Runtime error in Eclipse about abstools HOT 2 CLOSED

java.lang.RuntimeException: Trying to evaluate attribute in subtree not attached to main tree
    at abs.frontend.ast.CompilationUnit.lookupModule(CompilationUnit.java:1298)
    at abs.frontend.ast.CompilationUnit.Define_ModuleDecl_lookupModule(CompilationUnit.java:1354)
    at abs.frontend.ast.ASTNode.Define_ModuleDecl_lookupModule(ASTNode.java:1662)
    at abs.frontend.ast.ModuleDecl.lookupModule(ModuleDecl.java:1515)
    at abs.frontend.typechecker.TypeCheckerHelper.getImportedNames(TypeCheckerHelper.java:279)
    at abs.frontend.ast.ModuleDecl.getImportedNames_compute(ModuleDecl.java:1280)
    at abs.frontend.ast.ModuleDecl.getImportedNames(ModuleDecl.java:1267)
    at abs.frontend.typechecker.TypeCheckerHelper.getVisibleNames(TypeCheckerHelper.java:310)
    at abs.frontend.ast.ModuleDecl.getVisibleNames_compute(ModuleDecl.java:1088)
    at abs.frontend.ast.ModuleDecl.getVisibleNames(ModuleDecl.java:1075)
    at abs.frontend.ast.ModuleDecl.resolveName(ModuleDecl.java:385)
    at abs.frontend.ast.ModuleDecl.lookup_compute(ModuleDecl.java:1494)
    at abs.frontend.ast.ModuleDecl.lookup(ModuleDecl.java:1481)
    at abs.frontend.ast.ModuleDecl.Define_Decl_lookup(ModuleDecl.java:1604)
    at abs.frontend.ast.ASTNode.Define_Decl_lookup(ASTNode.java:1669)
    at abs.frontend.ast.ASTNode.Define_Decl_lookup(ASTNode.java:1669)
    at abs.frontend.ast.ASTNode.Define_Decl_lookup(ASTNode.java:1669)
    at abs.frontend.ast.ASTNode.Define_Decl_lookup(ASTNode.java:1669)
    at abs.frontend.ast.DataTypeUse.lookup(DataTypeUse.java:401)
    at abs.frontend.ast.ParametricDataTypeUse.Define_Decl_lookup(ParametricDataTypeUse.java:550)
    at abs.frontend.ast.ASTNode.Define_Decl_lookup(ASTNode.java:1669)
    at abs.frontend.ast.Exp.lookup(Exp.java:438)
    at abs.frontend.ast.TypeUse.getDecl_compute(TypeUse.java:393)
    at abs.frontend.ast.TypeUse.getDecl(TypeUse.java:381)
    at abs.frontend.ast.UnresolvedTypeUse.rewriteTo(UnresolvedTypeUse.java:365)
    at abs.frontend.ast.ASTNode.getChild(ASTNode.java:606)
    at abs.frontend.ast.List.rewriteTo(List.java:287)
    at abs.frontend.ast.ASTNode.getChild(ASTNode.java:606)
    at abs.frontend.parser.SourcePosition.findPosition(SourcePosition.java:43)