[ASTPrinter] Fix issue printing Self resolved to a generic type

When printing a type in type through `ASTPrinter::printTransformedTypeWithOptions`, we are removing any contextual types by mapping the type out of context. However, when substituting `Self` (or any other type member) with their concrete type from `CurrentType`, we might re-introduce contextual types.

To fix this, make sure that `CurrentType` is always an interface type that has all contextual types removed.

Fixes rdar://76021569

lib/AST/ASTPrinter.cpp

@@ -535,6 +535,13 @@ class PrintAST : public ASTVisitor<PrintAST> {
   Decl *Current = nullptr;
   Type CurrentType;
 
+  void setCurrentType(Type NewCurrentType) {
+    CurrentType = NewCurrentType;
+    assert(CurrentType.isNull() ||
+           !CurrentType->hasArchetype() &&
+               "CurrentType should be an interface type");
+  }
+
   friend DeclVisitor<PrintAST>;
 
   /// RAII object that increases the indentation level.
@@ -913,8 +920,13 @@ private:
 public:
   PrintAST(ASTPrinter &Printer, const PrintOptions &Options)
       : Printer(Printer), Options(Options) {
-    if (Options.TransformContext)
-      CurrentType = Options.TransformContext->getBaseType();
+    if (Options.TransformContext) {
+      Type CurrentType = Options.TransformContext->getBaseType();
+      if (CurrentType && CurrentType->hasArchetype()) {
+        CurrentType = CurrentType->mapTypeOutOfContext();
+      }
+      setCurrentType(CurrentType);
+    }
   }
 
   using ASTVisitor::visit;
@@ -941,11 +953,11 @@ public:
       if (auto *NTD = dyn_cast<NominalTypeDecl>(D)) {
         auto Subs = CurrentType->getContextSubstitutionMap(
           Options.CurrentModule, NTD->getDeclContext());
-        CurrentType = NTD->getDeclaredInterfaceType().subst(Subs);
+        setCurrentType(NTD->getDeclaredInterfaceType().subst(Subs));
       }
     }
 
-    SWIFT_DEFER { CurrentType = OldType; };
+    SWIFT_DEFER { setCurrentType(OldType); };
 
     if (Synthesize) {
       Printer.setSynthesizedTarget(Options.TransformContext->getDecl());

test/SourceKit/DocSupport/doc_generic_type_with_self_param.swift

@@ -0,0 +1,29 @@
+// RUN: %empty-directory(%t.mod)
+// RUN: %swift -emit-module -o %t.mod/test.swiftmodule %s -parse-as-library -emit-module-doc-path %t.mod/test.swiftdoc
+// RUN: %sourcekitd-test -req=doc-info -module test -- -I %t.mod | %FileCheck %s
+
+public protocol Proto {}
+
+public struct AttributesSlice1<T> : Proto {}
+
+public struct ListFormatStyle<Style, Base: Proto> {
+  public enum Width {
+    case standard
+    case short
+    case narrow
+  }
+}
+
+public extension Proto {
+  // The tricky part about this test case is that when synthesizing this
+  // extension for `AttributesSlice1`, we replace `Self` by
+  // `AttributesSlice1<T>` but `S` remains an generic parameter. We thus
+  // have a type that contains both an archetype (namely `T` as the generic
+  // paramter of `AttributedSlice1<T>`) and an unbound generic paramters.
+  // This used to cause issues when printing the type.
+  func formatted<S>(width: ListFormatStyle<S, Self>.Width) -> String {
+// CHECK: func formatted<S>(width width: ListFormatStyle<S, AttributesSlice1<T>>.Width) -> String
+    fatalError()
+  }
+}
+

test/SourceKit/DocSupport/doc_swift_module.swift.response

@@ -1643,7 +1643,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "Wrapped",
-    key.usr: "s:4cake2S3VA2A2P6RzrlE7Wrappedxmfp",
+    key.usr: "s:4cake2S3V7Wrappedxmfp",
     key.offset: 2041,
     key.length: 7
   },
@@ -2744,7 +2744,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
         key.original_usr: "s:4cake2P6PAAE4null7ElementQzSgvp",
         key.offset: 2031,
         key.length: 34,
-        key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>null</decl.name>: <decl.var.type><ref.generic_type_param usr=\"s:4cake2S3VA2A2P6RzrlE7Wrappedxmfp\">Wrapped</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake2P5P7ElementQa\">Element</ref.associatedtype>?</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
+        key.fully_annotated_decl: "<decl.var.instance><syntaxtype.keyword>var</syntaxtype.keyword> <decl.name>null</decl.name>: <decl.var.type><ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake2P5P7ElementQa\">Element</ref.associatedtype>?</decl.var.type> { <syntaxtype.keyword>get</syntaxtype.keyword> }</decl.var.instance>"
       }
     ]
   },

test/SourceKit/DocSupport/doc_system_module_underscored.swift.response

@@ -897,7 +897,7 @@ protocol Other1 {
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
-    key.usr: "s:16UnderscoredProto1DVAASQRzrlE1Txmfp",
+    key.usr: "s:16UnderscoredProto1DV1Txmfp",
     key.offset: 1472,
     key.length: 1
   },
@@ -945,7 +945,7 @@ protocol Other1 {
   {
     key.kind: source.lang.swift.ref.generic_type_param,
     key.name: "T",
-    key.usr: "s:16UnderscoredProto1DVAASQRzrlE1Txmfp",
+    key.usr: "s:16UnderscoredProto1DV1Txmfp",
     key.offset: 1585,
     key.length: 1
   },
@@ -1570,7 +1570,7 @@ protocol Other1 {
     ],
     key.offset: 1454,
     key.length: 135,
-    key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:16UnderscoredProto1DV\">D</ref.struct> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DVAASQRzrlE1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:16UnderscoredProto6Other1P\">Other1</ref.protocol></decl.generic_type_requirement>, <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DVAASQRzrlE1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol></decl.generic_type_requirement>",
+    key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:16UnderscoredProto1DV\">D</ref.struct> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:16UnderscoredProto6Other1P\">Other1</ref.protocol></decl.generic_type_requirement>, <decl.generic_type_requirement><ref.generic_type_param usr=\"s:16UnderscoredProto1DVAASQRzrlE1Txmfp\">T</ref.generic_type_param> : <ref.protocol usr=\"s:SQ\">Equatable</ref.protocol></decl.generic_type_requirement>",
     key.extends: {
       key.kind: source.lang.swift.ref.struct,
       key.name: "D",
@@ -1584,7 +1584,7 @@ protocol Other1 {
         key.original_usr: "s:16UnderscoredProto05_SomeB0PA2A6Other14ItemRpzrlE04fromcB24ExtensionSplitConditions05takese2IfD0yAF_tF",
         key.offset: 1505,
         key.length: 82,
-        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromSomeProtoExtensionSplitConditions</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesItemIfOther1</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1DVAASQRzrlE1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
+        key.fully_annotated_decl: "<decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>fromSomeProtoExtensionSplitConditions</decl.name>(<decl.var.parameter><decl.var.parameter.argument_label>takesItemIfOther1</decl.var.parameter.argument_label>: <decl.var.parameter.type><ref.generic_type_param usr=\"s:16UnderscoredProto1DV1Txmfp\">T</ref.generic_type_param></decl.var.parameter.type></decl.var.parameter>)</decl.function.method.instance>",
         key.entities: [
           {
             key.kind: source.lang.swift.decl.var.local,