Add the -Wimplicit-dimensions warning.

compiler.h

@@ -80,6 +80,10 @@ extern unsigned recursive_mod_limit;
 /* Implicit definitions of wires. */
 extern bool warn_implicit;
 
+/* Warn if dimensions of port or var/net are implicitly taken from
+   the input/output/inout declaration. */
+extern bool warn_implicit_dimensions;
+
 /* inherit timescales across files. */
 extern bool warn_timescale;
 

driver/main.c

@@ -496,6 +496,7 @@ static void process_warning_switch(const char*name)
       if (strcmp(name,"all") == 0) {
 	    process_warning_switch("anachronisms");
 	    process_warning_switch("implicit");
+	    process_warning_switch("implicit-dimensions");
 	    process_warning_switch("portbind");
 	    process_warning_switch("select-range");
 	    process_warning_switch("timescale");
@@ -509,6 +510,9 @@ static void process_warning_switch(const char*name)
       } else if (strcmp(name,"implicit") == 0) {
 	    if (! strchr(warning_flags, 'i'))
 		  strcat(warning_flags, "i");
+      } else if (strcmp(name,"implicit-dimensions") == 0) {
+	    if (! strchr(warning_flags, 'd'))
+		  strcat(warning_flags, "d");
       } else if (strcmp(name,"portbind") == 0) {
 	    if (! strchr(warning_flags, 'p'))
 		  strcat(warning_flags, "p");
@@ -547,6 +551,12 @@ static void process_warning_switch(const char*name)
 		  cp[0] = cp[1];
 		  cp += 1;
 	    }
+      } else if (strcmp(name,"no-implicit-dimensions") == 0) {
+	    char*cp = strchr(warning_flags, 'd');
+	    if (cp) while (*cp) {
+		  cp[0] = cp[1];
+		  cp += 1;
+	    }
       } else if (strcmp(name,"no-portbind") == 0) {
 	    char*cp = strchr(warning_flags, 'p');
 	    if (cp) while (*cp) {

elab_sig.cc

@@ -976,6 +976,23 @@ NetNet* PWire::elaborate_sig(Design*des, NetScope*scope) const
       }
 
       if (port_set_ || net_set_) {
+
+	    if (warn_implicit_dimensions
+		&& port_set_ && net_set_
+		&& net_.empty() && !port_.empty()) {
+		  cerr << get_fileline() << ": warning: "
+		       << "var/net declaration of " << basename()
+		       << " inherits dimensions from port declaration." << endl;
+	    }
+
+	    if (warn_implicit_dimensions
+		&& port_set_ && net_set_
+		&& port_.empty() && net_.empty()) {
+		  cerr << get_fileline() << ": warning: "
+		       << "Port declaration of " << basename()
+		       << " inherits dimensions from var/net." << endl;
+	    }
+
 	    bool bad_range = false;
 	    vector<netrange_t> plist, nlist;
 	    /* If they exist get the port definition MSB and LSB */

main.cc

@@ -153,6 +153,7 @@ FILE *depend_file = NULL;
  * These are the warning enable flags.
  */
 bool warn_implicit  = false;
+bool warn_implicit_dimensions = false;
 bool warn_timescale = false;
 bool warn_portbinding = false;
 bool warn_inf_loop = false;
@@ -682,6 +683,9 @@ static void read_iconfig_file(const char*ipath)
 		      case 'i':
 			warn_implicit = true;
 			break;
+		      case 'd':
+			warn_implicit_dimensions = true;
+			break;
 		      case 'l':
 			warn_inf_loop = true;
 			break;

scripts/devel-stub.conf

@@ -15,7 +15,7 @@ iwidth:32
 sys_func:vpi/system.sft
 sys_func:vpi/v2005_math.sft
 sys_func:vpi/va_math.sft
-warnings:afilnpstv
+warnings:adfilnpstv
 debug:eval_tree
 debug:elaborate
 debug:emit