QStringConverter: make explicit what should never have been implicit

As a drive-by, remove the GCC 7 constexpr work-around.

[ChangeLog][Potentially Source-Incompatible Changes]
All QStringEncoder/Decoder constructors are now explicit.

Change-Id: I0972e2736115993d44a48e73dbf4b08a1c94bef2
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 11 insertions, 20 deletions

diff --git a/src/corelib/text/qstringconverter.h b/src/corelib/text/qstringconverter.h
index 4d2138f143..dcc2b4a433 100644
--- a/src/corelib/text/qstringconverter.h
+++ b/src/corelib/text/qstringconverter.h
@@ -55,27 +55,20 @@
 
 QT_BEGIN_NAMESPACE
 
-// work around a compiler bug in GCC 7
-#if (defined(Q_CC_GNU) && __GNUC__ == 7) || defined(Q_QDOC)
-#define QSTRINGCONVERTER_CONSTEXPR
-#else
-#define QSTRINGCONVERTER_CONSTEXPR constexpr
-#endif
-
 class QStringEncoder : public QStringConverter
 {
 protected:
-    QSTRINGCONVERTER_CONSTEXPR QStringEncoder(const Interface *i)
+    constexpr explicit QStringEncoder(const Interface *i)
         : QStringConverter(i)
     {}
 public:
-    QSTRINGCONVERTER_CONSTEXPR QStringEncoder()
+    constexpr QStringEncoder()
         : QStringConverter()
     {}
-    QSTRINGCONVERTER_CONSTEXPR QStringEncoder(Encoding encoding, Flags flags = Flag::Default)
+    constexpr explicit QStringEncoder(Encoding encoding, Flags flags = Flag::Default)
         : QStringConverter(encoding, flags)
     {}
-    QStringEncoder(const char *name, Flags flags = Flag::Default)
+    explicit QStringEncoder(const char *name, Flags flags = Flag::Default)
         : QStringConverter(name, flags)
     {}
 
@@ -123,17 +116,17 @@ private:
 class QStringDecoder : public QStringConverter
 {
 protected:
-    QSTRINGCONVERTER_CONSTEXPR QStringDecoder(const Interface *i)
+    constexpr explicit QStringDecoder(const Interface *i)
         : QStringConverter(i)
     {}
 public:
-    QSTRINGCONVERTER_CONSTEXPR QStringDecoder(Encoding encoding, Flags flags = Flag::Default)
+    constexpr explicit QStringDecoder(Encoding encoding, Flags flags = Flag::Default)
         : QStringConverter(encoding, flags)
     {}
-    QSTRINGCONVERTER_CONSTEXPR QStringDecoder()
+    constexpr QStringDecoder()
         : QStringConverter()
     {}
-    QStringDecoder(const char *name, Flags f = Flag::Default)
+    explicit QStringDecoder(const char *name, Flags f = Flag::Default)
         : QStringConverter(name, f)
     {}
 
@@ -231,6 +224,4 @@ QByteArray &operator+=(QByteArray &a, const QStringEncoder::DecodedData<T> &b)
 
 QT_END_NAMESPACE
 
-#undef QSTRINGCONVERTER_CONSTEXPR
-
 #endif
diff --git a/src/corelib/text/qstringconverter_base.h b/src/corelib/text/qstringconverter_base.h
index dd84cf8744..23a011d297 100644
--- a/src/corelib/text/qstringconverter_base.h
+++ b/src/corelib/text/qstringconverter_base.h
@@ -158,13 +158,13 @@ protected:
     constexpr QStringConverter()
         : iface(nullptr)
     {}
-    constexpr QStringConverter(Encoding encoding, Flags f)
+    constexpr explicit QStringConverter(Encoding encoding, Flags f)
         : iface(&encodingInterfaces[int(encoding)]), state(f)
     {}
-    constexpr QStringConverter(const Interface *i)
+    constexpr explicit QStringConverter(const Interface *i)
         : iface(i)
     {}
-    Q_CORE_EXPORT QStringConverter(const char *name, Flags f);
+    Q_CORE_EXPORT explicit QStringConverter(const char *name, Flags f);
 
 
 public: