[Compiler] add 'value' label for NSNumber to prevent roundabout error message.

Author: JiarenWang

lib/Sema/CSDiagnostics.cpp

@@ -1182,8 +1182,8 @@ bool MissingExplicitConversionFailure::diagnoseAsError() {
     }
   }
 
-  bool needsParensInside = exprNeedsParensBeforeAddingAs(anchor);
-  bool needsParensOutside = exprNeedsParensAfterAddingAs(anchor);
+  bool needsParensInside = exprNeedsParensBeforeAddingAs(anchor, DC);
+  bool needsParensOutside = exprNeedsParensAfterAddingAs(anchor, DC);
 
   llvm::SmallString<2> insertBefore;
   llvm::SmallString<32> insertAfter;
@@ -2940,6 +2940,30 @@ bool ContextualFailure::tryIntegerCastFixIts(
     }
   }
 
+  // bridge to prevent roundabout error message
+  // See rdar://problem/82828226
+  if (TypeChecker::isObjCBridgedTo(fromType, toType, getDC())) {
+    auto *ac = castToExpr(getAnchor());
+    bool needsParensInside = exprNeedsParensBeforeAddingAs(ac, getDC());
+    bool needsParensOutside = exprNeedsParensAfterAddingAs(ac, getDC());
+    llvm::SmallString<2> insertBefore;
+    llvm::SmallString<32> insertAfter;
+    if (needsParensOutside) {
+      insertBefore += "(";
+    }
+    if (needsParensInside) {
+      insertBefore += "(";
+      insertAfter += ")";
+    }
+    insertAfter += " as ";
+    insertAfter += toType->getWithoutParens()->getString();
+    if (needsParensOutside)
+      insertAfter += ")";
+    diagnostic.fixItInsert(exprRange.Start, insertBefore);
+    diagnostic.fixItInsertAfter(exprRange.End, insertAfter);
+    return true;
+  }
+
   // Add a wrapping integer cast.
   std::string convWrapBefore = toType.getString();
   convWrapBefore += "(";

lib/Sema/CSDiagnostics.h

@@ -701,6 +701,29 @@ class ContextualFailure : public FailureDiagnostic {
 
   static Optional<Diag<Type, Type>>
   getDiagnosticFor(ContextualTypePurpose context, Type contextualType);
+
+protected:
+  bool exprNeedsParensBeforeAddingAs(const Expr *expr, DeclContext *DC) const {
+    auto asPG = TypeChecker::lookupPrecedenceGroup(
+                    DC, DC->getASTContext().Id_CastingPrecedence, SourceLoc())
+                    .getSingle();
+    if (!asPG)
+      return true;
+    return exprNeedsParensInsideFollowingOperator(DC, const_cast<Expr *>(expr),
+                                                  asPG);
+  }
+
+  bool exprNeedsParensAfterAddingAs(const Expr *expr, DeclContext *DC) const {
+    auto asPG = TypeChecker::lookupPrecedenceGroup(
+                    DC, DC->getASTContext().Id_CastingPrecedence, SourceLoc())
+                    .getSingle();
+    if (!asPG)
+      return true;
+
+    return exprNeedsParensOutsideFollowingOperator(
+        DC, const_cast<Expr *>(expr), asPG,
+        [&](auto *E) { return findParentExpr(E); });
+  }
 };
 
 /// Diagnose errors related to using an array literal where a
@@ -891,29 +914,6 @@ class MissingExplicitConversionFailure final : public ContextualFailure {
   ASTNode getAnchor() const override;
 
   bool diagnoseAsError() override;
-
-private:
-  bool exprNeedsParensBeforeAddingAs(const Expr *expr) {
-    auto *DC = getDC();
-    auto asPG = TypeChecker::lookupPrecedenceGroup(
-        DC, DC->getASTContext().Id_CastingPrecedence, SourceLoc()).getSingle();
-    if (!asPG)
-      return true;
-    return exprNeedsParensInsideFollowingOperator(DC, const_cast<Expr *>(expr),
-                                                  asPG);
-  }
-
-  bool exprNeedsParensAfterAddingAs(const Expr *expr) {
-    auto *DC = getDC();
-    auto asPG = TypeChecker::lookupPrecedenceGroup(
-        DC, DC->getASTContext().Id_CastingPrecedence, SourceLoc()).getSingle();
-    if (!asPG)
-      return true;
-
-    return exprNeedsParensOutsideFollowingOperator(
-        DC, const_cast<Expr *>(expr), asPG,
-        [&](auto *E) { return findParentExpr(E); });
-  }
 };
 
 /// Diagnose failures related to passing value of some type

test/Constraints/rdar82828226.swift

@@ -0,0 +1,9 @@
+// RUN: %target-typecheck-verify-swift
+
+// REQUIRES: objc_interop
+
+import Foundation
+
+let int: Int = 0
+func a(_ a: NSNumber) {}
+a(int)// expected-error {{cannot convert value of type 'Int' to expected argument type 'NSNumber'}} {{6-6= as NSNumber}}