diff --git a/Changes b/Changes
index 418720645..b9f225d21 100644
--- a/Changes
+++ b/Changes
@@ -21,6 +21,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Fix mis-optimizing public DPI functions, bug963. [Wei Song]
 
+****  Fix internal error on interface array, bug978. [Johan Bjork]
+
 
 * Verilator 3.876 2015-08-12
 
diff --git a/src/V3LinkCells.cpp b/src/V3LinkCells.cpp
index ada7f12a2..6288909dc 100644
--- a/src/V3LinkCells.cpp
+++ b/src/V3LinkCells.cpp
@@ -348,14 +348,34 @@ private:
 	    // This is quite similar to how classes work; when unpacked classes are better supported
 	    // may remap interfaces to be more like a class.
 	    if (!nodep->hasIfaceVar()) {
-		string varName = nodep->name()+"__Viftop";  // V3LinkDot looks for this naming
-		AstIfaceRefDType* idtypep = new AstIfaceRefDType(nodep->fileline(), nodep->name(), nodep->modp()->name());
-		idtypep->cellp(nodep);  // Only set when real parent cell known
-		idtypep->ifacep(NULL);  // cellp overrides
-		AstVar* varp = new AstVar(nodep->fileline(), AstVarType::IFACEREF, varName, VFlagChildDType(), idtypep);
-		varp->isIfaceParent(true);
-		nodep->addNextHere(varp);
-		nodep->hasIfaceVar(true);
+		if (nodep->rangep()) {
+		    int count = nodep->rangep()->lsbConst();
+		    for (int i = 0; i < count; i++) {
+			string varName = nodep->name() + "__BRA__" + cvtToStr(i) + "__KET__" +
+			    "__Viftop";  // V3LinkDot looks for this naming
+			AstIfaceRefDType *idtypep = new AstIfaceRefDType(nodep->fileline(),
+									 nodep->name(),
+									 nodep->modp()->name());
+			idtypep->cellp(nodep);  // Only set when real parent cell known
+			idtypep->ifacep(NULL);  // cellp overrides
+			AstVar *varp = new AstVar(nodep->fileline(), AstVarType::IFACEREF, varName,
+						  VFlagChildDType(), idtypep);
+			varp->isIfaceParent(true);
+			nodep->addNextHere(varp);
+			nodep->hasIfaceVar(true);
+		    }
+		} else {
+		    string varName = nodep->name() + "__Viftop";  // V3LinkDot looks for this naming
+		    AstIfaceRefDType *idtypep = new AstIfaceRefDType(nodep->fileline(), nodep->name(),
+								     nodep->modp()->name());
+		    idtypep->cellp(nodep);  // Only set when real parent cell known
+		    idtypep->ifacep(NULL);  // cellp overrides
+		    AstVar *varp = new AstVar(nodep->fileline(), AstVarType::IFACEREF, varName,
+					      VFlagChildDType(), idtypep);
+		    varp->isIfaceParent(true);
+		    nodep->addNextHere(varp);
+		    nodep->hasIfaceVar(true);
+		}
 	    }
 	}
 	if (nodep->modp()) {
diff --git a/test_regress/t/t_array_interface.pl b/test_regress/t/t_array_interface.pl
new file mode 100755
index 000000000..f91289753
--- /dev/null
+++ b/test_regress/t/t_array_interface.pl
@@ -0,0 +1,18 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+    );
+
+execute (
+    check_finished=>1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_array_interface.v b/test_regress/t/t_array_interface.v
new file mode 100644
index 000000000..f2f67f0b7
--- /dev/null
+++ b/test_regress/t/t_array_interface.v
@@ -0,0 +1,28 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2015 by Johan Bjork.
+
+interface intf;
+    logic a;
+    modport source(output a);
+    modport sink(input a);
+endinterface
+
+module t
+#(
+    parameter N = 1
+)
+(   input [N-1:0] a_in,
+    output[N-1:0] a_out
+);
+    intf ifs[N-1:0] ();
+    logic   [N-1:0] a_q;
+
+    assign a_out = a_q;
+    assign ifs[0].a  = a_in[0];
+    initial begin
+       $write("*-* All Finished *-*\n");
+       $finish;
+    end
+endmodule