Changed TIMESCALEMOD from error into a warning. (#2838)

Changes

@@ -14,6 +14,7 @@ Verilator 4.201 devel
 **Minor:**
 
 * Add EOFNEWLINE warning when missing a newline at EOF.
+* Changed TIMESCALEMOD from error into a warning.
 * Verilated signals now use VlWide and VlPacked in place of C arrays.
 * Fix class unpacked-array compile error (#2774). [Iru Cai]
 * Fix exceeding command-line ar limit (#2834). [Yinan Xu]

bin/verilator

@@ -4885,16 +4885,18 @@ correctly.
 
 =item TIMESCALEMOD
 
-Error that `timescale is used in some but not all modules.
+Warns that `timescale is used in some but not all modules.  Recommend using
-Recommend using --timescale argument, or in front of all modules use:
+--timescale argument, or in front of all modules use:
 
    `include "timescale.vh"
 
 Then in that file set the timescale.
 
-This is an error due to IEEE specifications, but it may be disabled similar
+It may be disabled similar to other warnings.  Ignoring this warning may
-to warnings.  Ignoring this error may result in a module having an
+result in a module having an unexpected timescale.
-unexpected timescale.
+
+IEEE recommends this be an error, for that behavior use
+-Werror-TIMESCALEMOD.
 
 =item UNDRIVEN
 

src/V3Error.h

@@ -190,8 +190,7 @@ public:
     // Later -Werror- options may make more of these.
     bool pretendError() const {
         return (m_e == ASSIGNIN || m_e == BLKANDNBLK || m_e == BLKLOOPINIT || m_e == CONTASSREG
-                || m_e == IMPURE || m_e == PKGNODECL || m_e == PROCASSWIRE  //
+                || m_e == IMPURE || m_e == PKGNODECL || m_e == PROCASSWIRE);  // Says IEEE
-                || m_e == TIMESCALEMOD);  // Says IEEE
     }
     // Warnings to mention manual
     bool mentionManual() const {

src/V3LinkLevel.cpp

@@ -106,7 +106,7 @@ void V3LinkLevel::timescaling(const ModVec& mods) {
                 && !(VN_IS(nodep, Package) && VN_CAST(nodep, Package)->isDollarUnit())) {
                 nodep->v3warn(TIMESCALEMOD,
                               "Timescale missing on this module as other modules have "
-                              "it (IEEE 1800-2017 3.14.2.2)\n"
+                              "it (IEEE 1800-2017 3.14.2.3)\n"
                                   << nodep->warnContextPrimary() << '\n'
                                   << modTimedp->warnOther()
                                   << "... Location of module with timescale\n"

test_regress/t/t_timescale_lint_bad.out

@@ -1,7 +1,8 @@
-%Error-TIMESCALEMOD: t/t_timescale_lint_bad.v:7:8: Timescale missing on this module as other modules have it (IEEE 1800-2017 3.14.2.2)
+%Warning-TIMESCALEMOD: t/t_timescale_lint_bad.v:7:8: Timescale missing on this module as other modules have it (IEEE 1800-2017 3.14.2.3)
     7 | module pre_no_ts;
       |        ^~~~~~~~~
                        t/t_timescale_lint_bad.v:12:8: ... Location of module with timescale
    12 | module t;
       |        ^
+                       ... Use "/* verilator lint_off TIMESCALEMOD */" and lint_on around source to disable this message.
 %Error: Exiting due to