reset the default_nettype to wire at the end of the generated verilog (#3005)

Author: jergk

changelog/2025-09-05T19_03_39+02_00_implicit_nets

@@ -0,0 +1 @@
+CHANGED: when generating (System)Verilog, Clash now resets the default net type from none to the verilog default after the generated module

clash-lib/src/Clash/Backend/SystemVerilog.hs

@@ -228,14 +228,17 @@ genSystemVerilog opts _ sp seen us c = do
   where
     cName   = componentName c
     verilog = commentHeader <> line <>
-              nettype <> line <>
+              nettypeNone <> line <>
               timescale <> line <>
-              module_ c
+              module_ c <> line <>
+              nettypeDefault
+
     commentHeader
          = "/* AUTOMATICALLY GENERATED SYSTEMVERILOG-2005 SOURCE CODE."
       <> line <> "** GENERATED BY CLASH " <> string (Text.pack clashVer) <> ". DO NOT MODIFY."
       <> line <> "*/"
-    nettype = "`default_nettype none"
+    nettypeNone = "`default_nettype none"
+    nettypeDefault = "`default_nettype wire"
     timescale = "`timescale 100fs/" <> string (Text.pack precision)
     precision = periodToString (opt_timescalePrecision opts)
 

clash-lib/src/Clash/Backend/Verilog.hs

@@ -225,7 +225,11 @@ genVerilog opts  _ sp seen usage c = do
       usages .= usage
       setSrcSpan sp
 
-    v    <- commentHeader <> line <> nettype <> line <> timescale <> line <> module_ c
+    v    <- commentHeader <> line <>
+            nettypeNone <> line <>
+            timescale <> line <>
+            module_ c <> line <>
+            nettypeDefault
     incs <- Ap $ use includes
     return ((TextS.unpack (Id.toText cName), v), incs)
   where
@@ -234,7 +238,8 @@ genVerilog opts  _ sp seen usage c = do
          = "/* AUTOMATICALLY GENERATED VERILOG-2001 SOURCE CODE."
       <> line <> "** GENERATED BY CLASH " <> string (Text.pack clashVer) <> ". DO NOT MODIFY."
       <> line <> "*/"
-    nettype = "`default_nettype none"
+    nettypeNone = "`default_nettype none"
+    nettypeDefault = "`default_nettype wire"
     timescale = "`timescale 100fs/" <> string (Text.pack precision)
     precision = periodToString (opt_timescalePrecision opts)