Currently the GWT compiler adds a var declaration for each catch parameter in

a try/catch statement, but this is unneeded according to the spec, and the
Closure compiler will issue errors against it.

Change-Id: I05dd0429ec22315d57069046b0139ecce045919e
Review-Link: https://gwt-review.googlesource.com/#/c/1810/


git-svn-id: http://google-web-toolkit.googlecode.com/svn/trunk@11490 8db76d5a-ed1c-0410-87a9-c151d255dfc7

Author: [email protected]

dev/core/src/com/google/gwt/dev/jjs/impl/GenerateJavaScriptAST.java

@@ -439,6 +439,7 @@ public boolean visit(JTryStatement x, Context ctx) {
         JsParameter jsParam = jsCatch.getParameter();
         names.put(arg.getTarget(), jsParam.getName());
         catchMap.put(catchBlock, jsCatch);
+        catchParamIdentifiers.add(jsParam.getName());
 
         push(jsCatch.getScope());
         accept(catchBlock);
@@ -1146,7 +1147,9 @@ public void endVisit(JMethodBody x, Context ctx) {
       for (int i = 0; i < locals.size(); ++i) {
         JsName name = names.get(x.getLocals().get(i));
         String ident = name.getIdent();
-        if (!alreadySeen.contains(ident)) {
+        if (!alreadySeen.contains(ident)
+            // Catch block params don't need var declarations
+            && !catchParamIdentifiers.contains(name)) {
           alreadySeen.add(ident);
           vars.add(new JsVar(x.getSourceInfo(), name));
         }
@@ -2337,6 +2340,8 @@ public static JavaToJavaScriptMap exec(JProgram program, JsProgram jsProgram,
 
   private final Map<JBlock, JsCatch> catchMap = new IdentityHashMap<JBlock, JsCatch>();
 
+  private final Set<JsName> catchParamIdentifiers = new HashSet<JsName>();
+
   private final Map<JClassType, JsScope> classScopes = new IdentityHashMap<JClassType, JsScope>();
 
   /**