[SourceKit] Expand editor placeholder to trailing closures inside a TryExpr

rdar://108391690

tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp

@@ -1658,7 +1658,14 @@ private:
         auto SR = E->getSourceRange();
         if (SR.isValid() && SM.rangeContainsTokenLoc(SR, TargetLoc) &&
             !checkCallExpr(E) && !EnclosingCallAndArg.first) {
-          OuterExpr = E;
+          if (!isa<TryExpr>(E) && !isa<AwaitExpr>(E) &&
+              !isa<PrefixUnaryExpr>(E)) {
+            // We don't want to expand to trailing closures if the call is
+            // nested inside another expression that has closing characters,
+            // like a `)` for a function call. This is not the case for
+            // `try`, `await` and prefix operator applications.
+            OuterExpr = E;
+          }
         }
         return true;
       }