.

See the attached jtreg test. It fails with:
---
An exception has occurred in the compiler (25-internal). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
java.lang.AssertionError: Analyzer error when processing: Utils.run(new Task<Param>(){
    
    () {
        super();
    }
    
    @Override
    public void run(Param parameter) throws Exception {
    }
});:java.lang.NullPointerException: Cannot invoke "com.sun.tools.javac.code.Type.getTypeArguments()" because "com.sun.tools.javac.util.List.get(int).type" is null
jdk.compiler/com.sun.tools.javac.comp.Analyzer$DiamondInitializer.process(Analyzer.java:258)
jdk.compiler/com.sun.tools.javac.comp.Analyzer$DiamondInitializer.process(Analyzer.java:228)
jdk.compiler/com.sun.tools.javac.comp.Analyzer.doAnalysis(Analyzer.java:577)
jdk.compiler/com.sun.tools.javac.comp.Analyzer$2.flush(Analyzer.java:547)
jdk.compiler/com.sun.tools.javac.comp.Analyzer.flush(Analyzer.java:591)
jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1427)
jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1395)
jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:983)
jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)
jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
toolbox.JavacTask.runAPI(JavacTask.java:420)
toolbox.JavacTask.run(JavacTask.java:359)
toolbox.AbstractTask.run(AbstractTask.java:102)
toolbox.JavacTask.run(JavacTask.java:52)
toolbox.JavacTask.run(JavacTask.java:321)
Diamond.testUndefinedConstructorParam(Diamond.java:126)
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
java.base/java.lang.reflect.Method.invoke(Method.java:565)
toolbox.TestRunner.runTests(TestRunner.java:91)
Diamond.runTests(Diamond.java:61)
Diamond.main(Diamond.java:52)
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
java.base/java.lang.reflect.Method.invoke(Method.java:565)
com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
java.base/java.lang.Thread.run(Thread.java:1447)
at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:162)
at jdk.compiler/com.sun.tools.javac.comp.Analyzer.doAnalysis(Analyzer.java:579)
at jdk.compiler/com.sun.tools.javac.comp.Analyzer$2.flush(Analyzer.java:547)
at jdk.compiler/com.sun.tools.javac.comp.Analyzer.flush(Analyzer.java:591)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1427)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1395)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:983)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
at toolbox.JavacTask.runAPI(JavacTask.java:420)
at toolbox.JavacTask.run(JavacTask.java:359)
at toolbox.AbstractTask.run(AbstractTask.java:102)
at toolbox.JavacTask.run(JavacTask.java:52)
at toolbox.JavacTask.run(JavacTask.java:321)
at Diamond.testUndefinedConstructorParam(Diamond.java:126)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at toolbox.TestRunner.runTests(TestRunner.java:91)
at Diamond.runTests(Diamond.java:61)
at Diamond.main(Diamond.java:52)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at java.base/java.lang.Thread.run(Thread.java:1447)
---