[Typechecker] Use CallArgs for checking duplicate label & add new test cases

Author: theblixguy

lib/Sema/MiscDiagnostics.cpp

@@ -76,7 +76,6 @@ static void diagSyntacticUseRestrictions(TypeChecker &TC, const Expr *E,
   public:
     TypeChecker &TC;
     const DeclContext *DC;
-    CallExpr *funcCallExpr = nullptr;
 
     DiagnoseWalker(TypeChecker &TC, const DeclContext *DC, bool isExprStmt)
       : IsExprStmt(isExprStmt), TC(TC), DC(DC) {}
@@ -135,10 +134,6 @@ static void diagSyntacticUseRestrictions(TypeChecker &TC, const Expr *E,
         }
       }
 
-      if (auto CE = dyn_cast<CallExpr>(E)) {
-        funcCallExpr = CE;
-      }
-
       // Check function calls, looking through implicit conversions on the
       // function and inspecting the arguments directly.
       if (auto *Call = dyn_cast<ApplyExpr>(E)) {
@@ -255,14 +250,14 @@ static void diagSyntacticUseRestrictions(TypeChecker &TC, const Expr *E,
         // FIXME: Duplicate labels on enum payloads should be diagnosed
         // when declared, not when called.
         bool isEnumCase = false;
-        if (funcCallExpr) {
-          auto calledValue = funcCallExpr->getCalledValue();
+        if (auto CE = dyn_cast_or_null<CallExpr>(Parent.getAsExpr())) {
+          auto calledValue = CE->getCalledValue();
           if (calledValue) {
             isEnumCase = isa<EnumElementDecl>(calledValue);
           }
         }
 
-        if (!funcCallExpr || isEnumCase) {
+        if ((!CallArgs.count(tupleExpr)) || isEnumCase) {
           auto diagnose = false;
 
           llvm::SmallDenseSet<Identifier> names;

test/Constraints/tuple.swift

@@ -307,3 +307,15 @@ if case (foo: let x, foo: let y) = zeroTuple { print(x+y) } // expected-error {{
 
 enum BishBash { case bar(foo: Int, foo: String) }
 let enumLabelDup: BishBash = .bar(foo: 0, foo: "") // expected-error {{cannot create a tuple with a duplicate element label}}
+
+func dupLabelClosure(_ fn: () -> Void) {}
+dupLabelClosure { print((bar: "", bar: 5).bar) } // expected-error {{cannot create a tuple with a duplicate element label}}
+
+struct DupLabelSubscript {
+  subscript(foo x: Int, foo y: Int) -> Int {
+    return 0
+  }
+}
+
+let dupLabelSubscriptStruct = DupLabelSubscript()
+let _ = dupLabelSubscriptStruct[foo: 5, foo: 5] // ok

test/Parse/strange_interpolation.swift

@@ -34,8 +34,8 @@ print("[\(x, foo: x)]")
 // expected-warning@-2{{interpolating multiple values will not form a tuple in Swift 5}}
 // expected-note@-3{{insert parentheses to keep current behavior}} {{11-11=(}} {{20-20=)}}
 
-print("[\(foo: x, foo: x)]")
-// CHECK-NEXT: [(foo: 1, foo: 1)]
+print("[\(foo: x, bar: x)]")
+// CHECK-NEXT: [(foo: 1, bar: 1)]
 // expected-warning@-2{{interpolating multiple values will not form a tuple in Swift 5}}
 // expected-note@-3{{insert parentheses to keep current behavior}} {{11-11=(}} {{25-25=)}}