Operator lookups may be private (non-cascading) dependencies.

This helps reduce the impact when touching a file that, say,
defines a custom ==.

Swift SVN r23718

include/swift/AST/Module.h

@@ -839,11 +839,14 @@ public:
   ///
   /// The file must be name-bound already. If the operator is not found, or if
   /// there is an ambiguity, returns null.
-  InfixOperatorDecl *lookupInfixOperator(Identifier name,
+  ///
+  /// \param isNonPrivate If true, the lookup of this operator may affect
+  /// downstream files.
+  InfixOperatorDecl *lookupInfixOperator(Identifier name, bool isNonPrivate,
                                          SourceLoc diagLoc = {});
-  PrefixOperatorDecl *lookupPrefixOperator(Identifier name,
+  PrefixOperatorDecl *lookupPrefixOperator(Identifier name, bool isNonPrivate,
                                            SourceLoc diagLoc = {});
-  PostfixOperatorDecl *lookupPostfixOperator(Identifier name,
+  PostfixOperatorDecl *lookupPostfixOperator(Identifier name, bool isNonPrivate,
                                              SourceLoc diagLoc = {});
   /// @}
 

lib/AST/Module.cpp

@@ -1131,16 +1131,16 @@ Module::lookup##Kind##Operator(Identifier name, SourceLoc loc) { \
   return result ? *result : nullptr; \
 } \
 Kind##OperatorDecl * \
-SourceFile::lookup##Kind##Operator(Identifier name, SourceLoc loc) { \
+SourceFile::lookup##Kind##Operator(Identifier name, bool isNonPrivate, \
+                                   SourceLoc loc) { \
   auto result = lookupOperatorDeclForName(*this, loc, name, true, \
                                           &SourceFile::Kind##Operators); \
-  /* FIXME: Track whether this is a private use or not. */ \
   if (!result.hasValue()) \
     return nullptr; \
   if (ReferencedNames) {\
     if (!result.getValue() || \
         result.getValue()->getDeclContext()->getModuleScopeContext() != this) {\
-      ReferencedNames->addTopLevelName(name, true); \
+      ReferencedNames->addTopLevelName(name, isNonPrivate); \
     } \
   } \
   if (!result.getValue()) { \

lib/Sema/TypeCheckDecl.cpp

@@ -4913,12 +4913,22 @@ public:
     SourceFile &SF = *FD->getDeclContext()->getParentSourceFile();
     if (FD->isUnaryOperator()) {
       if (FD->getAttrs().hasAttribute<PrefixAttr>()) {
-        op = SF.lookupPrefixOperator(operatorName, FD->getLoc());
+        op = SF.lookupPrefixOperator(operatorName,
+                                     !FD->isPrivateContextForLookup(false),
+                                     FD->getLoc());
       } else if (FD->getAttrs().hasAttribute<PostfixAttr>()) {
-        op = SF.lookupPostfixOperator(operatorName,FD->getLoc());
+        op = SF.lookupPostfixOperator(operatorName,
+                                      !FD->isPrivateContextForLookup(false),
+                                      FD->getLoc());
       } else {
-        auto prefixOp = SF.lookupPrefixOperator(operatorName, FD->getLoc());
-        auto postfixOp = SF.lookupPostfixOperator(operatorName, FD->getLoc());
+        auto prefixOp =
+            SF.lookupPrefixOperator(operatorName,
+                                    !FD->isPrivateContextForLookup(false),
+                                    FD->getLoc());
+        auto postfixOp =
+            SF.lookupPostfixOperator(operatorName,
+                                     !FD->isPrivateContextForLookup(false),
+                                     FD->getLoc());
 
         // If we found both prefix and postfix, or neither prefix nor postfix,
         // complain. We can't fix this situation.
@@ -4967,7 +4977,9 @@ public:
                     static_cast<bool>(postfixOp));
       }
     } else if (FD->isBinaryOperator()) {
-      op = SF.lookupInfixOperator(operatorName, FD->getLoc());
+      op = SF.lookupInfixOperator(operatorName,
+                                  !FD->isPrivateContextForLookup(false),
+                                  FD->getLoc());
     } else {
       TC.diagnose(FD, diag::invalid_arg_count_for_operator);
       return;

lib/Sema/TypeCheckExpr.cpp

@@ -130,13 +130,17 @@ static InfixData getInfixData(TypeChecker &TC, DeclContext *DC, Expr *E) {
   } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
     SourceFile *SF = DC->getParentSourceFile();
     Identifier name = DRE->getDecl()->getName();
-    if (InfixOperatorDecl *op = SF->lookupInfixOperator(name, E->getLoc()))
+    bool isPrivate = DC->isPrivateContextForLookup(true);
+    if (InfixOperatorDecl *op = SF->lookupInfixOperator(name, !isPrivate,
+                                                        E->getLoc()))
       return op->getInfixData();
 
   } else if (OverloadedDeclRefExpr *OO = dyn_cast<OverloadedDeclRefExpr>(E)) {
     SourceFile *SF = DC->getParentSourceFile();
     Identifier name = OO->getDecls()[0]->getName();
-    if (InfixOperatorDecl *op = SF->lookupInfixOperator(name, E->getLoc()))
+    bool isPrivate = DC->isPrivateContextForLookup(true);
+    if (InfixOperatorDecl *op = SF->lookupInfixOperator(name, !isPrivate,
+                                                        E->getLoc()))
       return op->getInfixData();
   }
   

test/NameBinding/reference-dependencies.swift

@@ -103,7 +103,7 @@ func lookUpManyTopLevelNames() {
   // CHECK-DAG: !private "+"
   let _: UInt = reduce([1,2], 0, +)
   
-  // CHECK-DAG: - "-"
+  // CHECK-DAG: !private "-"
   let _: UInt = 3 - 2 - 1
 
   // CHECK-DAG: !private "AliasFromOtherFile"