Code review comment: I'm not sure why that was done for methods, I think it could be a different env but still a class env, we can check maybe. But, since we've been defining fields in the proper (or most relevant scope) why would be go back and define it in a less accurate (wider) scope?  The issue you are trying to solve only applies to the default value expression. I would rather we use a correct env (where the other fields are not visible, maybe somewhat similar to what was done in https://github.com/ballerina-platform/ballerina-lang/pull/35326) than change how the field itself is defined.

Code under review:
private void analyzeModuleConfigurableAmbiguity(BLangPackage pkgNode) {
        if (pkgNode.moduleContextDataHolder == null) {
            return;
        }
        ModuleDescriptor rootModule = pkgNode.moduleContextDataHolder.descriptor();
        Set<BVarSymbol> configVars = symResolver.getConfigVarSymbolsIncludingImportedModules(pkgNode.symbol);
        String rootOrgName = rootModule.org().value();
        String rootModuleName = rootModule.packageName().value();
        Map<String, PackageID> configKeys =  getModuleKeys(configVars, rootOrgName);
        for (BVarSymbol variable : configVars) {
            String moduleName = variable.pkgID.name.value;
            String orgName = variable.pkgID.orgName.value;
            String varName = variable.name.value;
            validateMapConfigVariable(orgName + "." + moduleName + "." + varName, variable, configKeys);
            if (orgName.equals(rootOrgName)) {
                validateMapConfigVariable(moduleName + "." + varName, variable, configKeys);
                if (moduleName.equals(rootModuleName) && !(varName.equals(moduleName))) {
                    validateMapConfigVariable(varName, variable, configKeys);
                }
            }
        }
    }

Line commented on: ModuleDescriptor rootModule = pkgNode.moduleContextDataHolder.descriptor();

Revised code:
private void analyzeModuleConfigurableAmbiguity(BLangPackage pkgNode) {
        if (pkgNode.moduleContextDataHolder == null) {
            return;
        }
        ModuleDescriptor rootModule = pkgNode.moduleContextDataHolder.descriptor();
        Set<BVarSymbol> configVars = symResolver.getConfigVarSymbolsIncludingImportedModules(pkgNode.symbol);
        String rootOrgName = rootModule.org().value();
        String rootModuleName = rootModule.packageName().value();
        Map<String, PackageID> configKeys =  getModuleKeys(configVars, rootOrgName);
        for (BVarSymbol variable : configVars) {
            String moduleName = variable.pkgID.name.value;
            String orgName = variable.pkgID.orgName.value;
            String varName = variable.name.value;
            validateMapConfigVariable(orgName + "." + moduleName + "." + varName, variable, configKeys);
            if (orgName.equals(rootOrgName)) {
                validateMapConfigVariable(moduleName + "." + varName, variable, configKeys);
                if (moduleName.equals(rootModuleName) && !(varName.equals(moduleName))) {
                    validateMapConfigVariable(varName, variable, configKeys);
                }
            }
        }
    }