Merge pull request #2160 from monarchdodra/emplaceRef

Make emplaceRef parameter optional

std/conv.d

@@ -3819,15 +3819,28 @@ emplace, but takes its argument by ref (as opposed to "by pointer").
 This makes it easier to use, easier to be safe, and faster in a non-inline
 build.
 
-Furthermore, emplaceRef takes a type paremeter, which specifies the type we
-want to build. This helps to build qualified objects on mutable buffer,
-without breaking the type system with unsafe casts.
+Furthermore, emplaceRef optionally takes a type paremeter, which specifies
+the type we want to build. This helps to build qualified objects on mutable
+buffer, without breaking the type system with unsafe casts.
 +/
-package template emplaceRef(T)
+package ref UT emplaceRef(UT, Args...)(ref UT chunk, auto ref Args args)
+if (is(UT == Unqual!UT))
+{
+    return emplaceImpl!UT(chunk, args);
+}
+// ditto
+package ref UT emplaceRef(T, UT, Args...)(ref UT chunk, auto ref Args args)
+if (is(UT == Unqual!T) && !is(T == UT))
+{
+    return emplaceImpl!T(chunk, args);
+}
+
+
+private template emplaceImpl(T)
 {
     alias UT = Unqual!T;
 
-    ref UT emplaceRef()(ref UT chunk)
+    ref UT emplaceImpl()(ref UT chunk)
     {
         static assert (is(typeof({static T i;})),
             format("Cannot emplace a %1$s because %1$s.this() is annotated with @disable.", T.stringof));
@@ -3836,7 +3849,7 @@ package template emplaceRef(T)
     }
 
     static if (!is(T == struct))
-    ref UT emplaceRef(Arg)(ref UT chunk, auto ref Arg arg)
+    ref UT emplaceImpl(Arg)(ref UT chunk, auto ref Arg arg)
     {
         static assert(is(typeof({T t = arg;})),
             format("%s cannot be emplaced from a %s.", T.stringof, Arg.stringof));
@@ -3860,7 +3873,7 @@ package template emplaceRef(T)
                         typeid(T).postblit(cast(void*)&chunk);
                 }
                 else
-                    .emplaceRef!T(chunk, cast(T)arg);
+                    .emplaceImpl!T(chunk, cast(T)arg);
             }
             else static if (is(Arg : E[]))
             {
@@ -3875,7 +3888,7 @@ package template emplaceRef(T)
                         typeid(T).postblit(cast(void*)&chunk);
                 }
                 else
-                    .emplaceRef!T(chunk, cast(E[])arg);
+                    .emplaceImpl!T(chunk, cast(E[])arg);
             }
             else static if (is(Arg : E))
             {
@@ -3893,9 +3906,9 @@ package template emplaceRef(T)
                 }
                 else
                     //Alias this. Coerce.
-                    .emplaceRef!T(chunk, cast(E)arg);
+                    .emplaceImpl!T(chunk, cast(E)arg);
             }
-            else static if (is(typeof(.emplaceRef!E(chunk[0], arg))))
+            else static if (is(typeof(.emplaceImpl!E(chunk[0], arg))))
             {
                 //Final case for everything else:
                 //Types that don't match (int to uint[2])
@@ -3904,7 +3917,7 @@ package template emplaceRef(T)
                     chunk[] = arg;
                 else
                     foreach(i; 0 .. N)
-                        .emplaceRef!E(chunk[i], arg);
+                        .emplaceImpl!E(chunk[i], arg);
             }
             else
                 static assert(0, format("Sorry, this implementation doesn't know how to emplace a %s with a %s", T.stringof, Arg.stringof));
@@ -3919,7 +3932,7 @@ package template emplaceRef(T)
     }
     // ditto
     static if (is(T == struct))
-    ref UT emplaceRef(Args...)(ref UT chunk, auto ref Args args)
+    ref UT emplaceImpl(Args...)(ref UT chunk, auto ref Args args)
     {
         static if (Args.length == 1 && is(Args[0] : T) &&
             is (typeof({T t = args[0];})) //Check for legal postblit
@@ -3939,7 +3952,7 @@ package template emplaceRef(T)
             }
             else
                 //Alias this. Coerce to type T.
-                .emplaceRef!T(chunk, cast(T)args[0]);
+                .emplaceImpl!T(chunk, cast(T)args[0]);
         }
         else static if (is(typeof(chunk.__ctor(args))))
         {
@@ -3963,9 +3976,9 @@ package template emplaceRef(T)
                 alias Field = typeof(field);
                 alias UField = Unqual!Field;
                 static if (is(Field == UField))
-                    .emplaceRef!Field(field, args[i]);
+                    .emplaceImpl!Field(field, args[i]);
                 else
-                    .emplaceRef!Field(*cast(Unqual!Field*)&field, args[i]);
+                    .emplaceImpl!Field(*cast(Unqual!Field*)&field, args[i]);
             }
         }
         else
@@ -3999,7 +4012,7 @@ ref T emplaceOpCaller(T, Args...)(ref T chunk, auto ref Args args)
 {
     static assert (is(typeof({T t = T.opCall(args);})),
         format("%s.opCall does not return adequate data for construction.", T.stringof));
-    return emplaceRef!T(chunk, chunk.opCall(args));
+    return emplaceImpl!T(chunk, chunk.opCall(args));
 }
 
 
@@ -4014,7 +4027,7 @@ as $(D chunk)).
  */
 T* emplace(T)(T* chunk) @safe pure nothrow
 {
-    emplaceRef!T(*chunk);
+    emplaceImpl!T(*chunk);
     return chunk;
 }
 
@@ -4032,14 +4045,14 @@ as $(D chunk)).
 T* emplace(T, Args...)(T* chunk, auto ref Args args)
 if (!is(T == struct) && Args.length == 1)
 {
-    emplaceRef!T(*chunk, args);
+    emplaceImpl!T(*chunk, args);
     return chunk;
 }
 /// ditto
 T* emplace(T, Args...)(T* chunk, auto ref Args args)
 if (is(T == struct))
 {
-    emplaceRef!T(*chunk, args);
+    emplaceImpl!T(*chunk, args);
     return chunk;
 }
 
@@ -4854,6 +4867,15 @@ unittest //Constness
     emplaceRef!(IS[2])(ss, iss[]);
 }
 
+unittest
+{
+    int i;
+    emplaceRef(i);
+    emplaceRef!int(i);
+    emplaceRef(i, 5);
+    emplaceRef!int(i, 5);
+}
+
 private void testEmplaceChunk(void[] chunk, size_t typeSize, size_t typeAlignment, string typeName)
 {
     enforceEx!ConvException(chunk.length >= typeSize,