diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -26,6 +26,7 @@
 #include <cstdio>
 #include <functional>
 #include <memory>
+#include <string>
 #include <tuple>
 
 const std::function<std::string(const char *)> G_TRANSLATION_FUN = nullptr;
@@ -225,7 +226,7 @@
     std::string body;
 };
 
-static const char *http_errorstring(int code) {
+static std::string http_errorstring(int code) {
     switch (code) {
 #if LIBEVENT_VERSION_NUMBER >= 0x02010300
         case EVREQ_HTTP_TIMEOUT:
diff --git a/src/core_read.cpp b/src/core_read.cpp
--- a/src/core_read.cpp
+++ b/src/core_read.cpp
@@ -22,6 +22,7 @@
 #include <boost/algorithm/string/split.hpp>
 
 #include <algorithm>
+#include <string>
 
 CScript ParseScript(const std::string &s) {
     CScript result;
@@ -34,12 +35,11 @@
                 continue;
             }
 
-            const char *name = GetOpName(static_cast<opcodetype>(op));
-            if (strcmp(name, "OP_UNKNOWN") == 0) {
+            std::string strName = GetOpName(static_cast<opcodetype>(op));
+            if (strName == "OP_UNKNOWN") {
                 continue;
             }
 
-            std::string strName(name);
             mapOpNames[strName] = static_cast<opcodetype>(op);
             // Convenience: OP_ADD and just ADD are both recognized:
             boost::algorithm::replace_first(strName, "OP_", "");
diff --git a/src/script/script.h b/src/script/script.h
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -198,7 +198,7 @@
 // Maximum value that an opcode can be
 static const unsigned int MAX_OPCODE = FIRST_UNDEFINED_OP_VALUE - 1;
 
-const char *GetOpName(opcodetype opcode);
+std::string GetOpName(opcodetype opcode);
 
 /**
  * Check whether the given stack element data would be minimally pushed using
diff --git a/src/script/script.cpp b/src/script/script.cpp
--- a/src/script/script.cpp
+++ b/src/script/script.cpp
@@ -9,8 +9,9 @@
 #include <util/strencodings.h>
 
 #include <algorithm>
+#include <string>
 
-const char *GetOpName(opcodetype opcode) {
+std::string GetOpName(opcodetype opcode) {
     switch (opcode) {
         // push value
         case OP_0:
diff --git a/src/script/script_error.h b/src/script/script_error.h
--- a/src/script/script_error.h
+++ b/src/script/script_error.h
@@ -6,6 +6,8 @@
 #ifndef BITCOIN_SCRIPT_SCRIPT_ERROR_H
 #define BITCOIN_SCRIPT_SCRIPT_ERROR_H
 
+#include <string>
+
 enum class ScriptError {
     OK = 0,
     UNKNOWN,
@@ -85,7 +87,7 @@
 
 #define SCRIPT_ERR_LAST ScriptError::ERROR_COUNT
 
-const char *ScriptErrorString(const ScriptError error);
+std::string ScriptErrorString(const ScriptError error);
 
 namespace {
 
diff --git a/src/script/script_error.cpp b/src/script/script_error.cpp
--- a/src/script/script_error.cpp
+++ b/src/script/script_error.cpp
@@ -5,7 +5,9 @@
 
 #include <script/script_error.h>
 
-const char *ScriptErrorString(const ScriptError serror) {
+#include <string>
+
+std::string ScriptErrorString(const ScriptError serror) {
     switch (serror) {
         case ScriptError::OK:
             return "No error";
diff --git a/src/script/standard.h b/src/script/standard.h
--- a/src/script/standard.h
+++ b/src/script/standard.h
@@ -13,6 +13,8 @@
 
 #include <boost/variant.hpp>
 
+#include <string>
+
 static const bool DEFAULT_ACCEPT_DATACARRIER = true;
 
 class CKeyID;
@@ -90,7 +92,7 @@
 bool IsValidDestination(const CTxDestination &dest);
 
 /** Get the name of a txnouttype as a C string, or nullptr if unknown. */
-const char *GetTxnOutputType(txnouttype t);
+std::string GetTxnOutputType(txnouttype t);
 
 /**
  * Parse a scriptPubKey and identify script type for standard scripts. If
diff --git a/src/script/standard.cpp b/src/script/standard.cpp
--- a/src/script/standard.cpp
+++ b/src/script/standard.cpp
@@ -8,6 +8,8 @@
 #include <crypto/sha256.h>
 #include <script/script.h>
 
+#include <string>
+
 typedef std::vector<uint8_t> valtype;
 
 bool fAcceptDatacarrier = DEFAULT_ACCEPT_DATACARRIER;
@@ -20,7 +22,7 @@
 
 PKHash::PKHash(const CPubKey &pubkey) : uint160(pubkey.GetID()) {}
 
-const char *GetTxnOutputType(txnouttype t) {
+std::string GetTxnOutputType(txnouttype t) {
     switch (t) {
         case TX_NONSTANDARD:
             return "nonstandard";
@@ -35,7 +37,7 @@
         case TX_NULL_DATA:
             return "nulldata";
     }
-    return nullptr;
+    assert(false);
 }
 
 static bool MatchPayToPubkey(const CScript &script, valtype &pubkey) {
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -95,7 +95,7 @@
     {ScriptError::INVALID_BIT_RANGE, "BIT_RANGE"},
 };
 
-static const char *FormatScriptError(ScriptError err) {
+static std::string FormatScriptError(ScriptError err) {
     for (size_t i = 0; i < ARRAYLEN(script_errors); ++i) {
         if (script_errors[i].err == err) {
             return script_errors[i].name;
@@ -138,10 +138,9 @@
                                          &tx, 0, txCredit.vout[0].nValue),
                                      &err) == expect,
                         message);
-    BOOST_CHECK_MESSAGE(err == scriptError,
-                        std::string(FormatScriptError(err)) + " where " +
-                            std::string(FormatScriptError(scriptError)) +
-                            " expected: " + message);
+    BOOST_CHECK_MESSAGE(err == scriptError, FormatScriptError(err) + " where " +
+                                                FormatScriptError(scriptError) +
+                                                " expected: " + message);
 
     // Verify that removing flags from a passing test or adding flags to a
     // failing test does not change the result, except for some special flags.