diff --git a/tgt-vhdl/expr.cc b/tgt-vhdl/expr.cc
index ead20f2bf..80b9a05bc 100644
--- a/tgt-vhdl/expr.cc
+++ b/tgt-vhdl/expr.cc
@@ -40,7 +40,11 @@ static vhdl_expr *translate_string(ivl_expr_t e)
 static vhdl_expr *translate_signal(ivl_expr_t e)
 {
    ivl_signal_t sig = ivl_expr_signal(e);
-   return new vhdl_var_ref(ivl_signal_basename(sig));
+
+   // Assume all signals are single bits at the moment
+   vhdl_type *type = vhdl_scalar_type::std_logic();
+   
+   return new vhdl_var_ref(ivl_signal_basename(sig), type);
 }
 
 /*
diff --git a/tgt-vhdl/stmt.cc b/tgt-vhdl/stmt.cc
index bdeb5d2e7..c42110707 100644
--- a/tgt-vhdl/stmt.cc
+++ b/tgt-vhdl/stmt.cc
@@ -70,7 +70,9 @@ static int draw_stask_display(vhdl_process *proc, ivl_statement_t stmt)
          e = new vhdl_const_string(" ");
 
       vhdl_pcall_stmt *write = new vhdl_pcall_stmt("Write");
-      write->add_expr(new vhdl_var_ref(display_line));
+      vhdl_var_ref *ref =
+         new vhdl_var_ref(display_line, vhdl_scalar_type::line());
+      write->add_expr(ref);
       write->add_expr(e);
 
       proc->add_stmt(write);
@@ -78,8 +80,12 @@ static int draw_stask_display(vhdl_process *proc, ivl_statement_t stmt)
 
    // WriteLine(Output, Verilog_Display_Line)
    vhdl_pcall_stmt *write_line = new vhdl_pcall_stmt("WriteLine");
-   write_line->add_expr(new vhdl_var_ref("std.textio.Output"));
-   write_line->add_expr(new vhdl_var_ref(display_line));
+   vhdl_var_ref *output_ref =
+      new vhdl_var_ref("std.textio.Output", new vhdl_scalar_type("File"));
+   write_line->add_expr(output_ref);
+   vhdl_var_ref *ref =
+      new vhdl_var_ref(display_line, vhdl_scalar_type::line());
+   write_line->add_expr(ref);
    proc->add_stmt(write_line);
    
    return 0;
diff --git a/tgt-vhdl/vhdl_element.cc b/tgt-vhdl/vhdl_element.cc
index 648cde01d..ab3d49b14 100644
--- a/tgt-vhdl/vhdl_element.cc
+++ b/tgt-vhdl/vhdl_element.cc
@@ -343,6 +343,21 @@ void vhdl_wait_stmt::emit(std::ofstream &of, int level) const
    of << "wait;";
 }
 
+vhdl_scalar_type *vhdl_scalar_type::std_logic()
+{
+   return new vhdl_scalar_type("std_logic");
+}
+
+vhdl_scalar_type *vhdl_scalar_type::string()
+{
+   return new vhdl_scalar_type("String");
+}
+
+vhdl_scalar_type *vhdl_scalar_type::line()
+{
+   return new vhdl_scalar_type("Line");
+}
+
 void vhdl_scalar_type::emit(std::ofstream &of, int level) const
 {
    of << name_;
@@ -374,6 +389,11 @@ void vhdl_signal_decl::emit(std::ofstream &of, int level) const
    emit_comment(of, level, true);
 }
 
+vhdl_expr::~vhdl_expr()
+{
+   delete type_;
+}
+
 void vhdl_expr_list::add_expr(vhdl_expr *e)
 {
    exprs_.push_back(e);
diff --git a/tgt-vhdl/vhdl_element.hh b/tgt-vhdl/vhdl_element.hh
index 3e14a2bd6..80029e585 100644
--- a/tgt-vhdl/vhdl_element.hh
+++ b/tgt-vhdl/vhdl_element.hh
@@ -64,13 +64,21 @@ public:
    vhdl_scalar_type(const char *name) : name_(name) {}
 
    void emit(std::ofstream &of, int level) const;
+
+   // Common types
+   static vhdl_scalar_type *std_logic();
+   static vhdl_scalar_type *string();
+   static vhdl_scalar_type *line();
 private:
    std::string name_;
 };
 
 class vhdl_expr : public vhdl_element {
 public:
-   virtual ~vhdl_expr() {}
+   vhdl_expr(vhdl_type* type) : type_(type) {}
+   virtual ~vhdl_expr();
+private:
+   vhdl_type *type_;
 };
 
 /*
@@ -78,7 +86,8 @@ public:
  */
 class vhdl_var_ref : public vhdl_expr {
 public:
-   vhdl_var_ref(const char *name) : name_(name) {}
+   vhdl_var_ref(const char *name, vhdl_type *type)
+      : vhdl_expr(type), name_(name) {}
 
    void emit(std::ofstream &of, int level) const;
 private:
@@ -87,7 +96,8 @@ private:
 
 class vhdl_const_string : public vhdl_expr {
 public:
-   vhdl_const_string(const char *value) : value_(value) {}
+   vhdl_const_string(const char *value)
+      : vhdl_expr(vhdl_scalar_type::string()), value_(value) {}
 
    void emit(std::ofstream &of, int level) const;
 private: