Fix Self being incorrectly removed in declarations or expressions

Sources/FormattingHelpers.swift

@@ -2441,12 +2441,12 @@ extension Formatter {
                                 processDeclaredVariables(at: &i, names: &members)
                             }
                         } else {
-                            let removeSelf = explicitSelf != .insert && !usingDynamicLookup && !inClosureDisallowingImplicitSelf
-                            let onlyLocal = options.swiftVersion < "5"
-
+                            let removeSelf = explicitSelf != .insert && !usingDynamicLookup && (
+                                (staticSelf && classOrStatic) || (!staticSelf && !inClosureDisallowingImplicitSelf)
+                            )
                             processDeclaredVariables(at: &i, names: &localNames,
                                                      removeSelfKeyword: removeSelf ? selfKeyword : nil,
-                                                     onlyLocal: onlyLocal,
+                                                     onlyLocal: options.swiftVersion < "5",
                                                      scopeAllowsImplicitSelfRebinding: scopeAllowsImplicitSelfRebinding)
                         }
                     case .keyword("func"):
@@ -2586,7 +2586,9 @@ extension Formatter {
                         assert(!isTypeRoot)
                         // Guard is included because it's an error to reference guard vars in body
                         var scopedNames = localNames
-                        let removeSelf = explicitSelf != .insert && !inClosureDisallowingImplicitSelf
+                        let removeSelf = explicitSelf != .insert && !usingDynamicLookup && (
+                            (staticSelf && classOrStatic) || (!staticSelf && !inClosureDisallowingImplicitSelf)
+                        )
                         processDeclaredVariables(
                             at: &index, names: &scopedNames,
                             removeSelfKeyword: removeSelf ? selfKeyword : nil,

Tests/RulesTests+Redundancy.swift

@@ -6433,6 +6433,19 @@ class RedundancyTests: RulesTests {
         testFormatting(for: input, rule: FormatRules.redundantStaticSelf)
     }
 
+    func testPreserveStaticSelfInInstanceFunction() {
+        let input = """
+        enum Foo {
+            static var value = 0
+
+            func f() {
+                Self.value = value
+            }
+        }
+        """
+        testFormatting(for: input, rule: FormatRules.redundantStaticSelf)
+    }
+
     func testPreserveStaticSelfForShadowedProperty() {
         let input = """
         enum Foo {
@@ -6448,7 +6461,7 @@ class RedundancyTests: RulesTests {
 
     func testPreserveStaticSelfInGetter() {
         let input = """
-        public enum Foo {
+        enum Foo {
             static let foo: String = "foo"
 
             var sharedFoo: String {
@@ -6481,6 +6494,20 @@ class RedundancyTests: RulesTests {
         testFormatting(for: input, output, rule: FormatRules.redundantStaticSelf)
     }
 
+    func testPreserveStaticSelfInGuardLet() {
+        let input = """
+        class LocationDeeplink: Deeplink {
+            convenience init?(warnRegion: String) {
+                guard let value = Self.location(for: warnRegion) else {
+                    return nil
+                }
+                self.init(location: value)
+            }
+        }
+        """
+        testFormatting(for: input, rule: FormatRules.redundantStaticSelf)
+    }
+
     // MARK: - semicolons
 
     func testSemicolonRemovedAtEndOfLine() {