[Sema][SR-14408] Increase the impact of missing member fix when member is on argument position

Author: LucianoPAlmeida

lib/Sema/CSSimplify.cpp

@@ -8251,6 +8251,13 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyMemberConstraint(
       if (instanceTy->isAny() || instanceTy->isAnyObject())
         impact += 5;
 
+      // Increasing the impact for missing member in any argument position so it
+      // doesn't affect situations where there are another fixes involved.
+      auto *anchorExpr = getAsExpr(locator->getAnchor());
+      if (anchorExpr && isArgumentExpr(anchorExpr)) {
+        impact += 5;
+      }
+
       if (recordFix(fix, impact))
         return SolutionKind::Error;
 
@@ -8301,7 +8308,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyMemberConstraint(
                               functionRefKind, locator,
                               /*includeInaccessibleMembers*/ true);
 
-      // If uwrapped type still couldn't find anything for a given name,
+      // If unwrapped type still couldn't find anything for a given name,
       // let's fallback to a "not such member" fix.
       if (result.ViableCandidates.empty() && result.UnviableCandidates.empty())
         return fixMissingMember(origBaseTy, memberTy, locator);

lib/Sema/ConstraintSystem.cpp

@@ -4934,6 +4934,15 @@ ConstraintSystem::isArgumentExpr(Expr *expr) {
     return None;
   }
 
+  // Specifically for unresolved member expr getParentExpr returns a chain
+  // result expr as its immediate parent, so let's look one level up on AST.
+  if (auto *URMCR = getAsExpr<UnresolvedMemberChainResultExpr>(argList)) {
+    argList = getParentExpr(URMCR);
+    if (!argList) {
+      return None;
+    }
+  }
+
   if (isa<ParenExpr>(argList)) {
     for (;;) {
       auto *parent = getParentExpr(argList);