Fix error message when call task as a function (#3089).

Changes

@@ -13,6 +13,7 @@ Verilator 5.033 devel
 
 **Minor:**
 
+* Fix error message when call task as a function (#3089). [Matthew Ballance]
 * Fix V3Simulate constant reuse (#5709). [Geza Lore]
 * Fix man pages what-is section (#5710). [Ahmed El-Mahmoudy]
 * Fix pattern assignment to real inside struct (#5713).

src/V3LinkDot.cpp

@@ -2336,11 +2336,6 @@ class LinkDotResolveVisitor final : public VNVisitor {
         nodep->addStmtsp(superNewStmtp);
         return superNewStmtp;
     }
-    void taskFuncSwapCheck(AstNodeFTaskRef* nodep) {
-        if (nodep->taskp() && VN_IS(nodep->taskp(), Task) && VN_IS(nodep, FuncRef)) {
-            nodep->v3error("Illegal call of a task as a function: " << nodep->prettyNameQ());
-        }
-    }
     void checkNoDot(AstNode* nodep) {
         if (VL_UNLIKELY(m_ds.m_dotPos != DP_NONE)) {
             // UINFO(9, indent() << "ds=" << m_ds.ascii() << endl);
@@ -3779,7 +3774,6 @@ class LinkDotResolveVisitor final : public VNVisitor {
                     okSymp->cellErrorScopes(nodep);
                 }
             }
-            taskFuncSwapCheck(nodep);
         }
     }
     void visit(AstSelBit* nodep) override {

src/V3Width.cpp

@@ -3929,11 +3929,14 @@ class WidthVisitor final : public VNVisitor {
                     AstNodeExpr* argsp = nullptr;
                     if (nodep->pinsp()) argsp = nodep->pinsp()->unlinkFrBackWithNext();
                     AstNodeFTaskRef* newp = nullptr;
-                    if (VN_IS(ftaskp, Task)) {
+                    // We use m_vup to determine task or function, so that later error checks
-                        newp = new AstTaskRef{nodep->fileline(), VN_AS(ftaskp, Task), argsp};
+                    // for funcref->task and taskref->func will pick up properly
+                    if (!m_vup) {  // Called as task
+                        newp = new AstTaskRef{nodep->fileline(), nodep->name(), argsp};
                     } else {
-                        newp = new AstFuncRef{nodep->fileline(), VN_AS(ftaskp, Func), argsp};
+                        newp = new AstFuncRef{nodep->fileline(), nodep->name(), argsp};
                     }
+                    newp->taskp(ftaskp);  // Not passed above as might be func vs task mismatch
                     newp->classOrPackagep(classp);
                     nodep->replaceWith(newp);
                     VL_DO_DANGLING(nodep->deleteTree(), nodep);
@@ -3941,7 +3944,18 @@ class WidthVisitor final : public VNVisitor {
                     nodep->taskp(ftaskp);
                     nodep->dtypeFrom(ftaskp);
                     nodep->classOrPackagep(classp);
-                    if (VN_IS(ftaskp, Task)) nodep->dtypeSetVoid();
+                    if (VN_IS(ftaskp, Task)) {
+                        if (!m_vup) {
+                            nodep->dtypeSetVoid();
+                        } else {
+                            if (m_vup->prelim()) {
+                                nodep->v3error(
+                                    "Cannot call a task/void-function as a member function: "
+                                    << nodep->prettyNameQ());
+                            }
+                            nodep->dtypeSetVoid();
+                        }
+                    }
                     if (withp) nodep->addPinsp(withp);
                     processFTaskRefArgs(nodep);
                 }
@@ -5824,7 +5838,15 @@ class WidthVisitor final : public VNVisitor {
     }
     void visit(AstFuncRef* nodep) override {
         visit(static_cast<AstNodeFTaskRef*>(nodep));
-        nodep->dtypeFrom(nodep->taskp());
+        if (nodep->taskp() && VN_IS(nodep->taskp(), Task)) {
+            UASSERT_OBJ(m_vup, nodep, "Function reference where widthed expression expection");
+            if (m_vup->prelim())
+                nodep->v3error(
+                    "Cannot call a task/void-function as a function: " << nodep->prettyNameQ());
+            nodep->dtypeSetVoid();
+        } else {
+            nodep->dtypeFrom(nodep->taskp());
+        }
         if (nodep->fileline()->timingOn()) {
             AstNodeModule* const classp = nodep->classOrPackagep();
             if (nodep->name() == "self" && classp->name() == "process") {
@@ -6089,6 +6111,7 @@ class WidthVisitor final : public VNVisitor {
         processFTaskRefArgs(nodep);
         nodep->addPinsp(withp);
         nodep->didWidth(true);
+        // See steps that follow in visit(AstFuncRef*)
     }
     void visit(AstNodeProcedure* nodep) override {
         assertAtStatement(nodep);

test_regress/t/t_class_func_nvoid_bad.out

@@ -0,0 +1,25 @@
+%Error: t/t_class_func_nvoid_bad.v:47:11: Cannot call a task/void-function as a function: 'mod_fv'
+                                        : ... note: In instance 't'
+   47 |       if (mod_fv() == 10) $stop;   
+      |           ^~~~~~
+%Error: t/t_class_func_nvoid_bad.v:50:11: Cannot call a task/void-function as a function: 'mod_t'
+                                        : ... note: In instance 't'
+   50 |       if (mod_t() == 10) $stop;   
+      |           ^~~~~
+%Error: t/t_class_func_nvoid_bad.v:58:13: Cannot call a task/void-function as a member function: 'fv'
+                                        : ... note: In instance 't'
+   58 |       if (c.fv() == 10) $stop;   
+      |             ^~
+%Error: t/t_class_func_nvoid_bad.v:61:13: Cannot call a task/void-function as a member function: 't'
+                                        : ... note: In instance 't'
+   61 |       if (c.t() == 10) $stop;   
+      |             ^
+%Error: t/t_class_func_nvoid_bad.v:69:13: Cannot call a task/void-function as a function: 'sfv'
+                                        : ... note: In instance 't'
+   69 |       if (c.sfv() == 10) $stop;   
+      |             ^~~
+%Error: t/t_class_func_nvoid_bad.v:72:13: Cannot call a task/void-function as a function: 'st'
+                                        : ... note: In instance 't'
+   72 |       if (c.st() == 10) $stop;   
+      |             ^~
+%Error: Exiting due to

test_regress/t/t_class_func_nvoid_bad.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 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
+
+import vltest_bootstrap
+
+test.scenarios('linter')
+
+test.lint(fails=True, expect_filename=test.golden_filename)
+
+test.passes()

test_regress/t/t_class_func_nvoid_bad.v

@@ -0,0 +1,76 @@
+// 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
+
+
+class Cls;
+   function int fi();
+      return 10;
+   endfunction
+   function void fv();
+   endfunction
+   task t();
+   endtask
+   static function int sfi();
+      return 10;
+   endfunction
+   static function void sfv();
+   endfunction
+   static task st();
+   endtask
+endclass
+
+module t (/*AUTOARG*/);
+
+   function int mod_fi();
+      return 10;
+   endfunction
+   function void mod_fv();
+   endfunction
+   task mod_t();
+   endtask
+
+   initial begin
+      Cls c;
+      c = new;
+
+      // For test of calling function in void context, see t_func_void_bad.v
+
+      // Module
+      if (mod_fi() != 10) $stop;  // OK
+      void'(mod_fi());  // OK
+
+      mod_fv();  // Warn IGNOREDRETURN
+      void'(mod_fv());  // OK
+      if (mod_fv() == 10) $stop;  // Bad call of task as function
+
+      mod_t();  // OK
+      if (mod_t() == 10) $stop;  // Bad call of task as function
+
+      // Member functions
+      if (c.fi() != 10) $stop;  // OK
+      void'(c.fi());  // OK
+
+      c.fv();  // Ok
+      void'(c.fv());  // OK
+      if (c.fv() == 10) $stop;  // Bad
+
+      c.t();  // OK
+      if (c.t() == 10) $stop;  // Bad
+
+      // Static member functions
+      if (c.sfi() != 10) $stop;  // OK
+      void'(c.sfi());  // OK
+
+      c.sfv();  // Ok
+      void'(c.sfv());  // OK
+      if (c.sfv() == 10) $stop;  // Bad
+
+      c.st();  // OK
+      if (c.st() == 10) $stop;  // Bad
+
+      $stop;
+   end
+endmodule

test_regress/t/t_func_task_bad.out

@@ -1,4 +1,9 @@
-%Error: t/t_func_task_bad.v:10:11: Illegal call of a task as a function: 'task_as_func'
+%Error: t/t_func_task_bad.v:10:11: Cannot call a task/void-function as a function: 'task_as_func'
+                                 : ... note: In instance 't'
    10 |       if (task_as_func(1'b0)) $stop;
       |           ^~~~~~~~~~~~
+%Error: t/t_func_task_bad.v:10:7: Logical operator IF expects a non-complex data type on the If.
+                                : ... note: In instance 't'
+   10 |       if (task_as_func(1'b0)) $stop;
+      |       ^~
 %Error: Exiting due to

test_regress/t/t_func_void_bad.out

@@ -1,9 +1,12 @@
-%Warning-IGNOREDRETURN: t/t_func_void_bad.v:21:7: Ignoring return value of non-void function (IEEE 1800-2023 13.4.1)
+%Warning-IGNOREDRETURN: t/t_func_void_bad.v:24:7: Ignoring return value of non-void function (IEEE 1800-2023 13.4.1)
-   21 |       f1();   
+   24 |       f1();   
       |       ^~
                         ... For warning description see https://verilator.org/warn/IGNOREDRETURN?v=latest
                         ... Use "/* verilator lint_off IGNOREDRETURN */" and lint_on around source to disable this message.
-%Warning-IGNOREDRETURN: t/t_func_void_bad.v:24:9: Ignoring return value of non-void function (IEEE 1800-2023 13.4.1)
+%Warning-IGNOREDRETURN: t/t_func_void_bad.v:27:9: Ignoring return value of non-void function (IEEE 1800-2023 13.4.1)
-   24 |       c.fi();   
+   27 |       c.fi();   
       |         ^~
+%Warning-IGNOREDRETURN: t/t_func_void_bad.v:28:9: Ignoring return value of non-void function (IEEE 1800-2023 13.4.1)
+   28 |       c.sfi();   
+      |         ^~~
 %Error: Exiting due to

test_regress/t/t_func_void_bad.v

@@ -8,6 +8,9 @@ class Cls;
    function int fi();
       return 10;
    endfunction
+   static function int sfi();
+      return 10;
+   endfunction
 endclass
 
 module t;
@@ -22,6 +25,7 @@ module t;
       //
       c = new;
       c.fi();  // Bad - ignored result
+      c.sfi();  // Bad - ignored result
       //
       $write("*-* All Finished *-*\n");
       $finish;

test_regress/t/t_lint_implicit_func_bad.out

@@ -1,4 +1,5 @@
-%Error: t/t_lint_implicit_func_bad.v:12:11: Illegal call of a task as a function: 'imp_func_conflict'
+%Error: t/t_lint_implicit_func_bad.v:12:11: Cannot call a task/void-function as a function: 'imp_func_conflict'
+                                          : ... note: In instance 't'
    12 |    assign imp_func_conflict = 1'b1;
       |           ^~~~~~~~~~~~~~~~~
 %Error: Exiting due to