[SourceKit] Add accessibility in extension structure (SR-4823) (#11260)

Author: marcelofabri

test/SourceKit/DocumentStructure/Inputs/access.swift

@@ -89,6 +89,12 @@ extension PrivAccess {
 private extension PubAccess {
   func privExtFunc() {}
 }
+internal extension DefAccess {
+  func internalExtFunc() {}
+}
+public extension PubAccess {
+  func publicExtFunc() {}
+}
 
 typealias defAlias = Int
 public typealias pubAlias = Int

test/SourceKit/DocumentStructure/access_parse.swift.response

@@ -1,6 +1,6 @@
 {
   key.offset: 0,
-  key.length: 1758,
+  key.length: 1876,
   key.diagnostic_stage: source.diagnostic.stage.swift.parse,
   key.substructure: [
     {
@@ -630,6 +630,7 @@
     },
     {
       key.kind: source.lang.swift.decl.extension,
+      key.accessibility: source.lang.swift.accessibility.private,
       key.name: "PubAccess",
       key.offset: 1584,
       key.length: 47,
@@ -651,40 +652,88 @@
         }
       ]
     },
+    {
+      key.kind: source.lang.swift.decl.extension,
+      key.accessibility: source.lang.swift.accessibility.internal,
+      key.name: "DefAccess",
+      key.offset: 1641,
+      key.length: 51,
+      key.nameoffset: 1651,
+      key.namelength: 9,
+      key.bodyoffset: 1662,
+      key.bodylength: 29,
+      key.substructure: [
+        {
+          key.kind: source.lang.swift.decl.function.method.instance,
+          key.accessibility: source.lang.swift.accessibility.internal,
+          key.name: "internalExtFunc()",
+          key.offset: 1665,
+          key.length: 25,
+          key.nameoffset: 1670,
+          key.namelength: 17,
+          key.bodyoffset: 1689,
+          key.bodylength: 0
+        }
+      ]
+    },
+    {
+      key.kind: source.lang.swift.decl.extension,
+      key.accessibility: source.lang.swift.accessibility.public,
+      key.name: "PubAccess",
+      key.offset: 1700,
+      key.length: 49,
+      key.nameoffset: 1710,
+      key.namelength: 9,
+      key.bodyoffset: 1721,
+      key.bodylength: 27,
+      key.substructure: [
+        {
+          key.kind: source.lang.swift.decl.function.method.instance,
+          key.accessibility: source.lang.swift.accessibility.public,
+          key.name: "publicExtFunc()",
+          key.offset: 1724,
+          key.length: 23,
+          key.nameoffset: 1729,
+          key.namelength: 15,
+          key.bodyoffset: 1746,
+          key.bodylength: 0
+        }
+      ]
+    },
     {
       key.kind: source.lang.swift.decl.typealias,
       key.accessibility: source.lang.swift.accessibility.internal,
       key.name: "defAlias",
-      key.offset: 1633,
+      key.offset: 1751,
       key.length: 24,
-      key.nameoffset: 1643,
+      key.nameoffset: 1761,
       key.namelength: 8
     },
     {
       key.kind: source.lang.swift.decl.typealias,
       key.accessibility: source.lang.swift.accessibility.public,
       key.name: "pubAlias",
-      key.offset: 1665,
+      key.offset: 1783,
       key.length: 24,
-      key.nameoffset: 1675,
+      key.nameoffset: 1793,
       key.namelength: 8
     },
     {
       key.kind: source.lang.swift.decl.typealias,
       key.accessibility: source.lang.swift.accessibility.private,
       key.name: "privAlias",
-      key.offset: 1698,
+      key.offset: 1816,
       key.length: 25,
-      key.nameoffset: 1708,
+      key.nameoffset: 1826,
       key.namelength: 9
     },
     {
       key.kind: source.lang.swift.decl.typealias,
       key.accessibility: source.lang.swift.accessibility.internal,
       key.name: "intAlias",
-      key.offset: 1733,
+      key.offset: 1851,
       key.length: 24,
-      key.nameoffset: 1743,
+      key.nameoffset: 1861,
       key.namelength: 8
     }
   ]

tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp

@@ -912,13 +912,21 @@ static UIdent getAccessibilityUID(Accessibility Access) {
   llvm_unreachable("Unhandled Accessibility in switch.");
 }
 
-static Accessibility inferDefaultAccessibility(const ExtensionDecl *ED) {
+static Optional<Accessibility> getAccessibilityStrictly(const ExtensionDecl *ED) {
   if (ED->hasDefaultAccessibility())
     return ED->getDefaultAccessibility();
 
+  // Check if the decl has an explicit accessibility attribute.
   if (auto *AA = ED->getAttrs().getAttribute<AccessibilityAttr>())
     return AA->getAccess();
 
+  return None;
+}
+
+static Accessibility inferDefaultAccessibility(const ExtensionDecl *ED) {
+  if (auto StrictAccess = getAccessibilityStrictly(ED))
+    return StrictAccess.getValue();
+
   // Assume "internal", which is the most common thing anyway.
   return Accessibility::Internal;
 }
@@ -1025,6 +1033,9 @@ class SwiftDocumentStructureWalker: public ide::SyntaxModelWalker {
     if (Node.Kind != SyntaxStructureKind::Parameter) {
       if (auto *VD = dyn_cast_or_null<ValueDecl>(Node.Dcl)) {
         AccessLevel = getAccessibilityUID(inferAccessibility(VD));
+      } else if (auto *ED = dyn_cast_or_null<ExtensionDecl>(Node.Dcl)) {
+        if (auto StrictAccess = getAccessibilityStrictly(ED))
+          AccessLevel = getAccessibilityUID(StrictAccess.getValue());
       }
       if (auto *ASD = dyn_cast_or_null<AbstractStorageDecl>(Node.Dcl)) {
         Optional<Accessibility> SetAccess = inferSetterAccessibility(ASD);