skip start of block before looking for its end

CHANGELOG.md

@@ -8,6 +8,9 @@
   static prefixes, which could cause deep recursion and run out of memory on
   some designs
 * Fixed unneeded scoping of constant function calls used in type lookups
+* `/*/` is no longer interpreted as a self-closing block comment, e.g.,
+  `$display("a"/*/,"b"/* */);` previously printed "ab", but now prints "a"
+
 
 ### New Features
 

src/Language/SystemVerilog/Parser/Preprocess.hs

@@ -545,7 +545,10 @@ preprocessInput = do
     macroStack <- getMacroStack
     case str of
         '/' : '/' : _ -> removeThrough "\n"
-        '/' : '*' : _ -> removeThrough "*/"
+        '/' : '*' : _ ->
+            -- prevent treating `/*/` as self-closing
+            takeChar >> takeChar >>
+            removeThrough "*/"
         '`' : '"' : _ -> handleBacktickString
         '"' : _ -> handleString
         '/' : '`' : '`' : '*' : _ ->

test/lex/block_comment.sv

@@ -0,0 +1,7 @@
+module top;
+    /*test*/
+    /*/test*/
+    /*test/*/
+    /*/test/*/
+    initial $display("foo"/*/,"bar"/*/);
+endmodule

test/lex/block_comment.v

@@ -0,0 +1,3 @@
+module top;
+    initial $display("foo");
+endmodule