JS: sharpen js/duplicate-parameter-name

Author: esbena

change-notes/1.24/analysis-javascript.md

@@ -21,6 +21,7 @@
 | **Query**                      | **Expected impact**          | **Change**                                                                |
 |--------------------------------|------------------------------|---------------------------------------------------------------------------|
 | Clear-text logging of sensitive information (`js/clear-text-logging`) | More results | More results involving `process.env` and indirect calls to logging methods are recognized. |
+| Duplicate parameter names (`js/duplicate-parameter-name`) | Fewer results | This query now recognizes additional parameters that reasonably can have duplicated names. |
 | Incomplete string escaping or encoding (`js/incomplete-sanitization`) | Fewer false positive results | This query now recognizes additional cases where a single replacement is likely to be intentional. |
 | Unbound event handler receiver (`js/unbound-event-handler-receiver`) | Fewer false positive results | This query now recognizes additional ways event handler receivers can be bound. | 
 

javascript/ql/src/Declarations/UniqueParameterNames.ql

@@ -36,6 +36,9 @@ where
   i < j and
   j = max(int k | parmBinds(f, k, _, name) | k) and
   not isDummy(p) and
+  // ignore functions without bodies or empty bodies
+  f.hasBody() and
+  exists(f.getABodyStmt()) and
   // duplicate parameters in strict mode functions are flagged by the 'Syntax error' rule
   not f.isStrict()
 select p, "This parameter has the same name as $@ of the same function.", q, "another parameter"

javascript/ql/test/query-tests/Declarations/UniqueParameterNames/UniqueParameterNames.expected

@@ -1,3 +1,2 @@
 | tst.js:2:1:2:1 | x | This parameter has the same name as $@ of the same function. | tst.js:4:1:4:6 | \\u0078 | another parameter |
 | tst.js:3:1:3:1 | x | This parameter has the same name as $@ of the same function. | tst.js:4:1:4:6 | \\u0078 | another parameter |
-| tst.js:17:1:17:1 | x | This parameter has the same name as $@ of the same function. | tst.js:18:1:18:1 | x | another parameter |