Revert "[CS] Record fix when encountering decl reference with placeholder type"

This reverts commit 8102e39.

Author: hamishknight

include/swift/Sema/CSFix.h

@@ -362,9 +362,6 @@ enum class FixKind : uint8_t {
   /// resolved.
   SpecifyTypeForPlaceholder,
 
-  /// Ignore an invalid placeholder in a decl's interface type.
-  IgnoreInvalidPlaceholderInDeclRef,
-
   /// Allow Swift -> C pointer conversion in an argument position
   /// of a Swift function.
   AllowSwiftToCPointerConversion,
@@ -3194,30 +3191,6 @@ class SpecifyTypeForPlaceholder final : public ConstraintFix {
   }
 };
 
-class IgnoreInvalidPlaceholderInDeclRef final : public ConstraintFix {
-  IgnoreInvalidPlaceholderInDeclRef(ConstraintSystem &cs,
-                                    ConstraintLocator *locator)
-      : ConstraintFix(cs, FixKind::IgnoreInvalidPlaceholderInDeclRef, locator) {}
-
-public:
-  std::string getName() const override {
-    return "ignore invalid placeholder in decl ref";
-  }
-
-  bool diagnose(const Solution &solution, bool asNote = false) const override;
-
-  bool diagnoseForAmbiguity(CommonFixesArray commonFixes) const override {
-    return diagnose(*commonFixes.front().first);
-  }
-
-  static IgnoreInvalidPlaceholderInDeclRef *create(ConstraintSystem &cs,
-                                                   ConstraintLocator *locator);
-
-  static bool classof(const ConstraintFix *fix) {
-    return fix->getKind() == FixKind::IgnoreInvalidPlaceholderInDeclRef;
-  }
-};
-
 class AllowRefToInvalidDecl final : public ConstraintFix {
   AllowRefToInvalidDecl(ConstraintSystem &cs, ConstraintLocator *locator)
       : ConstraintFix(cs, FixKind::AllowRefToInvalidDecl, locator) {}

lib/Sema/CSFix.cpp

@@ -2264,20 +2264,6 @@ SpecifyTypeForPlaceholder::create(ConstraintSystem &cs,
   return new (cs.getAllocator()) SpecifyTypeForPlaceholder(cs, locator);
 }
 
-IgnoreInvalidPlaceholderInDeclRef *
-IgnoreInvalidPlaceholderInDeclRef::create(ConstraintSystem &cs, ConstraintLocator *locator) {
-  return new (cs.getAllocator()) IgnoreInvalidPlaceholderInDeclRef(cs, locator);
-}
-
-bool
-IgnoreInvalidPlaceholderInDeclRef::diagnose(const Solution &solution,
-                                            bool asNote) const {
-  // These are diagnosed separately. Unfortunately we can't enforce that a
-  // diagnostic has already been emitted since their diagnosis depends on e.g
-  // type-checking a function body for a placeholder result of a function.
-  return true;
-}
-
 bool AllowRefToInvalidDecl::diagnose(const Solution &solution,
                                      bool asNote) const {
   ReferenceToInvalidDeclaration failure(solution, getLocator());

lib/Sema/CSSimplify.cpp

@@ -16099,7 +16099,6 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
   case FixKind::AllowValueExpansionWithoutPackReferences:
   case FixKind::IgnoreInvalidPatternInExpr:
   case FixKind::IgnoreInvalidPlaceholder:
-  case FixKind::IgnoreInvalidPlaceholderInDeclRef:
   case FixKind::IgnoreOutOfPlaceThenStmt:
   case FixKind::IgnoreMissingEachKeyword:
   case FixKind::AllowInlineArrayLiteralCountMismatch:

lib/Sema/TypeOfReference.cpp

@@ -1084,31 +1084,6 @@ static Type replaceParamErrorTypeByPlaceholder(Type type, ValueDecl *value, bool
                            funcType->getExtInfo());
 }
 
-/// We allow placeholder types in interface types in certain cases to allow
-/// better recovery since we can suggest the inferred type as a replacement.
-/// When referencing those decls though we need to make sure we record a fix
-/// since we cannot form a valid solution with them.
-static void
-recordFixIfNeededForPlaceholderInDecl(ConstraintSystem &cs, ValueDecl *D,
-                                      ConstraintLocatorBuilder locator) {
-  auto mayHavePlaceholder = [&]() -> bool {
-    // Parameters with types may have placeholders, since this allows us to
-    // suggest an inferred type from a default argument. Match the logic in
-    // `getUnopenedTypeOfReference` and only query the interface type if we have
-    // one already.
-    if (auto *PD = dyn_cast<ParamDecl>(D))
-      return PD->hasInterfaceType();
-
-    // Therefore decls with parameter lists may also have placeholders.
-    return D->getParameterList();
-  };
-  if (!mayHavePlaceholder() || !D->getInterfaceType()->hasPlaceholder())
-    return;
-
-  auto *loc = cs.getConstraintLocator(locator);
-  cs.recordFix(IgnoreInvalidPlaceholderInDeclRef::create(cs, loc));
-}
-
 std::pair<Type, Type>
 ConstraintSystem::getTypeOfReferencePre(OverloadChoice choice,
                                         DeclContext *useDC,
@@ -1118,8 +1093,6 @@ ConstraintSystem::getTypeOfReferencePre(OverloadChoice choice,
 
   ASSERT(!!preparedOverload == PreparingOverload);
 
-  recordFixIfNeededForPlaceholderInDecl(*this, value, locator);
-
   if (value->getDeclContext()->isTypeContext() && isa<FuncDecl>(value)) {
     // Unqualified lookup can find operator names within nominal types.
     auto func = cast<FuncDecl>(value);
@@ -1877,8 +1850,6 @@ ConstraintSystem::getTypeOfMemberReferencePre(
   auto *value = choice.getDecl();
   auto functionRefInfo = choice.getFunctionRefInfo();
 
-  recordFixIfNeededForPlaceholderInDecl(*this, value, locator);
-
   // Figure out the instance type used for the base.
   auto baseTy = choice.getBaseType();
   Type baseRValueTy = baseTy->getRValueType();