Relax typing for comparison operators (#12537)

* Relax typing for comparison operators

Ports https://github.com/mapbox/mapbox-gl-js/pull/6961

* Review comments

* Lint fixes

1 files changed, 12 insertions, 8 deletions

diff --git a/src/mbgl/style/expression/dsl.cpp b/src/mbgl/style/expression/dsl.cpp
index a851d82e16..cdada583a2 100644
--- a/src/mbgl/style/expression/dsl.cpp
+++ b/src/mbgl/style/expression/dsl.cpp
@@ -3,7 +3,7 @@
 #include <mbgl/style/expression/literal.hpp>
 #include <mbgl/style/expression/assertion.hpp>
 #include <mbgl/style/expression/coercion.hpp>
-#include <mbgl/style/expression/equals.hpp>
+#include <mbgl/style/expression/comparison.hpp>
 #include <mbgl/style/expression/step.hpp>
 #include <mbgl/style/expression/interpolate.hpp>
 #include <mbgl/style/expression/compound_expression.hpp>
@@ -53,16 +53,20 @@ std::unique_ptr<Expression> literal(std::initializer_list<const char *> value) {
     return literal(values);
 }
 
+std::unique_ptr<Expression> assertion(type::Type type, std::unique_ptr<Expression> value) {
+    return std::make_unique<Assertion>(type, vec(std::move(value)));
+}
+
 std::unique_ptr<Expression> number(std::unique_ptr<Expression> value) {
-    return std::make_unique<Assertion>(type::Number, vec(std::move(value)));
+    return assertion(type::Number, std::move(value));
 }
 
 std::unique_ptr<Expression> string(std::unique_ptr<Expression> value) {
-    return std::make_unique<Assertion>(type::String, vec(std::move(value)));
+    return assertion(type::String, std::move(value));
 }
 
 std::unique_ptr<Expression> boolean(std::unique_ptr<Expression> value) {
-    return std::make_unique<Assertion>(type::Boolean, vec(std::move(value)));
+    return assertion(type::Boolean, std::move(value));
 }
 
 std::unique_ptr<Expression> toColor(std::unique_ptr<Expression> value) {
@@ -91,22 +95,22 @@ std::unique_ptr<Expression> zoom() {
 
 std::unique_ptr<Expression> eq(std::unique_ptr<Expression> lhs,
                                std::unique_ptr<Expression> rhs) {
-    return std::make_unique<Equals>(std::move(lhs), std::move(rhs), nullopt, false);
+    return std::make_unique<BasicComparison>("==", std::move(lhs), std::move(rhs));
 }
 
 std::unique_ptr<Expression> ne(std::unique_ptr<Expression> lhs,
                                std::unique_ptr<Expression> rhs) {
-    return std::make_unique<Equals>(std::move(lhs), std::move(rhs), nullopt, true);
+    return std::make_unique<BasicComparison>("!=", std::move(lhs), std::move(rhs));
 }
 
 std::unique_ptr<Expression> gt(std::unique_ptr<Expression> lhs,
                                std::unique_ptr<Expression> rhs) {
-    return compound(">", std::move(lhs), std::move(rhs));
+    return std::make_unique<BasicComparison>(">", std::move(lhs), std::move(rhs));
 }
 
 std::unique_ptr<Expression> lt(std::unique_ptr<Expression> lhs,
                                std::unique_ptr<Expression> rhs) {
-    return compound("<", std::move(lhs), std::move(rhs));
+    return std::make_unique<BasicComparison>("<", std::move(lhs), std::move(rhs));
 }
 
 std::unique_ptr<Expression> step(std::unique_ptr<Expression> input,