Import fixes for sanitizer reported issues

See discussion in bitcoin/bitcoin#22646.

Co-authored-by: MarcoFalke <[email protected]>

Author: fanquake

lib/univalue_read.cpp

@@ -227,7 +227,7 @@ enum jtokentype getJsonToken(std::string& tokenVal, unsigned int& consumed,
             }
 
             else {
-                writer.push_back(*raw);
+                writer.push_back(static_cast<unsigned char>(*raw));
                 raw++;
             }
         }
@@ -244,7 +244,7 @@ enum jtokentype getJsonToken(std::string& tokenVal, unsigned int& consumed,
     }
 }
 
-enum expect_bits {
+enum expect_bits : unsigned {
     EXP_OBJ_NAME = (1U << 0),
     EXP_COLON = (1U << 1),
     EXP_ARR_VALUE = (1U << 2),

lib/univalue_write.cpp

@@ -13,13 +13,13 @@ static std::string json_escape(const std::string& inS)
     outS.reserve(inS.size() * 2);
 
     for (unsigned int i = 0; i < inS.size(); i++) {
-        unsigned char ch = inS[i];
+        unsigned char ch = static_cast<unsigned char>(inS[i]);
         const char *escStr = escapes[ch];
 
         if (escStr)
             outS += escStr;
         else
-            outS += ch;
+            outS += static_cast<char>(ch);
     }
 
     return outS;