Function SubstituteTemplateType

src/function/function_binder.cpp:565–584

}

static void SubstituteTemplateType(LogicalType &type, case_insensitive_map_t<vector<LogicalType>> &bindings,
                                   const string &function_name) {
	// Replace all template types in with their bound concrete types.
	type = TypeVisitor::VisitReplace(type, [&](const LogicalType &t) -> LogicalType {
		if (t.id() == LogicalTypeId::TEMPLATE) {
			const auto index = TemplateType::GetName(t);
			auto it = bindings.find(index);
			if (it != bindings.end()) {
				// found a binding, return the concrete type
				return LogicalType::NormalizeType(it->second.back());
			}

			// If we reach here, the template type was not bound to any concrete type.
			// We dont throw an error here, but give users a chance to handle unresolved template type later in the
			// "bind_scalar_function_t" callback. We then throw an error if the template type is still not bound
			// in the "CheckTemplateTypesResolved" method afterwards.
		}
		return t;
	});
}

void FunctionBinder::ResolveTemplateTypes(BaseScalarFunction &bound_function,
                                          const vector<unique_ptr<Expression>> &children) {