Merge pull request #4366 from malytomas/master

fix compilation with clangcl on windows

include/assimp/Exceptional.h

@@ -98,10 +98,6 @@ public:
             DeadlyErrorBase(Assimp::Formatter::format(), std::forward<T>(args)...) {
         // empty
     }
-
-#if defined(_MSC_VER) && defined(__clang__)
-    DeadlyImportError(DeadlyImportError& other) = delete;
-#endif
 };
 
 // ---------------------------------------------------------------------------
@@ -114,10 +110,6 @@ public:
     template<typename... T>
     explicit DeadlyExportError(T&&... args) :
             DeadlyErrorBase(Assimp::Formatter::format(), std::forward<T>(args)...) {}
-
-#if defined(_MSC_VER) && defined(__clang__)
-    DeadlyExportError(DeadlyExportError& other) = delete;
-#endif
 };
 
 #ifdef _MSC_VER

include/assimp/TinyFormatter.h

@@ -119,29 +119,41 @@ public:
      * work for const references, so many function prototypes will
      * include const basic_formatter<T>& s but might still want to
      * modify the formatted string without the need for a full copy.*/
-    template <typename TToken>
-    const basic_formatter& operator << (const TToken& s) const {
+    template <typename TToken, typename std::enable_if<!std::is_base_of<std::exception, TToken>::value>::type * = nullptr>
+    const basic_formatter &operator<<(const TToken &s) const {
         underlying << s;
         return *this;
     }
 
-    template <typename TToken>
-    basic_formatter& operator << (const TToken& s) {
+    template <typename TToken, typename std::enable_if<std::is_base_of<std::exception, TToken>::value>::type * = nullptr>
+    const basic_formatter &operator<<(const TToken &s) const {
+        underlying << s.what();
+        return *this;
+    }
+
+    template <typename TToken, typename std::enable_if<!std::is_base_of<std::exception, TToken>::value>::type * = nullptr>
+    basic_formatter &operator<<(const TToken &s) {
         underlying << s;
         return *this;
     }
 
+    template <typename TToken, typename std::enable_if<std::is_base_of<std::exception, TToken>::value>::type * = nullptr>
+    basic_formatter &operator<<(const TToken &s) {
+        underlying << s.what();
+        return *this;
+    }
+
 
     // comma operator overloaded as well, choose your preferred way.
     template <typename TToken>
     const basic_formatter& operator, (const TToken& s) const {
-        underlying << s;
+        *this << s;
         return *this;
     }
 
     template <typename TToken>
     basic_formatter& operator, (const TToken& s) {
-        underlying << s;
+        *this << s;
         return *this;
     }
 
@@ -149,7 +161,7 @@ public:
     // See https://sourceforge.net/projects/assimp/forums/forum/817654/topic/4372824
     template <typename TToken>
     basic_formatter& operator, (TToken& s) {
-        underlying << s;
+        *this << s;
         return *this;
     }