Detect and complain about some constructor chain errors

This.new is not allowed.

super.new beyond the first statement is not allowed.

And while I'm at it, clean up the use of "@" and "#" in
the code as tokens for this and super.

elab_expr.cc

@@ -2601,7 +2601,7 @@ NetExpr* PECallFunction::elaborate_expr_method_(Design*des, NetScope*scope,
 	/* Add the implicit this reference when requested. */
       if (add_this_flag) {
 	    assert(use_path.empty());
-	    use_path.push_front(name_component_t(perm_string::literal("@")));
+	    use_path.push_front(name_component_t(perm_string::literal(THIS_TOKEN)));
       }
 
 	// If there is no object to the left of the method name, then
@@ -3906,7 +3906,7 @@ NetExpr* PEIdent::elaborate_expr_class_member_(Design*des, NetScope*scope,
       NetScope*scope_method = find_method_containing_scope(*this, scope);
       ivl_assert(*this, scope_method);
 
-      NetNet*this_net = scope_method->find_signal(perm_string::literal("@"));
+      NetNet*this_net = scope_method->find_signal(perm_string::literal(THIS_TOKEN));
       if (this_net == 0) {
 	    cerr << get_fileline() << ": internal error: "
 		 << "Unable to find 'this' port of " << scope_path(scope_method)
@@ -5766,7 +5766,7 @@ NetExpr* PENewClass::elaborate_expr_constructor_(Design*des, NetScope*scope,
 
 	      // The return value of the initializer is the "this"
 	      // variable, instead of the "new&" scope name.
-	    NetNet*res1 = new1_scope->find_signal(perm_string::literal("@"));
+	    NetNet*res1 = new1_scope->find_signal(perm_string::literal(THIS_TOKEN));
 	    ivl_assert(*this, res1);
 
 	    NetESignal*eres = new NetESignal(res1);
@@ -5853,7 +5853,7 @@ NetExpr* PENewClass::elaborate_expr_constructor_(Design*des, NetScope*scope,
 
 	// The return value for the constructor is actually the "this"
 	// variable, instead of the "new" scope name.
-      NetNet*res = new_scope->find_signal(perm_string::literal("@"));
+      NetNet*res = new_scope->find_signal(perm_string::literal(THIS_TOKEN));
       ivl_assert(*this, res);
 
       NetESignal*eres = new NetESignal(res);

elab_lval.cc

@@ -378,7 +378,7 @@ NetAssign_* PEIdent::elaborate_lval_method_class_member_(Design*des,
       NetScope*scope_method = find_method_containing_scope(*this, scope);
       ivl_assert(*this, scope_method);
 
-      NetNet*this_net = scope_method->find_signal(perm_string::literal("@"));
+      NetNet*this_net = scope_method->find_signal(perm_string::literal(THIS_TOKEN));
       if (this_net == 0) {
 	    cerr << get_fileline() << ": internal error: "
 		 << "Unable to find 'this' port of " << scope_path(scope_method)

elab_sig.cc

@@ -578,10 +578,10 @@ void PFunction::elaborate_sig(Design*des, NetScope*scope) const
 	      // source code for the definition may be:
 	      //   function new(...);
 	      //   endfunction
-	      // In this case, the "@" port is the synthetic "this"
-	      // argument and we also use it as a return value at the
-	      // same time.
-	    ret_sig = scope->find_signal(perm_string::literal("@"));
+	      // In this case, the "@" port (THIS_TOKEN) is the synthetic
+	      // "this" argument and we also use it as a return value at
+	      // the same time.
+	    ret_sig = scope->find_signal(perm_string::literal(THIS_TOKEN));
 	    ivl_assert(*this, ret_sig);
 
 	    if (debug_elaborate)

elaborate.cc

@@ -3002,6 +3002,25 @@ NetProc* PBlock::elaborate(Design*des, NetScope*scope) const
 
       for (unsigned idx = 0 ;  idx < list_.size() ;  idx += 1) {
 	    assert(list_[idx]);
+
+	      // Detect the error that a super.new() statement is in the
+	      // midst of a block. Report the error. Continue on with the
+	      // elaboration so that other errors might be found.
+	    if (PChainConstructor*supernew = dynamic_cast<PChainConstructor*> (list_[idx])) {
+	          if (debug_elaborate) {
+		        cerr << get_fileline() << ": PBlock::elaborate: "
+			     << "Found super.new statement, idx=" << idx << ", "
+			     << " at " << supernew->get_fileline() << "."
+			     << endl;
+		  }
+		  if (idx > 0) {
+		        des->errors += 1;
+			cerr << supernew->get_fileline() << ": error: "
+			     << "super.new(...) must be the first statement in a block."
+			     << endl;
+		  }
+	    }
+
 	    NetProc*tmp = list_[idx]->elaborate(des, nscope);
 	      // If the statement fails to elaborate, then simply
 	      // ignore it. Presumably, the elaborate for the
@@ -3266,7 +3285,7 @@ NetProc* PChainConstructor::elaborate(Design*des, NetScope*scope) const
 
 	// Need the "this" variable for the current constructor. We're
 	// going to pass this to the chained constructor.
-      NetNet*var_this = scope->find_signal(perm_string::literal("@"));
+      NetNet*var_this = scope->find_signal(perm_string::literal(THIS_TOKEN));
 
 	// If super.new is an implicit constructor, then there are no
 	// arguments (other than "this" to worry about, so make a
@@ -3728,7 +3747,7 @@ NetProc* PCallTask::elaborate_method_(Design*des, NetScope*scope,
 	/* Add the implicit this reference when requested. */
       if (add_this_flag) {
 	    assert(use_path.empty());
-	    use_path.push_front(name_component_t(perm_string::literal("@")));
+	    use_path.push_front(name_component_t(perm_string::literal(THIS_TOKEN)));
       }
 
 	// There is no signal to search for so this cannot be a method.

parse.y

@@ -68,7 +68,7 @@ static LexicalScope::lifetime_t var_lifetime;
 
 static pform_name_t* pform_create_this(void)
 {
-      name_component_t name (perm_string::literal("@"));
+      name_component_t name (perm_string::literal(THIS_TOKEN));
       pform_name_t*res = new pform_name_t;
       res->push_back(name);
       return res;
@@ -76,7 +76,7 @@ static pform_name_t* pform_create_this(void)
 
 static pform_name_t* pform_create_super(void)
 {
-      name_component_t name (perm_string::literal("#"));
+      name_component_t name (perm_string::literal(SUPER_TOKEN));
       pform_name_t*res = new pform_name_t;
       res->push_back(name);
       return res;
@@ -6897,6 +6897,9 @@ statement_item /* This is roughly statement_item in the LRM */
   | implicit_class_handle '.' K_new '(' expression_list_with_nuls ')' ';'
       { PChainConstructor*tmp = new PChainConstructor(*$5);
 	FILE_NAME(tmp, @3);
+	if (peek_head_name(*$1) == THIS_TOKEN) {
+	  yyerror(@1, "error: this.new is invalid syntax. Did you mean super.new?");
+	}
 	delete $1;
 	$$ = tmp;
       }

pform_pclass.cc

@@ -109,7 +109,7 @@ void pform_set_this_class(const struct vlltype&loc, PTaskFunc*net)
 	    return;
 
       list<perm_string>*this_name = new list<perm_string>;
-      this_name->push_back(perm_string::literal("@"));
+      this_name->push_back(perm_string::literal(THIS_TOKEN));
       vector<pform_tf_port_t>*this_port = pform_make_task_ports(loc,
 						       NetNet::PINPUT,
 						       pform_cur_class->type,

pform_types.h

@@ -381,6 +381,14 @@ inline perm_string peek_tail_name(const pform_name_t&that)
       return that.back().name;
 }
 
+/*
+ * In pform names, the "super" and "this" keywords are converted to
+ * These tokens so that they don't interfere with the namespace and
+ * are handled specially.
+ */
+# define SUPER_TOKEN "#"
+# define THIS_TOKEN  "@"
+
 extern std::ostream& operator<< (std::ostream&out, const pform_name_t&);
 extern std::ostream& operator<< (std::ostream&out, const name_component_t&that);
 extern std::ostream& operator<< (std::ostream&out, const index_component_t&that);