Clang-tidy right side const qualification

Clang Frontend clang-tidy
1

I’m trying to implement a clang-tidy check to warn about the use of output parameters.

As registerMatchers method, I have the following:

void AvoidouputparametersCheck::registerMatchers(MatchFinder *Finder) {
    Finder->addMatcher(
	      functionDecl(isDefinition(), hasBody(stmt()), hasAnyParameter(decl())).bind("function"),
	      this);
}

As check method, I have the following:

void AvoidouputparametersCheck::check(const MatchFinder::MatchResult &Result) {
    const auto *Function = Result.Nodes.getNodeAs<FunctionDecl>("function");
	for (unsigned i = 0, e = Function->getNumParams(); i != e; ++i) {
	    const auto *Param = Function->getParamDecl(i);
		if(!Param->getType().getCanonicalType().isConstQualified() && Param->getType().getTypePtr 
        ()->isReferenceType())
			 auto MyDiag = diag(Param->getLocation(), "avoid output parameters") << Param;
	}

If I run clang-tidy I have the following warnings:

void foo(int a &){} warning: output parameter

void foo(const int &a){}

void foo(int const &a){} warning: output parameter

When I place const in the right hand side of the type, clang does not detect it as a const qualified parameters.