diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 009e6b109385..f366f9e29ca3 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -6429,8 +6429,10 @@ template <typename ParseHandler>
 bool
 Parser<ParseHandler>::argumentList(Node listNode, bool *isSpread)
 {
-    if (tokenStream.matchToken(TOK_RP, TokenStream::Operand))
+    if (tokenStream.matchToken(TOK_RP, TokenStream::Operand)) {
+        handler.setEndPosition(listNode, pos().end);
         return true;
+    }
 
     uint32_t startYieldOffset = pc->lastYieldOffset;
     bool arg0 = true;
@@ -6483,6 +6485,7 @@ Parser<ParseHandler>::argumentList(Node listNode, bool *isSpread)
         report(ParseError, false, null(), JSMSG_PAREN_AFTER_ARGS);
         return false;
     }
+    handler.setEndPosition(listNode, pos().end);
     return true;
 }
 
diff --git a/js/src/jit-test/tests/parser/bug-975484.js b/js/src/jit-test/tests/parser/bug-975484.js
new file mode 100644
index 000000000000..b164492240ff
--- /dev/null
+++ b/js/src/jit-test/tests/parser/bug-975484.js
@@ -0,0 +1,7 @@
+var loc = Reflect.parse("f()").body[0].expression.loc;
+assertEq(loc.start.column, 0);
+assertEq(loc.end.column, 3);
+
+loc = Reflect.parse("f(x)").body[0].expression.loc;
+assertEq(loc.start.column, 0);
+assertEq(loc.end.column, 4);