diff --git a/std/parallelism.d b/std/parallelism.d
index 683a3cf8757..fc994f82c69 100644
--- a/std/parallelism.d
+++ b/std/parallelism.d
@@ -82,11 +82,9 @@ import core.thread;
 
 import std.algorithm;
 import std.conv;
-import std.exception;
 import std.functional;
-import std.math;
 import std.meta;
-import std.range;
+import std.range.primitives;
 import std.traits;
 import std.typecons;
 
@@ -537,6 +535,7 @@ struct Task(alias fun, Args...)
 
     private void enforcePool()
     {
+        import std.exception : enforce;
         enforce(this.pool !is null, "Job not submitted yet.");
     }
 
@@ -1529,6 +1528,7 @@ public:
     */
     ParallelForeach!R parallel(R)(R range, size_t workUnitSize)
     {
+        import std.exception : enforce;
         enforce(workUnitSize > 0, "workUnitSize must be > 0.");
         alias RetType = ParallelForeach!R;
         return RetType(this, range, workUnitSize);
@@ -1653,6 +1653,7 @@ public:
                 is(MapType!(Args[0], functions) : ElementType!(Args[$ - 1]))
                 )
             {
+                import std.exception : enforce;
                 alias buf = args[$ - 1];
                 alias args2 = args[0..$ - 1];
                 alias Args2 = Args[0..$ - 1];
@@ -1666,6 +1667,8 @@ public:
             }
             else
             {
+                import std.array : uninitializedArray;
+
                 auto buf = uninitializedArray!(MapType!(Args[0], functions)[])(len);
                 alias args2 = args;
                 alias Args2 = Args;
@@ -1826,6 +1829,8 @@ public:
         map(S)(S source, size_t bufSize = 100, size_t workUnitSize = size_t.max)
         if (isInputRange!S)
         {
+            import std.exception : enforce;
+
             enforce(workUnitSize == size_t.max || workUnitSize <= bufSize,
                     "Work unit size must be smaller than buffer size.");
             alias fun = adjoin!(staticMap!(unaryFun, functions));
@@ -1978,6 +1983,7 @@ public:
                 {
                     static if (isRandomAccessRange!S)
                     {
+                        import std.range : take;
                         auto toMap = take(source, buf.length);
                         scope(success) popSource();
                     }
@@ -2476,6 +2482,8 @@ public:
             }
             else
             {
+                import std.exception : enforce;
+
                 static assert(args2.length == 1);
                 alias range = args2[0];
 
@@ -3183,6 +3191,7 @@ public:
     @trusted void put(alias fun, Args...)(Task!(fun, Args)* task)
     if (isSafeReturn!(typeof(*task)))
     {
+        import std.exception : enforce;
         enforce(task !is null, "Cannot put a null Task on a TaskPool queue.");
         put(*task);
     }
@@ -3611,6 +3620,7 @@ enum string parallelApplyMixinInputRange = q{
             size_t makeTemp()
             {
                 import std.algorithm.internal : addressOf;
+                import std.array : uninitializedArray;
 
                 if (temp is null)
                 {
@@ -3642,6 +3652,8 @@ enum string parallelApplyMixinInputRange = q{
             // Returns:  The previous value of nPopped.
             static if (!bufferTrick) size_t makeTemp()
             {
+                import std.array : uninitializedArray;
+
                 if (temp is null)
                 {
                     temp = uninitializedArray!Temp(workUnitSize);
@@ -3897,6 +3909,10 @@ version(unittest)
 // These are the tests that should be run every time Phobos is compiled.
 unittest
 {
+    import std.exception : assertThrown;
+    import std.math : log, approxEqual, sqrt;
+    import std.range : iota;
+
     poolInstance = new TaskPool(2);
     scope(exit) poolInstance.stop();
 
@@ -4151,6 +4167,7 @@ unittest
            ));
 
     {
+        import std.array : join, split;
         import std.file : deleteme;
 
         string temp_file = deleteme ~ "-tempDelMe.txt";