[MiscDiagnostics] Store a reference to a call node together with its arguments

Author: xedin

lib/Sema/MiscDiagnostics.cpp

@@ -77,7 +77,9 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
     SmallPtrSet<DeclRefExpr*, 4> AlreadyDiagnosedBitCasts;
 
     /// Keep track of the arguments to CallExprs.
-    SmallPtrSet<Expr *, 2> CallArgs;
+    ///  Key -> an argument expression,
+    ///  Value -> a call argument is associated with.
+    llvm::SmallDenseMap<Expr *, Expr *, 2> CallArgs;
 
     bool IsExprStmt;
 
@@ -141,30 +143,30 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC,
         checkUseOfMetaTypeName(Base);
 
       if (auto *OLE = dyn_cast<ObjectLiteralExpr>(E)) {
-        CallArgs.insert(OLE->getArg());
+        CallArgs.insert({OLE->getArg(), E});
       }
 
       if (auto *SE = dyn_cast<SubscriptExpr>(E))
-        CallArgs.insert(SE->getIndex());
+        CallArgs.insert({SE->getIndex(), E});
 
       if (auto *DSE = dyn_cast<DynamicSubscriptExpr>(E))
-        CallArgs.insert(DSE->getIndex());
+        CallArgs.insert({DSE->getIndex(), E});
 
       if (auto *KPE = dyn_cast<KeyPathExpr>(E)) {
         // raise an error if this KeyPath contains an effectful member.
         checkForEffectfulKeyPath(KPE);
 
         for (auto Comp : KPE->getComponents()) {
           if (auto *Arg = Comp.getIndexExpr())
-            CallArgs.insert(Arg);
+            CallArgs.insert({Arg, E});
         }
       }
 
       // Check function calls, looking through implicit conversions on the
       // function and inspecting the arguments directly.
       if (auto *Call = dyn_cast<ApplyExpr>(E)) {
         // Record call arguments.
-        CallArgs.insert(Call->getArg());
+        CallArgs.insert({Call->getArg(), E});
 
         // Warn about surprising implicit optional promotions.
         checkOptionalPromotions(Call);