[ASTPrinter] Don't print inferred opaque result type witness

Opaque result type syntax is not usable except the declaration of
itself. In other places, users need to let them inferred. If they are
inferred associated type, they need to reffered by the name of the
associated type.

rdar://problem/59817674

Author: rintaro

lib/AST/Type.cpp

@@ -3521,24 +3521,28 @@ static Type getMemberForBaseType(LookupConformanceFn lookupConformances,
 
     // Retrieve the type witness.
     auto witness =
-        conformance.getConcrete()->getTypeWitness(assocType, options);
-    if (!witness || witness->hasError())
+        conformance.getConcrete()->getTypeWitnessAndDecl(assocType, options);
+
+    auto witnessTy = witness.getWitnessType();
+    if (!witnessTy || witnessTy->hasError())
       return failed();
 
     // This is a hacky feature allowing code completion to migrate to
     // using Type::subst() without changing output.
     if (options & SubstFlags::DesugarMemberTypes) {
-      if (auto *aliasType =
-                   dyn_cast<TypeAliasType>(witness.getPointer())) {
-        if (!aliasType->is<ErrorType>())
-          witness = aliasType->getSinglyDesugaredType();
-      }
+      if (auto *aliasType = dyn_cast<TypeAliasType>(witnessTy.getPointer()))
+        witnessTy = aliasType->getSinglyDesugaredType();
+
+      // Another hack. If the type witness is a opaque result type. They can
+      // only be referred using the name of the associated type.
+      if (witnessTy->is<OpaqueTypeArchetypeType>())
+        witnessTy = witness.getWitnessDecl()->getDeclaredInterfaceType();
     }
 
-    if (witness->is<ErrorType>())
+    if (witnessTy->is<ErrorType>())
       return failed();
 
-    return witness;
+    return witnessTy;
   }
 
   return failed();

test/IDE/complete_opaque_result.swift

@@ -22,6 +22,9 @@
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=POSTFIX_TestProtocol_DOT | %FileCheck %s -check-prefix=POSTFIX_TestProtocol_DOT
 // RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=POSTFIX_TestProtocol_NODOT | %FileCheck %s -check-prefix=POSTFIX_TestProtocol_NODOT
 
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=OVERRIDE_TestProtocol2 | %FileCheck %s -check-prefix=OVERRIDE_TestProtocol2
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=POSTFIX_ConcreteTestProtocol2 | %FileCheck %s -check-prefix=POSTFIX_ConcreteTestProtocol2
+
 protocol MyProtocol {
   associatedtype Mistery
 }
@@ -200,3 +203,36 @@ func postfixExpr() {
 // POSTFIX_TestProtocol_NODOT-DAG: BuiltinOperator/None:                = {#TestProtocol#}[#Void#]; name={{.*$}}
 // POSTFIX_TestProtocol_NODOT-DAG: Keyword[self]/CurrNominal:          .self[#TestProtocol#]; name={{.*$}}
 // POSTFIX_TestProtocol_NODOT-DAG: End completions
+
+protocol TestProtocol2 {
+  associatedtype Assoc: Comparable
+  func foo() -> Assoc
+  func bar() -> Assoc
+  func baz(x: @autoclosure () -> Assoc) -> (Assoc) -> Assoc
+}
+extension TestProtocol2 {
+  func inExt() -> Assoc { fatalError() }
+}
+struct ConcreteTestProtocol2: TestProtocol2 {
+  func foo() -> some Comparable { 1 }
+  #^OVERRIDE_TestProtocol2^#
+// OVERRIDE_TestProtocol2: Begin completions
+// OVERRIDE_TestProtocol2-NOT: foo()
+// OVERRIDE_TestProtocol2-NOT: inExt()
+// OVERRIDE_TestProtocol2-DAG: Decl[InstanceMethod]/Super:         func bar() -> Assoc {|};
+// OVERRIDE_TestProtocol2-DAG: Decl[InstanceMethod]/Super:         func baz(x: @autoclosure () -> Assoc) -> (Assoc) -> Assoc {|};
+// OVERRIDE_TestProtocol2-DAG: Decl[AssociatedType]/Super:         typealias Assoc = {#(Type)#};
+// OVERRIDE_TestProtocol2-NOT: foo()
+// OVERRIDE_TestProtocol2-NOT: inExt()
+// OVERRIDE_TestProtocol2: End completions
+}
+func testUseTestProtocol2(value: ConcreteTestProtocol2) {
+  value.#^POSTFIX_ConcreteTestProtocol2^#
+// POSTFIX_ConcreteTestProtocol2: Begin completions
+// POSTFIX_ConcreteTestProtocol2-DAG: Keyword[self]/CurrNominal:          self[#ConcreteTestProtocol2#];
+// POSTFIX_ConcreteTestProtocol2-DAG: Decl[InstanceMethod]/CurrNominal:   foo()[#Comparable#];
+// POSTFIX_ConcreteTestProtocol2-DAG: Decl[InstanceMethod]/Super:         bar()[#ConcreteTestProtocol2.Assoc#];
+// POSTFIX_ConcreteTestProtocol2-DAG: Decl[InstanceMethod]/Super:         baz({#x: ConcreteTestProtocol2.Assoc#})[#(ConcreteTestProtocol2.Assoc) -> ConcreteTestProtocol2.Assoc#];
+// POSTFIX_ConcreteTestProtocol2-DAG: Decl[InstanceMethod]/Super:         inExt()[#ConcreteTestProtocol2.Assoc#];
+// POSTFIX_ConcreteTestProtocol2: End completions
+}

test/SourceKit/CursorInfo/cursor_opaque_result.swift

@@ -0,0 +1,35 @@
+public protocol P {
+  associatedtype Assoc
+  func foo() -> Assoc
+}
+extension P {
+  func bar() -> Assoc { fatalError() }
+}
+
+public struct MyStruct: P {
+  public func foo() -> some Comparable { 1 }
+}
+func test(value: MyStruct) {
+  value.foo()
+  value.bar()
+}
+
+// RUN: %sourcekitd-test -req=cursor -pos=13:9 %s -- %s -module-name MyModule | %FileCheck --check-prefix=OPAQUE %s
+// RUN: %sourcekitd-test -req=cursor -pos=14:9 %s -- %s -module-name MyModule | %FileCheck --check-prefix=ASSOC %s
+
+// OPAQUE: foo()
+// OPAQUE-NEXT: s:8MyModule0A6StructV3fooQryF
+// OPAQUE-NEXT: (MyStruct) -> () -> some Comparable
+// OPAQUE-NEXT: $sQrycD
+// OPAQUE-NEXT: <Container>$s8MyModule0A6StructVD</Container>
+// OPAQUE-NEXT: <Declaration>public func foo() -&gt; some <Type usr="s:SL">Comparable</Type></Declaration>
+// OPAQUE-NEXT: <decl.function.method.instance><syntaxtype.keyword>public</syntaxtype.keyword> <syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>foo</decl.name>() -&gt; <decl.function.returntype><syntaxtype.keyword>some</syntaxtype.keyword> <ref.protocol usr="s:SL">Comparable</ref.protocol></decl.function.returntype></decl.function.method.instance>
+
+
+// ASSOC: bar()
+// ASSOC-NEXT: s:8MyModule1PPAAE3bar5AssocQzyF
+// ASSOC-NEXT: <Self where Self : P> (Self) -> () -> Self.Assoc
+// ASSOC-NEXT: $s5AssocQzycD
+// ASSOC-NEXT: <Container>$s8MyModule0A6StructVD</Container>
+// ASSOC-NEXT: <Declaration>func bar() -&gt; <Type usr="s:8MyModule0A6StructV5Assoca">Assoc</Type></Declaration>
+// ASSOC-NEXT: <decl.function.method.instance><syntaxtype.keyword>func</syntaxtype.keyword> <decl.name>bar</decl.name>() -&gt; <decl.function.returntype><ref.typealias usr="s:8MyModule0A6StructV5Assoca">Assoc</ref.typealias></decl.function.returntype></decl.function.method.instance>