Parser: Move disable fork and wait fork down into elaborate stage

src/V3AstNodes.h

@@ -4337,6 +4337,22 @@ public:
     }
 };
 
+class AstDisableFork : public AstNodeStmt {
+    // A "disable fork" statement
+public:
+    AstDisableFork(FileLine* fl)
+        : ASTGEN_SUPER(fl) {}
+    ASTNODE_NODE_FUNCS(DisableFork)
+};
+
+class AstWaitFork : public AstNodeStmt {
+    // A "wait fork" statement
+public:
+    AstWaitFork(FileLine* fl)
+        : ASTGEN_SUPER(fl) {}
+    ASTNODE_NODE_FUNCS(WaitFork)
+};
+
 class AstReturn : public AstNodeStmt {
 public:
     explicit AstReturn(FileLine* fl, AstNode* lhsp = NULL)

src/V3Width.cpp

@@ -568,6 +568,14 @@ private:
             // TBD might support only normal join, if so complain about other join flavors
         }
     }
+    virtual void visit(AstDisableFork* nodep) VL_OVERRIDE {
+        nodep->v3warn(E_UNSUPPORTED, "Unsupported: disable fork statements");
+        VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+    }
+    virtual void visit(AstWaitFork* nodep) VL_OVERRIDE {
+        nodep->v3warn(E_UNSUPPORTED, "Unsupported: wait fork statements");
+        VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+    }
     virtual void visit(AstToLowerN* nodep) VL_OVERRIDE {
         if (m_vup->prelim()) {
             iterateCheckString(nodep, "LHS", nodep->lhsp(), BOTH);

src/verilog.y

@@ -3039,7 +3039,7 @@ statement_item<nodep>:		// IEEE: statement_item
 	//
 	//			// IEEE: disable_statement
 	|	yDISABLE idAny/*hierarchical_identifier-task_or_block*/ ';'	{ $$ = new AstDisable($1,*$2); }
-	|	yDISABLE yFORK ';'			{ $$ = NULL; BBUNSUP($1, "Unsupported: disable fork statements"); }
+	|	yDISABLE yFORK ';'			{ $$ = new AstDisableFork($1); }
 	//			// IEEE: event_trigger
 	|	yP_MINUSGT idDotted/*hierarchical_identifier-event*/ ';'
 			{ // AssignDly because we don't have stratified queue, and need to
@@ -3080,7 +3080,7 @@ statement_item<nodep>:		// IEEE: statement_item
 	//
 	//			// IEEE: wait_statement
 	|	yWAIT '(' expr ')' stmtBlock		{ $$ = NULL; BBUNSUP($1, "Unsupported: wait statements"); }
-	|	yWAIT yFORK ';'				{ $$ = NULL; BBUNSUP($1, "Unsupported: wait fork statements"); }
+	|	yWAIT yFORK ';'				{ $$ = new AstWaitFork($1); }
 	//UNSUP	yWAIT_ORDER '(' hierarchical_identifierList ')' action_block	{ UNSUP }
 	//
 	//			// IEEE: procedural_assertion_statement

test_regress/t/t_fork_disable.out

@@ -0,0 +1,13 @@
+%Error-UNSUPPORTED: t/t_fork_disable.v:12:7: Unsupported: fork statements
+                                           : ... In instance t
+   12 |       fork
+      |       ^~~~
+%Error-UNSUPPORTED: t/t_fork_disable.v:16:7: Unsupported: disable fork statements
+                                           : ... In instance t
+   16 |       disable fork;
+      |       ^~~~~~~
+%Error-UNSUPPORTED: t/t_fork_disable.v:17:7: Unsupported: wait fork statements
+                                           : ... In instance t
+   17 |       wait fork;
+      |       ^~~~
+%Error: Exiting due to

test_regress/t/t_fork_disable.pl

@@ -0,0 +1,20 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2019 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.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(linter => 1);
+
+lint(
+    verilator_flags2 => ['--lint-only'],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_fork_disable.v

@@ -0,0 +1,22 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+
+   logic never;
+
+   initial begin
+      fork
+         #10;
+         #10;
+      join_none
+      disable fork;
+      wait fork;
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule