diff --git a/std/algorithm.d b/std/algorithm.d
index fe368ec53..440c1326e 100644
--- a/std/algorithm.d
+++ b/std/algorithm.d
@@ -352,10 +352,7 @@ module std.algorithm;
 
 import std.functional : unaryFun, binaryFun;
 import std.range;
-import std.traits : isIntegral, mostNegative, isSomeString, isMutable, Select,
-    isArray, hasElaborateAssign, isStaticArray, isNarrowString, isIterable,
-    Unqual, hasElaborateDestructor, unsigned, ForeachType, isDynamicArray,
-    hasElaborateCopyConstructor, CommonType;
+import std.traits;
 import std.typetuple : TypeTuple, staticMap, allSatisfy;
 
 version(unittest)
@@ -657,6 +654,7 @@ unittest
 
 unittest
 {
+    import std.range;
     // Issue #10130 - map of iota with const step.
     const step = 2;
     static assert(__traits(compiles, map!(i => i)(iota(0, 10, step))));
diff --git a/std/range.d b/std/range.d
index 7de17ed99..8cc8b8061 100644
--- a/std/range.d
+++ b/std/range.d
@@ -2091,6 +2091,7 @@ assert(stride(stride(a, 2), 3) == stride(a, 6));
 auto stride(Range)(Range r, size_t n)
 if (isInputRange!(Unqual!Range))
 {
+    import std.exception;
     enforce(n > 0, "Stride cannot have step zero.");
 
     static if (is(typeof(stride(r.source, n)) == Range))
@@ -3019,6 +3020,7 @@ unittest
     import std.conv : text;
     void test(int[] input, int[] witness)
     {
+        import std.exception;
         enforce(equal(radial(input), witness),
                 text(radial(input), " vs. ", witness));
     }
@@ -4219,6 +4221,7 @@ Take!(Repeat!T) repeat(T)(T value, size_t n)
 
 unittest
 {
+    import std.exception;
     enforce(equal(repeat(5, 4), [ 5, 5, 5, 5 ][]));
 }
 
@@ -4627,6 +4630,7 @@ struct Zip(Ranges...)
             case StoppingPolicy.requireSameLength:
                 foreach (i, Unused; R[1 .. $])
                 {
+                    import std.exception;
                     enforce(ranges[0].empty ==
                             ranges[i + 1].empty,
                             "Inequal-length ranges passed to Zip");
@@ -4806,6 +4810,7 @@ struct Zip(Ranges...)
         case StoppingPolicy.requireSameLength:
             foreach (i, Unused; R)
             {
+                import std.exception;
                 enforce(!ranges[i].empty, "Invalid Zip object");
                 ranges[i].popFront();
             }
@@ -4837,6 +4842,7 @@ struct Zip(Ranges...)
             case StoppingPolicy.requireSameLength:
                 foreach (i, Unused; R)
                 {
+                    import std.exception;
                     enforce(!ranges[i].empty, "Invalid Zip object");
                     ranges[i].popBack();
                 }
@@ -5158,6 +5164,7 @@ private string lockstepMixin(Ranges...)(bool withIndex)
 
             if (_stoppingPolicy == StoppingPolicy.requireSameLength)
             {
+                import std.exception;
                 foreach(range; ranges)
                     enforce(range.empty);
             }
@@ -5208,6 +5215,7 @@ struct Lockstep(Ranges...)
     this(R ranges, StoppingPolicy sp = StoppingPolicy.shortest)
     {
         _ranges = ranges;
+        import std.exception;
         enforce(sp != StoppingPolicy.longest,
                 "Can't use StoppingPolicy.Longest on Lockstep.");
         _stoppingPolicy = sp;
@@ -5605,6 +5613,7 @@ if ((isIntegral!(CommonType!(B, E)) || isPointer!(CommonType!(B, E)))
             if ((current < pastLast && step >= 0) ||
                     (current > pastLast && step <= 0))
             {
+                import std.exception;
                 enforce(step != 0);
                 this.step = step;
                 this.current = current;
@@ -5761,6 +5770,7 @@ if (isFloatingPoint!(CommonType!(B, E, S)))
         {
             this.start = start;
             this.step = step;
+            import std.exception;
             enforce(step != 0);
             immutable fcount = (end - start) / step;
             enforce(fcount >= 0, "iota: incorrect startup parameters");
@@ -6078,6 +6088,7 @@ struct FrontTransversal(Ror,
             immutable commonLength = _input.front.length;
             foreach (e; _input)
             {
+                import std.exception;
                 enforce(e.length == commonLength);
             }
         }
@@ -6352,6 +6363,7 @@ struct Transversal(Ror,
             immutable commonLength = _input.front.length;
             foreach (e; _input)
             {
+                import std.exception;
                 enforce(e.length == commonLength);
             }
         }
diff --git a/std/stdio.d b/std/stdio.d
index 03c809475..393b54990 100644
--- a/std/stdio.d
+++ b/std/stdio.d
@@ -18,16 +18,10 @@ module std.stdio;
 
 public import core.stdc.stdio, std.string : KeepTerminator;
 static import std.c.stdio;
-import std.algorithm : equal, swap, endsWith;
 import std.stdiobase;
 import core.stdc.errno, core.stdc.stddef, core.stdc.stdlib, core.memory,
     core.stdc.string, core.stdc.wchar_, core.exception;
-import std.conv : text, to, toTextRange;
-import std.exception : assumeUnique, collectException, enforce, errnoEnforce;
-import std.format : formattedRead;
-import std.array : empty;
 import std.range;
-import std.string : format, toStringz, chomp;
 import std.traits : Unqual, isSomeChar, isAggregateType, isSomeString,
     isIntegral, isBoolean, ParameterTypeTuple;
 
@@ -225,6 +219,7 @@ public:
     /// Ditto
     void popFront()
     {
+        import std.exception;
         enforce(file.isOpen);
         file.readln(line);
         if (!line.length)
@@ -233,8 +228,11 @@ public:
         }
         else
         {
+            import std.conv, std.format, std.string : chomp;
             line = chomp(line);
             formattedRead(line, format, &current);
+            import std.conv;
+            import std.array;
             enforce(line.empty, text("Leftover characters in record: `",
                             line, "'"));
         }
@@ -297,6 +295,7 @@ Hello, Jimmy!
  */
 struct File
 {
+    import std.traits;
     private struct Impl
     {
         FILE * handle = null; // Is null iff this Impl is closed by another File
@@ -309,6 +308,7 @@ struct File
     package this(FILE* handle, string name, uint refs = 1, bool isPopened = false)
     {
         assert(!_p);
+        import std.exception;
         _p = cast(Impl*) enforce(malloc(Impl.sizeof), "Out of memory");
         _p.handle = handle;
         _p.refs = refs;
@@ -332,6 +332,7 @@ Throws: $(D ErrnoException) if the file could not be opened.
  */
     this(string name, in char[] stdioOpenmode = "rb")
     {
+        import std.conv, std.exception;
         this(errnoEnforce(.fopen(name, stdioOpenmode),
                         text("Cannot open file `", name, "' in mode `",
                                 stdioOpenmode, "'")),
@@ -357,6 +358,7 @@ file.
  */
     void opAssign(File rhs)
     {
+        import std.algorithm;
         swap(this, rhs);
     }
 
@@ -384,6 +386,7 @@ Throws: $(D ErrnoException) in case of error.
     version(Posix) void popen(string command, in char[] stdioOpenmode = "r")
     {
         detach();
+        import std.exception;
         this = File(errnoEnforce(.popen(command, stdioOpenmode),
                         "Cannot run command `"~command~"'"),
                 command, 1, true);
@@ -403,6 +406,7 @@ Throws: $(D Exception) if the file is not opened.
  */
     @property bool eof() const pure
     {
+        import std.exception;
         enforce(_p && _p.handle, "Calling eof() against an unopened file.");
         return .feof(cast(FILE*) _p.handle) != 0;
     }
@@ -470,6 +474,7 @@ Throws: $(D ErrnoException) on error.
  */
     void close()
     {
+        import std.exception;
         if (!_p) return; // succeed vacuously
         scope(exit)
         {
@@ -488,6 +493,7 @@ Throws: $(D ErrnoException) on error.
                 auto res = .pclose(_p.handle);
                 errnoEnforce(res != -1,
                         "Could not close pipe `"~_name~"'");
+                import std.string;
                 errnoEnforce(res == 0, format("Command returned %d", res));
                 return;
             }
@@ -516,6 +522,7 @@ Throws: $(D Exception) if the file is not opened or if the call to $D(fflush) fa
  */
     void flush()
     {
+        import std.exception;
         errnoEnforce
         (.fflush(enforce(_p.handle, "Calling fflush() on an unopened file"))
                 == 0);
@@ -537,6 +544,7 @@ $(D rawRead) always reads in binary mode on Windows.
  */
     T[] rawRead(T)(T[] buffer)
     {
+        import std.exception;
         enforce(buffer.length, "rawRead must take a non-empty buffer");
         version(Win32)
         {
@@ -602,6 +610,7 @@ Throws: $(D ErrnoException) if the file is not opened or if the call to $D(fread
         auto result =
             .fwrite(buffer.ptr, T.sizeof, buffer.length, _p.handle);
         if (result == result.max) result = 0;
+        import std.conv, std.exception;
         errnoEnforce(result == buffer.length,
                 text("Wrote ", result, " instead of ", buffer.length,
                         " objects of type ", T.stringof, " to file `",
@@ -628,9 +637,11 @@ Throws: $(D Exception) if the file is not opened.
  */
     void seek(long offset, int origin = SEEK_SET)
     {
+        import std.exception;
         enforce(isOpen, "Attempting to seek() in an unopened file");
         version (Windows)
         {
+            import std.conv;
             errnoEnforce(fseek(_p.handle, to!int(offset), origin) == 0,
                     "Could not seek in file `"~_name~"'");
         }
@@ -659,6 +670,7 @@ Throws: $(D Exception) if the file is not opened.
         {
             auto bigOffset = cast(ulong) int.max + 100;
             f.seek(bigOffset);
+            import std.conv;
             assert(f.tell == bigOffset, text(f.tell));
             // Uncomment the tests below only if you want to wait for
             // a long time
@@ -677,6 +689,7 @@ Throws: $(D Exception) if the file is not opened.
  */
     @property ulong tell() const
     {
+        import std.exception;
         enforce(isOpen, "Attempting to tell() in an unopened file");
         version (Windows)
         {
@@ -699,6 +712,7 @@ Throws: $(D Exception) if the file is not opened.
         auto f = File(deleteme);
         auto a = new ubyte[4];
         f.rawRead(a);
+        import std.conv;
         assert(f.tell == 4, text(f.tell));
     }
 
@@ -710,6 +724,7 @@ Throws: $(D Exception) if the file is not opened.
  */
     void rewind()
     {
+        import std.exception;
         enforce(isOpen, "Attempting to rewind() an unopened file");
         .rewind(_p.handle);
     }
@@ -723,6 +738,7 @@ Throws: $(D Exception) if the file is not opened.
  */
     void setvbuf(size_t size, int mode = _IOFBF)
     {
+        import std.exception;
         enforce(isOpen, "Attempting to call setvbuf() on an unopened file");
         errnoEnforce(.setvbuf(_p.handle, null, mode, size) == 0,
                 "Could not set buffering for file `"~_name~"'");
@@ -737,6 +753,7 @@ Throws: $(D Exception) if the file is not opened.
 */
     void setvbuf(void[] buf, int mode = _IOFBF)
     {
+        import std.exception;
         enforce(isOpen, "Attempting to call setvbuf() on an unopened file");
         errnoEnforce(.setvbuf(_p.handle,
                         cast(char*) buf.ptr, mode, buf.length) == 0,
@@ -765,6 +782,7 @@ Throws: $(D Exception) if the file is not opened.
             }
             else static if (isIntegral!A)
             {
+                import std.conv;
                 toTextRange(arg, w);
             }
             else static if (isBoolean!A)
@@ -860,6 +878,7 @@ void main()
 
     unittest
     {
+        import std.algorithm;
         auto deleteme = testFilename();
         std.file.write(deleteme, "hello\nworld\n");
         scope(exit) std.file.remove(deleteme);
@@ -943,6 +962,7 @@ for every line.
     size_t readln(C)(ref C[] buf, dchar terminator = '\n')
     if (isSomeChar!C && is(Unqual!C == C) && !is(C == enum))
     {
+        import std.exception;
         static if (is(C == char))
         {
             enforce(_p && _p.handle, "Attempt to read from an unopened file.");
@@ -967,6 +987,7 @@ for every line.
     if (isSomeChar!C && is(Unqual!C == C) && !is(C == enum) &&
         isBidirectionalRange!R && is(typeof(terminator.front == dchar.init)))
     {
+        import std.algorithm;
         auto last = terminator.back;
         C[] buf2;
         swap(buf, buf2);
@@ -1013,6 +1034,7 @@ for every line.
     {
         assert(isOpen);
         auto input = LockingTextReader(this);
+        import std.format;
         return formattedRead(input, format, data);
     }
 
@@ -1033,6 +1055,7 @@ for every line.
  Note that the created file has no $(LREF name).*/
     static File tmpfile()
     {
+        import std.exception;
         return File(errnoEnforce(core.stdc.stdio.tmpfile(),
                 "Could not create temporary file with tmpfile()"),
             null);
@@ -1044,6 +1067,7 @@ File) never takes the initiative in closing the file.
 Note that the created file has no $(LREF name)*/
     /*private*/ static File wrapFile(FILE* f)
     {
+        import std.exception;
         return File(enforce(f, "Could not wrap null FILE*"),
             null, /*uint.max / 2*/ 9999);
     }
@@ -1053,6 +1077,7 @@ Returns the $(D FILE*) corresponding to this object.
  */
     FILE* getFP() pure
     {
+        import std.exception;
         enforce(_p && _p.handle,
                 "Attempting to call getFP() on an unopened file");
         return _p.handle;
@@ -1068,6 +1093,7 @@ Returns the file number corresponding to this object.
  */
     /*version(Posix) */int fileno() const
     {
+        import std.exception;
         enforce(isOpen, "Attempting to call fileno() on an unopened file");
         return .fileno(cast(FILE*) _p.handle);
     }
@@ -1169,6 +1195,7 @@ Allows to directly use range operations on lines of a file.
 
         void popFront()
         {
+            import std.algorithm;
             assert(file.isOpen);
             assumeSafeAppend(line);
             file.readln(line, terminator);
@@ -1195,7 +1222,6 @@ Allows to directly use range operations on lines of a file.
         }
     }
 
-    import std.traits;
 /**
 Returns an input range set up to read from the file handle one line
 at a time.
@@ -1270,6 +1296,7 @@ the contents may well have changed).
 
     unittest
     {
+        import std.algorithm;
         //printf("Entering test at line %d\n", __LINE__);
         scope(failure) printf("Failed test at line %d\n", __LINE__);
         auto deleteme = testFilename();
@@ -1307,6 +1334,7 @@ the contents may well have changed).
             {
                 assert(line == witness[i++]);
             }
+            import std.conv;
             assert(i == witness.length, text(i, " != ", witness.length));
         }
         /* Wrap with default args.
@@ -1521,6 +1549,7 @@ $(D Range) that locks the file and allows fast writing to it.
 
         this(ref File f)
         {
+            import std.exception;
             enforce(f._p && f._p.handle);
             fps = f._p.handle;
             orientation = fwide(fps, 0);
@@ -1549,6 +1578,7 @@ $(D Range) that locks the file and allows fast writing to it.
         /// Range primitive implementations.
         void put(A)(A writeme) if (is(ElementType!A : const(dchar)))
         {
+            import std.exception;
             alias ElementEncodingType!A C;
             static assert(!is(C == void));
             if (writeme[0].sizeof == 1 && orientation <= 0)
@@ -1661,6 +1691,7 @@ See $(LREF byChunk) for an example.
 /// Get the size of the file, ulong.max if file is not searchable, but still throws if an actual error occurs.
     @property ulong size()
     {
+        import std.exception;
         ulong pos = void;
         if (collectException(pos = tell)) return ulong.max;
         scope(exit) seek(pos);
@@ -1671,6 +1702,7 @@ See $(LREF byChunk) for an example.
 
 unittest
 {
+    import std.exception;
     auto deleteme = testFilename();
     scope(exit) collectException(std.file.remove(deleteme));
     std.file.write(deleteme, "1 2 3");
@@ -1686,6 +1718,7 @@ struct LockingTextReader
 
     this(File f)
     {
+        import std.exception;
         enforce(f.isOpen);
         _f = f;
         FLOCK(_f._p.handle);
@@ -1704,11 +1737,13 @@ struct LockingTextReader
 
     void opAssign(LockingTextReader r)
     {
+        import std.algorithm;
         swap(this, r);
     }
 
     @property bool empty()
     {
+        import std.exception;
         if (!_f.isOpen || _f.eof) return true;
         if (_crt == _crt.init)
         {
@@ -1737,6 +1772,7 @@ struct LockingTextReader
         version(assert) if (empty) throw new RangeError();
         if (FGETC(cast(_iobuf*) _f._p.handle) == -1)
         {
+            import std.exception;
             enforce(_f.eof);
         }
         _crt = _crt.init;
@@ -1902,6 +1938,7 @@ void writeln(T...)(T args)
 {
     static if (T.length == 0)
     {
+        import std.exception;
         enforce(fputc('\n', .stdout._p.handle) == '\n');
     }
     else static if (T.length == 1 &&
@@ -1911,6 +1948,7 @@ void writeln(T...)(T args)
                     !isAggregateType!(typeof(args[0])))
     {
         // Specialization for strings - a very frequent case
+        import std.exception;
         enforce(fprintf(.stdout._p.handle, "%.*s\n",
                         cast(int) args[0].length, args[0].ptr) >= 0);
     }
@@ -2259,6 +2297,7 @@ unittest
  */
 private FILE* fopen(in char[] name, in char[] mode = "r")
 {
+    import std.string;
     version(Windows)
     {
         import std.utf;
@@ -2290,6 +2329,7 @@ version (Posix)
      */
     FILE* popen(in char[] name, in char[] mode = "r")
     {
+        import std.string;
         return core.sys.posix.stdio.popen(toStringz(name), toStringz(mode));
     }
 }
@@ -2396,6 +2436,7 @@ struct lines
                 Parms[0] i = 0;
             for (;;)
             {
+                import std.conv;
                 if (!f.readln(line, terminator)) break;
                 auto copy = to!(Parms[$ - 1])(line);
                 static if (Parms.length == 2)
@@ -2420,6 +2461,7 @@ struct lines
     // no UTF checking
     int opApplyRaw(D)(scope D dg)
     {
+        import std.exception;
         alias ParameterTypeTuple!(dg) Parms;
         enum duplicate = is(Parms[$ - 1] : immutable(ubyte)[]);
         int result = 1;
@@ -2431,6 +2473,7 @@ struct lines
             Parms[0] line = 0;
         while ((c = FGETC(cast(_iobuf*)f._p.handle)) != -1)
         {
+            import std.conv;
             buffer ~= to!(ubyte)(c);
             if (c == terminator)
             {
@@ -2719,6 +2762,7 @@ Initialize with a message and an error code. */
         {
             auto s = core.stdc.string.strerror(errno);
         }
+        import std.conv;
         auto sysmsg = to!string(s);
         // If e is 0, we don't use the system error message.  (The message
         // is "Success", which is rather pointless for an exception.)
@@ -3163,6 +3207,7 @@ version(linux)
 
     File openNetwork(string host, ushort port)
     {
+        import std.exception;
         auto h = enforce( sock.gethostbyname(std.string.toStringz(host)),
             new StdioException("gethostbyname"));
 
@@ -3187,6 +3232,7 @@ version(linux)
         enforce(sock.connect(s, cast(sock.sockaddr*) &addr, addr.sizeof) != -1,
             new StdioException("Connect failed"));
 
+        import std.conv;
         return File(enforce(fdopen(s, "w+".ptr)),
             host ~ ":" ~ to!string(port));
     }
@@ -3194,7 +3240,7 @@ version(linux)
 
 version(unittest) string testFilename(string file = __FILE__, size_t line = __LINE__)
 {
-    import std.path;
+    import std.conv, std.path;
 
     // Non-ASCII characters can't be used because of snn.lib @@@BUG8643@@@
     version(DIGITAL_MARS_STDIO)