Show line/col for parsing exceptions in gen-s-parser (#2138)

3 files changed, 20 insertions, 2 deletions

diff --git a/scripts/gen-s-parser.py b/scripts/gen-s-parser.py
index 5e5ec494f..8329ae13b 100755
--- a/scripts/gen-s-parser.py
+++ b/scripts/gen-s-parser.py
@@ -528,7 +528,7 @@ def instruction_parser():
   emit(trie)
   printer.print_line("parse_error:")
   with printer.indent():
-    printer.print_line("throw ParseException(std::string(op));")
+    printer.print_line("throw ParseException(std::string(op), s.line, s.col);")
 
 
 def print_header():
diff --git a/src/gen-s-parser.inc b/src/gen-s-parser.inc
index 65a780b8b..2fd554107 100644
--- a/src/gen-s-parser.inc
+++ b/src/gen-s-parser.inc
@@ -2250,7 +2250,7 @@ switch (op[0]) {
   default: goto parse_error;
 }
 parse_error:
-  throw ParseException(std::string(op));
+  throw ParseException(std::string(op), s.line, s.col);
 #endif // INSTRUCTION_PARSER
 
 // clang-format on
diff --git a/test/unit/test_parsing_error.py b/test/unit/test_parsing_error.py
new file mode 100644
index 000000000..93aab1d16
--- /dev/null
+++ b/test/unit/test_parsing_error.py
@@ -0,0 +1,18 @@
+from scripts.test.shared import WASM_OPT, run_process
+from utils import BinaryenTestCase
+import os
+
+
+class ParsingErrorTest(BinaryenTestCase):
+  def test_parsing_error_msg(self):
+    module = '''
+    (module
+     (func $foo
+      (abc)
+     )
+    )
+    '''
+    p = run_process(WASM_OPT + ['--print', '-o', os.devnull], input=module,
+                    check=False, capture_output=True)
+    self.assertNotEqual(p.returncode, 0)
+    self.assertIn("parse exception: abc (at 4:6)", p.stderr)