[Sema] Minimum access for protocol requirement members to 'fileprivate'.

It used to be `internal`.

// ModA/File1.swift
private protocol P  {
  func privMethod() // This was implicitly `internal`.
}
public class C {
  public init() {}
  fileprivate func privMethod() {
    print("FOOBAR")
  }
}

// ModA/File2.swift
extension C {
  public func callPrivMethod() {
    // This should be "error: use of unresolved identifier 'foo'",
    // but was not.
    privMethod()
  }
}

// main.swift
// This ends up runtime error 'fatal error: : call of deleted method'
C().callPrivMethod()

Author: rintaro

lib/Sema/TypeCheckDecl.cpp

@@ -1388,7 +1388,8 @@ void TypeChecker::computeAccessibility(ValueDecl *D) {
       validateAccessibility(generic);
       Accessibility access = Accessibility::Internal;
       if (isa<ProtocolDecl>(generic))
-        access = std::max(access, generic->getFormalAccess());
+        access = std::max(Accessibility::FilePrivate,
+                          generic->getFormalAccess());
       D->setAccessibility(access);
       break;
     }

test/IDE/complete_override_access_control.swift

@@ -112,16 +112,16 @@ public class TestPublicABC : ProtocolAPrivate, ProtocolBInternal, ProtocolCPubli
 
 // TEST_INTERNAL_ABC: Begin completions, 15 items
 // TEST_INTERNAL_ABC-DAG: Decl[Constructor]/Super:    init(fromProtocolA: TagPA) {|}{{; name=.+$}}
-// TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: func protoAFunc(x: TagPA) {|}{{; name=.+$}}
-// TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: func protoAFuncOptional(x: TagPA) {|}{{; name=.+$}}
+// TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: fileprivate func protoAFunc(x: TagPA) {|}{{; name=.+$}}
+// TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: fileprivate func protoAFuncOptional(x: TagPA) {|}{{; name=.+$}}
 // TEST_INTERNAL_ABC-DAG: Decl[Constructor]/Super:    init(fromProtocolB: TagPB) {|}{{; name=.+$}}
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: func protoBFunc(x: TagPB) {|}{{; name=.+$}}
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: func protoBFuncOptional(x: TagPB) {|}{{; name=.+$}}
 // TEST_INTERNAL_ABC-DAG: Decl[Constructor]/Super:    init(fromProtocolC: TagPC) {|}{{; name=.+$}}
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: func protoCFunc(x: TagPC) {|}{{; name=.+$}}
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceMethod]/Super: func protoCFuncOptional(x: TagPC) {|}{{; name=.+$}}
-// TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    var protoAVarRW: TagPA
-// TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    var protoAVarRO: TagPA
+// TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    fileprivate var protoAVarRW: TagPA
+// TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    fileprivate var protoAVarRO: TagPA
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    var protoBVarRW: TagPB
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    var protoBVarRO: TagPB
 // TEST_INTERNAL_ABC-DAG: Decl[InstanceVar]/Super:    var protoCVarRW: TagPC
@@ -130,16 +130,16 @@ public class TestPublicABC : ProtocolAPrivate, ProtocolBInternal, ProtocolCPubli
 
 // TEST_PUBLIC_ABC: Begin completions, 15 items
 // TEST_PUBLIC_ABC-DAG: Decl[Constructor]/Super:    init(fromProtocolA: TagPA) {|}{{; name=.+$}}
-// TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: func protoAFunc(x: TagPA) {|}{{; name=.+$}}
-// TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: func protoAFuncOptional(x: TagPA) {|}{{; name=.+$}}
+// TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: fileprivate func protoAFunc(x: TagPA) {|}{{; name=.+$}}
+// TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: fileprivate func protoAFuncOptional(x: TagPA) {|}{{; name=.+$}}
 // TEST_PUBLIC_ABC-DAG: Decl[Constructor]/Super:    init(fromProtocolB: TagPB) {|}{{; name=.+$}}
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: func protoBFunc(x: TagPB) {|}{{; name=.+$}}
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: func protoBFuncOptional(x: TagPB) {|}{{; name=.+$}}
 // TEST_PUBLIC_ABC-DAG: Decl[Constructor]/Super:    init(fromProtocolC: TagPC) {|}{{; name=.+$}}
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: public func protoCFunc(x: TagPC) {|}{{; name=.+$}}
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceMethod]/Super: public func protoCFuncOptional(x: TagPC) {|}{{; name=.+$}}
-// TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    var protoAVarRW: TagPA
-// TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    var protoAVarRO: TagPA
+// TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    fileprivate var protoAVarRW: TagPA
+// TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    fileprivate var protoAVarRO: TagPA
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    var protoBVarRW: TagPB
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    var protoBVarRO: TagPB
 // TEST_PUBLIC_ABC-DAG: Decl[InstanceVar]/Super:    public var protoCVarRW: TagPC

test/attr/accessibility_print.swift

@@ -122,9 +122,9 @@ public enum DC_PublicEnum {
 private protocol EA_PrivateProtocol {
   // CHECK: {{^}} associatedtype Foo
   associatedtype Foo
-  // CHECK: internal var Bar
+  // CHECK: fileprivate var Bar
   var Bar: Int { get }
-  // CHECK: internal func baz()
+  // CHECK: fileprivate func baz()
   func baz()
 } // CHECK: {{^[}]}}