fixup! issue #65913 - Correct wrong insertion point suggestion when using shorthand optional binding by looking for implicitDeclRefExpr that is optional and points to a VarDecl. If we have that, get the name and insert with fixItInsertAfter instead of fixItInsert.

Author: James Brown

lib/Sema/TypeCheckEffects.cpp

@@ -3599,11 +3599,9 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
       if (!anchor->getType()->isOptional())
         return nullptr;
       anchor->forEachChildExpr([&](Expr *expr) -> Expr * {
-        if (auto declRef = dyn_cast<DeclRefExpr>(expr)) {
-          if (declRef && declRef->isImplicit()) {
-            varDecl = dyn_cast<VarDecl>(declRef->getDecl());
-            return nullptr;
-          }
+        if (isa<DeclRefExpr>(expr) && expr->isImplicit()) {
+          varDecl = dyn_cast<VarDecl>(expr->getReferencedDecl().getDecl());
+          return nullptr;
         }
         return expr;
       });
@@ -3615,7 +3613,7 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>
           return diag.downgradeToWarning;
         });
 
-    if (auto varDecl = findShorthandOptionalBinding(anchor)) {
+    if (auto *varDecl = findShorthandOptionalBinding(anchor)) {
       Ctx.Diags.diagnose(anchor->getStartLoc(), diag::async_expr_without_await)
         .warnUntilSwiftVersionIf(downgradeToWarning, 6)
         .fixItInsertAfter(anchor->getStartLoc(),