[CodeCompletion] Stop suggesting initializer calls on unresolved member

For example, for

  class C {
    class D: C {
        init() {}
    }
  }
  let _: C = .#^HERE^#

We used to suggest 'D()' (not just 'D') because it was invalid without
initialization. However, after SE-0287, it can be valid. For example, if
'D' has:

  extension C.D {
    static var staticC: C { ... }
  }

Users can write:

  let _: C = .D.staticC

So we should not suggest constructor calls. Also, this is consistent with
normal type name completion. Users still can get initializer completions
by adding '(' after the type name.

Although initialization call completion with type names was convenient
in some cases, it's too annoying when we have unrelated member types
like:

  enum MyEnum {
    typealias Content = Int
    case value(Content)
  }

We don't want `.Content(bitPattern)` etc for implicit member completion
for 'MyEnum' context type.

rdar://75963052

Author: rintaro

lib/IDE/CodeCompletion.cpp

@@ -3255,7 +3255,7 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
   void addConstructorCallsForType(Type type, Identifier name,
                                   DeclVisibilityKind Reason,
                                   DynamicLookupInfo dynamicLookupInfo) {
-    if (!Ctx.LangOpts.CodeCompleteInitsInPostfixExpr && !IsUnresolvedMember)
+    if (!Ctx.LangOpts.CodeCompleteInitsInPostfixExpr)
       return;
 
     assert(CurrDeclContext);
@@ -3267,10 +3267,6 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
       auto *init = cast<ConstructorDecl>(entry.getValueDecl());
       if (init->shouldHideFromEditor())
         continue;
-      if (IsUnresolvedMember && init->isFailable() &&
-          !init->isImplicitlyUnwrappedOptional()) {
-        continue;
-      }
       addConstructorCall(cast<ConstructorDecl>(init), Reason,
                          dynamicLookupInfo, type, None,
                          /*IsOnType=*/true, name);
@@ -3341,8 +3337,6 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
 
   void addNominalTypeRef(const NominalTypeDecl *NTD, DeclVisibilityKind Reason,
                          DynamicLookupInfo dynamicLookupInfo) {
-    if (IsUnresolvedMember)
-      return;
     CommandWordsPairs Pairs;
     CodeCompletionResultBuilder Builder(
         Sink, CodeCompletionResult::ResultKind::Declaration,
@@ -3371,8 +3365,6 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
 
   void addTypeAliasRef(const TypeAliasDecl *TAD, DeclVisibilityKind Reason,
                        DynamicLookupInfo dynamicLookupInfo) {
-    if (IsUnresolvedMember)
-      return;
     CommandWordsPairs Pairs;
     CodeCompletionResultBuilder Builder(
         Sink, CodeCompletionResult::ResultKind::Declaration,

test/IDE/complete_enum_elements.swift

@@ -127,19 +127,12 @@ enum FooEnum: CaseIterable {
 // FOO_ENUM_DOT_CONTEXT-NEXT: Decl[StaticVar]/CurrNominal: allCases[#[FooEnum]#]{{; name=.+$}}
 // FOO_ENUM_DOT_CONTEXT-NEXT: End completions
 
-// FOO_ENUM_DOT_ELEMENTS: Begin completions, 13 items
+// FOO_ENUM_DOT_ELEMENTS: Begin completions, 6 items
 // FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[EnumElement]/ExprSpecific/TypeRelation[Identical]: Foo1[#FooEnum#]{{; name=.+$}}
 // FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[EnumElement]/ExprSpecific/TypeRelation[Identical]: Foo2[#FooEnum#]{{; name=.+$}}
 // FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[StaticVar]/ExprSpecific/TypeRelation[Identical]: alias1[#FooEnum#]; name=alias1
 // FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[InstanceMethod]/CurrNominal/TypeRelation[Invalid]: hash({#(self): FooEnum#})[#(into: inout Hasher) -> Void#]; name=hash(self: FooEnum)
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#arrayLiteral: FooEnum...#})[#Array<FooEnum>#]; name=AllCases(arrayLiteral: FooEnum...)
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases()[#Array<FooEnum>#]; name=AllCases()
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#(s): Sequence#})[#Array<FooEnum>#]; name=AllCases(s: Sequence)
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#repeating: FooEnum#}, {#count: Int#})[#Array<FooEnum>#]; name=AllCases(repeating: FooEnum, count: Int)
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#unsafeUninitializedCapacity: Int#}, {#initializingWith: (inout UnsafeMutableBufferPointer<FooEnum>, inout Int) throws -> Void##(inout UnsafeMutableBufferPointer<FooEnum>, inout Int) throws -> Void#})[' rethrows'][#Array<FooEnum>#]; name=AllCases(unsafeUninitializedCapacity: Int, initializingWith: (inout UnsafeMutableBufferPointer<FooEnum>, inout Int) throws -> Void) rethrows
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#from: Decoder#})[' throws'][#Array<FooEnum>#]; name=AllCases(from: Decoder) throws
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#repeating: FooEnum#}, {#count: Int#})[#FooEnum.AllCases#]; name=AllCases(repeating: FooEnum, count: Int)
-// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[Constructor]/CurrNominal/IsSystem: AllCases({#(elements): Sequence#})[#FooEnum.AllCases#]; name=AllCases(elements: Sequence)
+// FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[TypeAlias]/CurrNominal: AllCases[#[FooEnum]#]; name=AllCases
 // FOO_ENUM_DOT_ELEMENTS-NEXT: Decl[StaticVar]/CurrNominal:        allCases[#[FooEnum]#]; name=allCases
 // FOO_ENUM_DOT_ELEMENTS-NEXT: End completions
 
@@ -456,7 +449,7 @@ func testUnqualified1(x: QuxEnum) {
   // UNRESOLVED_2: Begin completions
   // UNRESOLVED_2-DAG: Decl[EnumElement]/ExprSpecific/TypeRelation[Identical]:     Qux1[#QuxEnum#]; name=Qux1
   // UNRESOLVED_2-DAG: Decl[EnumElement]/ExprSpecific/TypeRelation[Identical]:     Qux2[#QuxEnum#]; name=Qux2
-  // UNRESOLVED_2-DAG: Decl[Constructor]/CurrNominal/IsSystem:                     RawValue({#bitPattern: UInt#})[#Int#]; name=RawValue(bitPattern: UInt)
+  // UNRESOLVED_2-DAG: Decl[TypeAlias]/CurrNominal:                                RawValue[#Int#]; name=RawValue
   // UNRESOLVED_2-DAG: Decl[Constructor]/CurrNominal:                              init({#rawValue: Int#})[#QuxEnum?#]; name=init(rawValue: Int)
   // UNRESOLVED_2-DAG: Decl[InstanceMethod]/Super/IsSystem/TypeRelation[Invalid]:  hash({#(self): QuxEnum#})[#(into: inout Hasher) -> Void#]; name=hash(self: QuxEnum)
   // UNRESOLVED_2: End completions

test/IDE/complete_unresolved_members.swift

@@ -568,7 +568,7 @@ func testSubType() {
 // SUBTYPE_1: Begin completions, 4 items
 // SUBTYPE_1-NOT: Concrete1(
 // SUBTYPE_1-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Identical]: init()[#BaseClass#];
-// SUBTYPE_1-DAG: Decl[Constructor]/CurrNominal/TypeRelation[Convertible]: SubClass()[#BaseClass.SubClass#];
+// SUBTYPE_1-DAG: Decl[Class]/CurrNominal/TypeRelation[Convertible]: SubClass[#BaseClass.SubClass#];
 // SUBTYPE_1-DAG: Decl[StaticVar]/CurrNominal/TypeRelation[Convertible]: subInstance[#BaseClass.SubClass#];
 // SUBTYPE_1-DAG: Decl[Constructor]/CurrNominal:      init({#failable: Void#})[#BaseClass?#];
 // SUBTYPE_1: End completions