diff --git a/src/dmd/dmodule.d b/src/dmd/dmodule.d
index 9a301265ef61..a782a3e041cc 100644
--- a/src/dmd/dmodule.d
+++ b/src/dmd/dmodule.d
@@ -51,113 +51,6 @@ import dmd.target;
 import dmd.utils;
 import dmd.visitor;
 
-enum package_d  = "package." ~ mars_ext;
-enum package_di = "package." ~ hdr_ext;
-
-/********************************************
- * Look for the source file if it's different from filename.
- * Look for .di, .d, directory, and along global.path.
- * Does not open the file.
- * Params:
- *      filename = as supplied by the user
- *      path = path to look for filename
- * Returns:
- *      the found file name or
- *      `null` if it is not different from filename.
- */
-const(char)[] lookForSourceFile(const char[] filename, const char*[] path) nothrow
-{
-    //printf("lookForSourceFile(`%.*s`)\n", cast(int)filename.length, filename.ptr);
-    /* Search along path[] for .di file, then .d file, then .i file, then .c file.
-     */
-    const sdi = FileName.forceExt(filename, hdr_ext);
-    if (FileName.exists(sdi) == 1)
-        return sdi;
-    scope(exit) FileName.free(sdi.ptr);
-
-    const sd = FileName.forceExt(filename, mars_ext);
-    if (FileName.exists(sd) == 1)
-        return sd;
-    scope(exit) FileName.free(sd.ptr);
-
-    const si = FileName.forceExt(filename, i_ext);
-    if (FileName.exists(si) == 1)
-        return si;
-    scope(exit) FileName.free(si.ptr);
-
-    const sc = FileName.forceExt(filename, c_ext);
-    if (FileName.exists(sc) == 1)
-        return sc;
-    scope(exit) FileName.free(sc.ptr);
-
-    if (FileName.exists(filename) == 2)
-    {
-        /* The filename exists and it's a directory.
-         * Therefore, the result should be: filename/package.d
-         * iff filename/package.d is a file
-         */
-        const ni = FileName.combine(filename, package_di);
-        if (FileName.exists(ni) == 1)
-            return ni;
-        FileName.free(ni.ptr);
-
-        const n = FileName.combine(filename, package_d);
-        if (FileName.exists(n) == 1)
-            return n;
-        FileName.free(n.ptr);
-    }
-    if (FileName.absolute(filename))
-        return null;
-    if (!path.length)
-        return null;
-    foreach (entry; path)
-    {
-        const p = entry.toDString();
-
-        const(char)[] n = FileName.combine(p, sdi);
-        if (FileName.exists(n) == 1) {
-            return n;
-        }
-        FileName.free(n.ptr);
-
-        n = FileName.combine(p, sd);
-        if (FileName.exists(n) == 1) {
-            return n;
-        }
-        FileName.free(n.ptr);
-
-        n = FileName.combine(p, si);
-        if (FileName.exists(n) == 1) {
-            return n;
-        }
-        FileName.free(n.ptr);
-
-        n = FileName.combine(p, sc);
-        if (FileName.exists(n) == 1) {
-            return n;
-        }
-        FileName.free(n.ptr);
-
-        const b = FileName.removeExt(filename);
-        n = FileName.combine(p, b);
-        FileName.free(b.ptr);
-        if (FileName.exists(n) == 2)
-        {
-            const n2i = FileName.combine(n, package_di);
-            if (FileName.exists(n2i) == 1)
-                return n2i;
-            FileName.free(n2i.ptr);
-            const n2 = FileName.combine(n, package_d);
-            if (FileName.exists(n2) == 1) {
-                return n2;
-            }
-            FileName.free(n2.ptr);
-        }
-        FileName.free(n.ptr);
-    }
-    return null;
-}
-
 // function used to call semantic3 on a module's dependencies
 void semantic3OnDependencies(Module m)
 {
@@ -415,7 +308,7 @@ extern (C++) class Package : ScopeDsymbol
             packages ~= s.ident;
         reverse(packages);
 
-        if (lookForSourceFile(getFilename(packages, ident), global.path ? (*global.path)[] : null))
+        if (FileManager.lookForSourceFile(getFilename(packages, ident), global.path ? (*global.path)[] : null))
             Module.load(Loc.initial, packages, this.ident);
         else
             isPkgMod = PKG.package_;
@@ -613,7 +506,7 @@ extern (C++) final class Module : Package
         //  foo\bar\baz
         const(char)[] filename = getFilename(packages, ident);
         // Look for the source file
-        if (const result = lookForSourceFile(filename, global.path ? (*global.path)[] : null))
+        if (const result = FileManager.lookForSourceFile(filename, global.path ? (*global.path)[] : null))
             filename = result; // leaks
 
         auto m = new Module(loc, filename, ident, 0, 0);
diff --git a/src/dmd/file_manager.d b/src/dmd/file_manager.d
index 3fd0e8c21ccc..37d69b2a67af 100644
--- a/src/dmd/file_manager.d
+++ b/src/dmd/file_manager.d
@@ -14,11 +14,12 @@ import dmd.root.stringtable : StringTable;
 import dmd.root.file : File, FileBuffer;
 import dmd.root.filename : FileName;
 import dmd.root.string : toDString;
-import dmd.arraytypes;
-import dmd.dmodule : lookForSourceFile;
-import dmd.globals : global;
+import dmd.globals;
 import dmd.identifier;
 
+enum package_d  = "package." ~ mars_ext;
+enum package_di = "package." ~ hdr_ext;
+
 extern(C++) struct FileManager
 {
     private StringTable!(FileBuffer*) files;
@@ -51,6 +52,110 @@ nothrow:
 
     }
 
+    /********************************************
+    * Look for the source file if it's different from filename.
+    * Look for .di, .d, directory, and along global.path.
+    * Does not open the file.
+    * Params:
+    *      filename = as supplied by the user
+    *      path = path to look for filename
+    * Returns:
+    *      the found file name or
+    *      `null` if it is not different from filename.
+    */
+    extern(D) static const(char)[] lookForSourceFile(const char[] filename, const char*[] path) nothrow
+    {
+        //printf("lookForSourceFile(`%.*s`)\n", cast(int)filename.length, filename.ptr);
+        /* Search along path[] for .di file, then .d file, then .i file, then .c file.
+        */
+        const sdi = FileName.forceExt(filename, hdr_ext);
+        if (FileName.exists(sdi) == 1)
+            return sdi;
+        scope(exit) FileName.free(sdi.ptr);
+
+        const sd = FileName.forceExt(filename, mars_ext);
+        if (FileName.exists(sd) == 1)
+            return sd;
+        scope(exit) FileName.free(sd.ptr);
+
+        const si = FileName.forceExt(filename, i_ext);
+        if (FileName.exists(si) == 1)
+            return si;
+        scope(exit) FileName.free(si.ptr);
+
+        const sc = FileName.forceExt(filename, c_ext);
+        if (FileName.exists(sc) == 1)
+            return sc;
+        scope(exit) FileName.free(sc.ptr);
+
+        if (FileName.exists(filename) == 2)
+        {
+            /* The filename exists and it's a directory.
+            * Therefore, the result should be: filename/package.d
+            * iff filename/package.d is a file
+            */
+            const ni = FileName.combine(filename, package_di);
+            if (FileName.exists(ni) == 1)
+                return ni;
+            FileName.free(ni.ptr);
+
+            const n = FileName.combine(filename, package_d);
+            if (FileName.exists(n) == 1)
+                return n;
+            FileName.free(n.ptr);
+        }
+        if (FileName.absolute(filename))
+            return null;
+        if (!path.length)
+            return null;
+        foreach (entry; path)
+        {
+            const p = entry.toDString();
+
+            const(char)[] n = FileName.combine(p, sdi);
+            if (FileName.exists(n) == 1) {
+                return n;
+            }
+            FileName.free(n.ptr);
+
+            n = FileName.combine(p, sd);
+            if (FileName.exists(n) == 1) {
+                return n;
+            }
+            FileName.free(n.ptr);
+
+            n = FileName.combine(p, si);
+            if (FileName.exists(n) == 1) {
+                return n;
+            }
+            FileName.free(n.ptr);
+
+            n = FileName.combine(p, sc);
+            if (FileName.exists(n) == 1) {
+                return n;
+            }
+            FileName.free(n.ptr);
+
+            const b = FileName.removeExt(filename);
+            n = FileName.combine(p, b);
+            FileName.free(b.ptr);
+            if (FileName.exists(n) == 2)
+            {
+                const n2i = FileName.combine(n, package_di);
+                if (FileName.exists(n2i) == 1)
+                    return n2i;
+                FileName.free(n2i.ptr);
+                const n2 = FileName.combine(n, package_d);
+                if (FileName.exists(n2) == 1) {
+                    return n2;
+                }
+                FileName.free(n2.ptr);
+            }
+            FileName.free(n.ptr);
+        }
+        return null;
+    }
+
     /**
      * Looks up the given filename from the internal file buffer table.
      * If the file does not already exist within the table, it will be read from the filesystem.