private static PsiType doFun(GrReferenceExpression refExpr) {
      if (ResolveUtil.isClassReference(refExpr)) {
        GrExpression qualifier = refExpr.getQualifier();
        LOG.assertTrue(qualifier != null);
        return TypesUtil.createJavaLangClassType(
            qualifier.getType(), refExpr.getProject(), refExpr.getResolveScope());
      }

      if (PsiUtil.isCompileStatic(refExpr)) {
        final GroovyResolveResult resolveResult = refExpr.advancedResolve();
        final PsiElement resolvedF = resolveResult.getElement();
        final PsiType type;
        if (resolvedF instanceof GrField) {
          type = ((GrField) resolvedF).getType();
        } else if (resolvedF instanceof GrAccessorMethod) {
          type = ((GrAccessorMethod) resolvedF).getProperty().getType();
        } else {
          type = null;
        }
        if (type != null) {
          return resolveResult.getSubstitutor().substitute(type);
        }
      }

      final PsiElement resolved = refExpr.resolve();
      final PsiType nominal = refExpr.getNominalType();

      Boolean reassigned = GrReassignedLocalVarsChecker.isReassignedVar(refExpr);
      if (reassigned != null && reassigned.booleanValue()) {
        return GrReassignedLocalVarsChecker.getReassignedVarType(refExpr, true);
      }

      final PsiType inferred = getInferredTypes(refExpr, resolved);
      if (inferred == null) {
        if (nominal == null) {
          // inside nested closure we could still try to infer from variable initializer. Not sound,
          // but makes sense
          if (resolved instanceof GrVariable) {
            LOG.assertTrue(resolved.isValid());
            return ((GrVariable) resolved).getTypeGroovy();
          }
        }

        return nominal;
      }

      if (nominal == null) return inferred;
      if (!TypeConversionUtil.isAssignable(TypeConversionUtil.erasure(nominal), inferred, false)) {
        if (resolved instanceof GrVariable
            && ((GrVariable) resolved).getTypeElementGroovy() != null) {
          return nominal;
        }
      }
      return inferred;
    }