Fix clash between match_cond variable and local variable

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -3105,7 +3105,7 @@ bool Converter::ConvertSwitchCaseCondition(clang::SwitchCase *stmt) {
   while (auto *sc = clang::dyn_cast<clang::SwitchCase>(cur)) {
     if (auto *case_stmt = clang::dyn_cast<clang::CaseStmt>(sc)) {
       if (!first) {
-        StrCat("|| v == ");
+        StrCat("|| __v == ");
       }
       Convert(case_stmt->getLHS());
     }
@@ -3127,7 +3127,7 @@ void Converter::EmitSwitchArm(clang::CompoundStmt *body, clang::SwitchCase *sc,
   if (is_default) {
     StrCat("_ => {");
   } else {
-    StrCat("v if v == ");
+    StrCat("__v if __v == ");
     ConvertSwitchCaseCondition(sc);
   }
   for (auto *t : GetSwitchCaseBody(body, sc)) {

tests/unit/switch_basic.cpp

@@ -2,6 +2,7 @@
 
 int basic(int x) {
   int r = 0;
+  int v = 0; // this should not clash with the match_cond translated variable
   switch (x) {
   case 0:
     r = 10;