diff --git a/Changes b/Changes
index 10eab753d..332753d5c 100644
--- a/Changes
+++ b/Changes
@@ -5,7 +5,9 @@ indicates the contributor was also the author of the fix; Thanks!
 
 * Verilator 3.869 devel
 
-****  Suppress COMBDLY when inside always_latch, bug854. [Iztok Jeras]
+****  Suppress COMBDLY when inside always_latch, bug864. [Iztok Jeras]
+
+****  Support cast operator with expression size, bug865. [Iztok Jeras]
 
 
 * Verilator 3.868 2014-12-20
diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index a33d7aef7..b6761847a 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -3485,6 +3485,21 @@ public:
     AstNodeDType* childDTypep() const { return op2p()->castNodeDType(); }
 };
 
+class AstCastParse : public AstNode {
+    // Cast to appropriate type, where we haven't determined yet what the data type is
+public:
+    AstCastParse(FileLine* fl, AstNode* lhsp, AstNode* dtp) : AstNode(fl) {
+	setOp1p(lhsp); setOp2p(dtp);
+    }
+    ASTNODE_NODE_FUNCS(CastParse, CASTPARSE)
+    virtual string emitVerilog() { return "((%d)'(%l))"; }
+    virtual string emitC() { V3ERROR_NA; return ""; }
+    virtual bool cleanOut() { V3ERROR_NA; return true;} virtual bool cleanLhs() {return true;}
+    virtual bool sizeMattersLhs() {return false;}
+    AstNode* lhsp() const { return op1p(); }
+    AstNode* dtp() const { return op2p(); }
+};
+
 class AstCastSize : public AstNode {
     // Cast to specific size; signed/twostate inherited from lower element per IEEE
 public:
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index bb77134a7..3cba1036f 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -945,6 +945,21 @@ private:
 	nodep->iterateChildren(*this);
 	nodep->dtypep(iterateEditDTypep(nodep, nodep->subDTypep()));
     }
+    virtual void visit(AstCastParse* nodep, AstNUser* vup) {
+	// nodep->dtp could be data type, or a primary_constant
+	// Don't iterate lhsp, will deal with that once convert the type
+	V3Const::constifyParamsEdit(nodep->dtp()); // itemp may change
+	if (AstConst* constp = nodep->dtp()->castConst()) {
+	    constp->unlinkFrBack();
+	    AstNode* newp = new AstCastSize(nodep->fileline(), nodep->lhsp()->unlinkFrBack(), constp);
+	    nodep->replaceWith(newp);
+	    pushDeletep(nodep); nodep=NULL;
+	    newp->accept(*this,vup);
+	} else {
+	    nodep->v3error("Unsupported: Cast to "<<nodep->dtp()->prettyTypeName());
+	    nodep->replaceWith(nodep->lhsp()->unlinkFrBack());
+	}
+    }
     virtual void visit(AstCast* nodep, AstNUser* vup) {
 	if (nodep->childDTypep()) nodep->dtypep(moveChildDTypeEdit(nodep));
 	nodep->dtypep(iterateEditDTypep(nodep, nodep->dtypep()));
diff --git a/src/verilog.y b/src/verilog.y
index d77a53d6c..c3329e8d3 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -2977,8 +2977,7 @@ expr<nodep>:			// IEEE: part of expression/constant_expression/primary
 	|	yUNSIGNED    yP_TICK '(' expr ')'	{ $$ = new AstUnsigned($1,$4); }
 	//			// Spec only allows primary with addition of a type reference
 	//			// We'll be more general, and later assert LHS was a type.
-	//UNSUP	~l~expr yP_TICK '(' expr ')'		{ UNSUP }
-	|	yaINTNUM     yP_TICK '(' expr ')'	{ $$ = new AstCastSize($2,$4,new AstConst($1->fileline(),*$1)); }
+	|	~l~expr      yP_TICK '(' expr ')'	{ $$ = new AstCastParse($2,$4,$1); }
 	//
 	//			// IEEE: assignment_pattern_expression
 	//			// IEEE: streaming_concatenation
diff --git a/test_regress/t/t_cast.v b/test_regress/t/t_cast.v
index cda5ed171..5f23ff48b 100644
--- a/test_regress/t/t_cast.v
+++ b/test_regress/t/t_cast.v
@@ -11,6 +11,7 @@ module t;
    mc_t o;
 
    logic [15:0] allones = 16'hffff;
+   parameter FOUR = 4;
 
    initial begin
       if (4'shf > 4'sh0) $stop;
@@ -18,6 +19,11 @@ module t;
       if (4'hf < 4'h0) $stop;
       if (unsigned'(4'shf) < 4'h0) $stop;
       if (4'(allones) !== 4'hf) $stop;
+      if (6'(allones) !== 6'h3f) $stop;
+      if ((4)'(allones) !== 4'hf) $stop;
+      if ((4+2)'(allones) !== 6'h3f) $stop;
+      if ((4-2)'(allones) !== 2'h3) $stop;
+      if ((FOUR+2)'(allones) !== 6'h3f) $stop;
 
       o = tocast_t'(4'b1);
       if (o != 4'b1) $stop;