Improve E_UNSUPPORTED warning messages (#7329)

src/V3LinkInc.cpp

@@ -292,7 +292,9 @@ class LinkIncVisitor final : public VNVisitor {
     void prepost_expr_visit(AstNodeTriop* nodep) {
         iterateChildren(nodep);
         if (m_unsupportedHere) {
-            nodep->v3warn(E_UNSUPPORTED, "Unsupported: Incrementation in this context.");
+            nodep->v3warn(E_UNSUPPORTED,
+                         "Unsupported: Pre/post increment/decrement operator"
+                         " within a logical expression (&&, ||, ?:, etc.)");
             return;
         }
         AstNodeExpr* const readp = nodep->rhsp();

src/V3Timing.cpp

@@ -1046,7 +1046,9 @@ class TimingControlVisitor final : public VNVisitor {
         // Do not allow waiting on local named events, as they get enqueued for clearing, but can
         // go out of scope before that happens
         if (!nodep->sentreep()) {
-            nodep->v3warn(E_UNSUPPORTED, "Unsupported: no sense equation (@*)");
+            nodep->v3warn(E_UNSUPPORTED,
+                         "Unsupported: Event control with implicit sensitivity (@*)"
+                         " in this context; use an explicit sensitivity list instead");
             VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);
             return;
         }

src/V3Width.cpp

@@ -1666,7 +1666,8 @@ class WidthVisitor final : public VNVisitor {
             if (VN_IS(selp->fromp()->dtypep()->skipRefp(), QueueDType)) return;
         }
         // queue_slice[#:$] and queue_bitsel[$] etc handled in V3WidthSel
-        nodep->v3warn(E_UNSUPPORTED, "Unsupported/illegal unbounded ('$') in this context.");
+        nodep->v3warn(E_UNSUPPORTED,
+                     "Unsupported: Unbounded ('$') outside of queue or string operations");
     }
     void visit(AstInferredDisable* nodep) override {
         assertAtExpr(nodep);

test_regress/t/t_event_control_star.out

@@ -1,4 +1,4 @@
-%Error-UNSUPPORTED: t/t_event_control_star.v:19:5: Unsupported: no sense equation (@*)
+%Error-UNSUPPORTED: t/t_event_control_star.v:19:5: Unsupported: Event control with implicit sensitivity (@*) in this context; use an explicit sensitivity list instead
    19 |     @* a = c;   
       |     ^
                     ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest

test_regress/t/t_increment_bad.out

@@ -1,23 +1,23 @@
-%Error-UNSUPPORTED: t/t_increment_bad.v:19:29: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:19:29: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    19 |     if (0 && test_string[pos++] != "e");
       |                             ^~
                     ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
-%Error-UNSUPPORTED: t/t_increment_bad.v:20:17: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:20:17: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    20 |     if (1 || pos-- != 1);
       |                 ^~
-%Error-UNSUPPORTED: t/t_increment_bad.v:22:15: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:22:15: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    22 |     if (a <-> --b);
       |               ^~
-%Error-UNSUPPORTED: t/t_increment_bad.v:23:14: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:23:14: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    23 |     if (0 -> ++b);
       |              ^~
-%Error-UNSUPPORTED: t/t_increment_bad.v:25:22: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:25:22: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    25 |     pos = (a > 0) ? a++ : --b;
       |                      ^~
-%Error-UNSUPPORTED: t/t_increment_bad.v:25:27: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:25:27: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    25 |     pos = (a > 0) ? a++ : --b;
       |                           ^~
-%Error-UNSUPPORTED: t/t_increment_bad.v:30:36: Unsupported: Incrementation in this context.
+%Error-UNSUPPORTED: t/t_increment_bad.v:30:36: Unsupported: Pre/post increment/decrement operator within a logical expression (&&, ||, ?:, etc.)
    30 |   assert property (@(posedge clk) a++ >= 0);
       |                                    ^~
 %Error: Exiting due to

test_regress/t/t_unbounded_bad.out

@@ -1,4 +1,4 @@
-%Error-UNSUPPORTED: t/t_unbounded_bad.v:9:9: Unsupported/illegal unbounded ('$') in this context.
+%Error-UNSUPPORTED: t/t_unbounded_bad.v:9:9: Unsupported: Unbounded ('$') outside of queue or string operations
                                            : ... note: In instance 't'
     9 |     if ($) $stop;
       |         ^