[SourceKit] Force print '?' for optional method call in code completion.

Calling '@objc optional func' requires '?' or '!' after its name. When
completing method calls for them, 'key.sourcetext' should have '?'
whereas 'key.name' shouldn't.
Note that we deliberately do not use optional type name for
'key.typename'. This is consistent with optional chain '?.<propertyName>'
behavior.

rdar://problem/37904574

Author: rintaro

lib/IDE/CodeCompletion.cpp

@@ -1232,6 +1232,7 @@ void CodeCompletionString::getName(raw_ostream &OS) const {
       case ChunkKind::TypeAnnotation:
       case ChunkKind::CallParameterClosureType:
       case ChunkKind::DeclAttrParamColon:
+      case ChunkKind::OptionalMethodCallTail:
         continue;
       case ChunkKind::ThrowsKeyword:
       case ChunkKind::RethrowsKeyword:

lib/IDE/CodeCompletionResultBuilder.h

@@ -426,8 +426,7 @@ class CodeCompletionResultBuilder {
 
   void addOptionalMethodCallTail() {
     addChunkWithTextNoCopy(
-        CodeCompletionString::Chunk::ChunkKind::OptionalMethodCallTail, "!");
-    getLastChunk().setIsAnnotation();
+        CodeCompletionString::Chunk::ChunkKind::OptionalMethodCallTail, "?");
   }
 
   void addTypeAnnotation(StringRef Type) {

test/IDE/complete_members_optional.swift

@@ -29,7 +29,7 @@ func optionalMembers1(_ a: HasOptionalMembers1) {
   a.#^OPTIONAL_MEMBERS_1^#
 }
 // OPTIONAL_MEMBERS_1: Begin completions, 3 items
-// OPTIONAL_MEMBERS_1-DAG: Decl[InstanceMethod]/CurrNominal:   optionalInstanceFunc!()[#Int#]{{; name=.+$}}
+// OPTIONAL_MEMBERS_1-DAG: Decl[InstanceMethod]/CurrNominal:   optionalInstanceFunc?()[#Int#]{{; name=.+$}}
 // OPTIONAL_MEMBERS_1-DAG: Decl[InstanceVar]/CurrNominal:      optionalInstanceProperty[#Int?#]{{; name=.+$}}
 // OPTIONAL_MEMBERS_1-DAG: Keyword[self]/CurrNominal: self[#HasOptionalMembers1#]; name=self
 // OPTIONAL_MEMBERS_1: End completions
@@ -38,8 +38,8 @@ func optionalMembers2<T : HasOptionalMembers1>(_ a: T) {
   T.#^OPTIONAL_MEMBERS_2^#
 }
 // OPTIONAL_MEMBERS_2: Begin completions, 4 items
-// OPTIONAL_MEMBERS_2-DAG: Decl[InstanceMethod]/Super:         optionalInstanceFunc!({#self: HasOptionalMembers1#})[#() -> Int#]{{; name=.+$}}
-// OPTIONAL_MEMBERS_2-DAG: Decl[StaticMethod]/Super:           optionalClassFunc!()[#Int#]{{; name=.+$}}
+// OPTIONAL_MEMBERS_2-DAG: Decl[InstanceMethod]/Super:         optionalInstanceFunc?({#self: HasOptionalMembers1#})[#() -> Int#]{{; name=.+$}}
+// OPTIONAL_MEMBERS_2-DAG: Decl[StaticMethod]/Super:           optionalClassFunc?()[#Int#]{{; name=.+$}}
 // OPTIONAL_MEMBERS_2-DAG: Decl[StaticVar]/Super:              optionalClassProperty[#Int?#]{{; name=.+$}}
 // OPTIONAL_MEMBERS_2-DAG: Keyword[self]/CurrNominal: self[#T.Type#]; name=self
 // OPTIONAL_MEMBERS_2: End completions

test/SourceKit/CodeComplete/complete_optionalmethod.swift

@@ -0,0 +1,11 @@
+@objc protocol Proto {
+  @objc optional func optionalMethod() -> Int
+}
+
+func test<T : Proto>(obj: T) {
+  let _ = obj.
+}
+
+// RUN: %sourcekitd-test -req=complete -pos=6:15 %s -- %s > %t.response
+// RUN: diff -u %s.response %t.response
+// REQUIRES: objc_interop

test/SourceKit/CodeComplete/complete_optionalmethod.swift.response

@@ -0,0 +1,24 @@
+{
+  key.results: [
+    {
+      key.kind: source.lang.swift.decl.function.method.instance,
+      key.name: "optionalMethod()",
+      key.sourcetext: "optionalMethod?()",
+      key.description: "optionalMethod?()",
+      key.typename: "Int",
+      key.context: source.codecompletion.context.superclass,
+      key.num_bytes_to_erase: 0,
+      key.associated_usrs: "c:@M@complete_optionalmethod@objc(pl)Proto(im)optionalMethod",
+      key.modulename: "complete_optionalmethod"
+    },
+    {
+      key.kind: source.lang.swift.keyword,
+      key.name: "self",
+      key.sourcetext: "self",
+      key.description: "self",
+      key.typename: "T",
+      key.context: source.codecompletion.context.thisclass,
+      key.num_bytes_to_erase: 0
+    }
+  ]
+}

tools/SourceKit/lib/SwiftLang/CodeCompletionOrganizer.cpp

@@ -1212,6 +1212,7 @@ void CompletionBuilder::getFilterName(CodeCompletionString *str,
       case ChunkKind::Whitespace:
       case ChunkKind::Ellipsis:
       case ChunkKind::Ampersand:
+      case ChunkKind::OptionalMethodCallTail:
         continue;
       case ChunkKind::CallParameterColon:
         // Since we don't add the type, also don't add the space after ':'.