Removed JsonVariant::as<char>() (fixes #1498)

extras/tests/FailingBuilds/CMakeLists.txt

@@ -39,3 +39,7 @@ build_should_fail(write_long_long)
 
 add_executable(delete_jsondocument delete_jsondocument.cpp)
 build_should_fail(delete_jsondocument)
+
+add_executable(variant_as_char variant_as_char.cpp)
+build_should_fail(variant_as_char)
+

extras/tests/FailingBuilds/variant_as_char.cpp

@@ -0,0 +1,12 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#include <ArduinoJson.h>
+
+// See issue #1498
+
+int main() {
+  DynamicJsonDocument doc(1024);
+  doc["dummy"].as<char>();
+}

extras/tests/JsonVariant/types.cpp

@@ -68,9 +68,6 @@ TEST_CASE("JsonVariant set()/get()") {
   SECTION("Float") {
     checkNumericType<float>();
   }
-  SECTION("Char") {
-    checkNumericType<char>();
-  }
   SECTION("SChar") {
     checkNumericType<signed char>();
   }