Backslash u in a comment produces a weird parser error

If we include backslash u as comment in a script (without being a correct unicode escape sequence), we get no compiler error, just a warning at the top of the class/script with the stacktrace [1]. The class/script is not properly compiled and cannot be referenced from other classes/scripts. The error is very difficult to diagnose, since we have no precise location of the problem in the script and even no precise problem description from the compiler.

The example of such a script is the following:

// hello \u
class Foo{}

Note 1: this problem is particularly tacky, since '\u' sequences can occur 'naturally' as part of pasting windows paths within comments

Note 2: java does not allow an incomplete unicode escape sequence either, but mark such an occurence with a compile time error, the problematic location underlined in red and the error message 'Invalid unicode'. I would expect the Groovy editor to do the same.

[1] Stacktrace shown as warning at the top of the class

antlr.TokenStreamIOException: Did not find four digit hex character code. line: 3 col:9
at org.codehaus.groovy.internal.antlr.parser.GroovyLexer.nextToken(GroovyLexer.java:710)
at org.codehaus.groovy.internal.antlr.parser.GroovyLexer$1.nextToken(GroovyLexer.java:249)
at antlr.TokenBuffer.fill(TokenBuffer.java:69)
at antlr.TokenBuffer.LA(TokenBuffer.java:80)
at antlr.LLkParser.LA(LLkParser.java:52)
at org.codehaus.groovy.internal.antlr.parser.GroovyRecognizer.identifier(GroovyRecognizer.java:1740)
at org.codehaus.groovy.internal.antlr.parser.GroovyRecognizer.packageDefinition(GroovyRecognizer.java:941)
at org.codehaus.groovy.internal.antlr.parser.GroovyRecognizer.compilationUnit(GroovyRecognizer.java:686)
at org.codehaus.groovy.antlr.ErrorRecoveredCSTParserPlugin.transformCSTIntoAST(ErrorRecoveredCSTParserPlugin.java:62)
at org.codehaus.groovy.antlr.AntlrParserPlugin.parseCST(AntlrParserPlugin.java:79)
at org.codehaus.groovy.control.SourceUnit.parse(SourceUnit.java:260)
at org.codehaus.groovy.control.CompilationUnit$8.call(CompilationUnit.java:179)
at org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:943)
at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:574)
at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:550)
at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:527)
at org.codehaus.jdt.groovy.internal.compiler.ast.GroovyCompilationUnitDeclaration.processToPhase(GroovyCompilationUnitDeclaration.java:165)
at org.codehaus.jdt.groovy.internal.compiler.ast.GroovyParser.dietParse(GroovyParser.java:309)
at org.codehaus.jdt.groovy.integration.internal.MultiplexingCommentRecorderParser.dietParse(MultiplexingCommentRecorderParser.java:60)
at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:159)
at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.buildCompilationUnit(SourceTypeConverter.java:121)
at org.eclipse.jdt.internal.core.hierarchy.HierarchyResolver.resolve(HierarchyResolver.java:698)
at org.eclipse.jdt.internal.core.hierarchy.HierarchyResolver.resolve(HierarchyResolver.java:613)
at org.eclipse.jdt.internal.core.hierarchy.HierarchyBuilder.buildSupertypes(HierarchyBuilder.java:125)
at org.eclipse.jdt.internal.core.hierarchy.IndexBasedHierarchyBuilder.build(IndexBasedHierarchyBuilder.java:135)
at org.eclipse.jdt.internal.core.hierarchy.TypeHierarchy.compute(TypeHierarchy.java:300)
at org.eclipse.jdt.internal.core.hierarchy.TypeHierarchy.refresh(TypeHierarchy.java:1263)
at org.eclipse.jdt.internal.core.CreateTypeHierarchyOperation.executeOperation(CreateTypeHierarchyOperation.java:90)
at org.eclipse.jdt.internal.core.JavaModelOperation.run(JavaModelOperation.java:728)
at org.eclipse.jdt.internal.core.JavaModelOperation.runOperation(JavaModelOperation.java:788)
at org.eclipse.jdt.internal.core.SourceType.newSupertypeHierarchy(SourceType.java:726)
at org.eclipse.jdt.internal.core.SourceType.newSupertypeHierarchy(SourceType.java:678)
at org.eclipse.jdt.internal.junit.util.CoreTestSearchEngine.isTestImplementor(CoreTestSearchEngine.java:115)
at org.eclipse.jdt.internal.junit.launcher.JUnit3TestFinder.isTestImplementor(JUnit3TestFinder.java:91)
at org.eclipse.jdt.internal.junit.launcher.JUnit3TestFinder.isTest(JUnit3TestFinder.java:87)
at org.eclipse.jdt.internal.junit.util.CoreTestSearchEngine.isTestOrTestSuite(CoreTestSearchEngine.java:54)
at org.eclipse.jdt.internal.junit.JUnitPropertyTester.isJUnitTest(JUnitPropertyTester.java:113)
at org.eclipse.jdt.internal.junit.JUnitPropertyTester.canLaunchAsJUnitTest(JUnitPropertyTester.java:88)
at org.eclipse.jdt.internal.junit.JUnitPropertyTester.test(JUnitPropertyTester.java:71)
at org.eclipse.core.internal.expressions.Property.test(Property.java:58)
at org.eclipse.core.internal.expressions.TestExpression.evaluate(TestExpression.java:99)
at org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:53)
at org.eclipse.core.internal.expressions.AdaptExpression.evaluate(AdaptExpression.java:91)
at org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:53)
at org.eclipse.core.internal.expressions.IterateExpression.evaluate(IterateExpression.java:150)
at org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:53)
at org.eclipse.core.internal.expressions.WithExpression.evaluate(WithExpression.java:72)
at org.eclipse.core.internal.expressions.CompositeExpression.evaluateAnd(CompositeExpression.java:53)
at org.eclipse.core.internal.expressions.EnablementExpression.evaluate(EnablementExpression.java:53)
at org.eclipse.debug.internal.ui.launchConfigurations.LaunchShortcutExtension.evalEnablementExpression(LaunchShortcutExtension.java:287)
at org.eclipse.debug.internal.ui.launchConfigurations.LaunchConfigurationManager.getApplicableConfigurationTypes(LaunchConfigurationManager
.java:744)
at org.eclipse.debug.internal.ui.launchConfigurations.LaunchConfigurationManager.getApplicableLaunchConfigurations(LaunchConfigurationManag
er.java:780)
at org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager.getParticipatingLaunchConfigurations(LaunchingResourceManager.ja
va:506)
at org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager.getLabel(LaunchingResourceManager.java:320)
at org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager.computeLabels(LaunchingResourceManager.java:241)
at org.eclipse.debug.internal.ui.contextlaunching.LaunchingResourceManager$2.run(LaunchingResourceManager.java:138)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)