Don't enforce ["zoom"] constraints for filters (#11672)

* Don't enforce ["zoom"] constraints for filters

Fixes #11594

* Add a couple of comments

* Fix ambiguous constructor call

* ParsingContext(optional<Type>) => ParsingContext(Type)

1 files changed, 5 insertions, 2 deletions

diff --git a/src/mbgl/style/conversion/filter.cpp b/src/mbgl/style/conversion/filter.cpp
index fba149da12..3c941945fd 100644
--- a/src/mbgl/style/conversion/filter.cpp
+++ b/src/mbgl/style/conversion/filter.cpp
@@ -2,7 +2,7 @@
 #include <mbgl/util/geometry.hpp>
 #include <mbgl/style/expression/expression.hpp>
 #include <mbgl/style/expression/type.hpp>
-#include <mbgl/style/conversion/expression.hpp>
+#include <mbgl/style/expression/parsing_context.hpp>
 
 namespace mbgl {
 namespace style {
@@ -236,10 +236,13 @@ optional<Filter> convertCompoundFilter(const Convertible& value, Error& error) {
 }
     
 optional<Filter> convertExpressionFilter(const Convertible& value, Error& error) {
-    optional<std::unique_ptr<Expression>> expression = convert<std::unique_ptr<Expression>>(value, error, expression::type::Boolean);
+    expression::ParsingContext ctx(expression::type::Boolean);
+    expression::ParseResult expression = ctx.parseExpression(value);
     if (!expression) {
+        error = { ctx.getCombinedErrors() };
         return {};
     }
+
     return { ExpressionFilter { std::move(*expression) } };
 }