[CodeCompletion] 'case' keyword completion at the top of 'switch' stmt

rdar://problem/35943849
(cherry picked from commit fd542e2)

Author: rintaro

include/swift/IDE/CodeCompletion.h

@@ -492,6 +492,7 @@ enum class CompletionKind {
   TypeSimpleBeginning,
   TypeIdentifierWithDot,
   TypeIdentifierWithoutDot,
+  CaseStmtKeyword,
   CaseStmtBeginning,
   CaseStmtDotPrefix,
   NominalMemberBeginning,

include/swift/Parse/CodeCompletionCallbacks.h

@@ -165,6 +165,9 @@ class CodeCompletionCallbacks {
   /// Complete a given type-identifier when there is no trailing dot.
   virtual void completeTypeIdentifierWithoutDot(IdentTypeRepr *ITR) {};
 
+  /// Complete the beginning of a case statement at the top of switch stmt.
+  virtual void completeCaseStmtKeyword() {};
+
   /// Complete at the beginning of a case stmt pattern.
   virtual void completeCaseStmtBeginning() {};
 

lib/IDE/CodeCompletion.cpp

@@ -1348,6 +1348,7 @@ class CodeCompletionCallbacksImpl : public CodeCompletionCallbacks {
   void completeTypeIdentifierWithDot(IdentTypeRepr *ITR) override;
   void completeTypeIdentifierWithoutDot(IdentTypeRepr *ITR) override;
 
+  void completeCaseStmtKeyword() override;
   void completeCaseStmtBeginning() override;
   void completeCaseStmtDotPrefix() override;
   void completeDeclAttrKeyword(Decl *D, bool Sil, bool Param) override;
@@ -4442,6 +4443,11 @@ void CodeCompletionCallbacksImpl::completeTypeIdentifierWithoutDot(
   CurDeclContext = P.CurDeclContext;
 }
 
+void CodeCompletionCallbacksImpl::completeCaseStmtKeyword() {
+  Kind = CompletionKind::CaseStmtKeyword;
+  CurDeclContext = P.CurDeclContext;
+}
+
 void CodeCompletionCallbacksImpl::completeCaseStmtBeginning() {
   assert(!InEnumElementRawValue);
 
@@ -4623,6 +4629,11 @@ static void addStmtKeywords(CodeCompletionResultSink &Sink, bool MaybeFuncBody)
 #include "swift/Syntax/TokenKinds.def"
 }
 
+static void addCaseStmtKeywords(CodeCompletionResultSink &Sink) {
+  addKeyword(Sink, "case", CodeCompletionKeywordKind::kw_case);
+  addKeyword(Sink, "default", CodeCompletionKeywordKind::kw_default);
+}
+
 static void addLetVarKeywords(CodeCompletionResultSink &Sink) {
   addKeyword(Sink, "let", CodeCompletionKeywordKind::kw_let);
   addKeyword(Sink, "var", CodeCompletionKeywordKind::kw_var);
@@ -4712,6 +4723,10 @@ void CodeCompletionCallbacksImpl::addKeywords(CodeCompletionResultSink &Sink,
     addAnyTypeKeyword(Sink);
     break;
 
+  case CompletionKind::CaseStmtKeyword:
+    addCaseStmtKeywords(Sink);
+    break;
+
   case CompletionKind::PostfixExpr:
   case CompletionKind::PostfixExprParen:
   case CompletionKind::SuperExpr:
@@ -5214,12 +5229,13 @@ void CodeCompletionCallbacksImpl::doneParsing() {
       }
     }
     break;
-  case CompletionKind::AfterIfStmtElse:
-    // Handled earlier by keyword completions.
-    break;
   case CompletionKind::PrecedenceGroup:
     Lookup.getPrecedenceGroupCompletions(SyntxKind);
     break;
+  case CompletionKind::AfterIfStmtElse:
+  case CompletionKind::CaseStmtKeyword:
+    // Handled earlier by keyword completions.
+    break;
   }
 
   for (auto &Request: Lookup.RequestedCachedResults) {

lib/Parse/ParseStmt.cpp

@@ -2273,6 +2273,11 @@ Parser::parseStmtCases(SmallVectorImpl<ASTNode> &cases, bool IsActive) {
       if (auto PDD = PoundDiagnosticResult.getPtrOrNull()) {
         cases.emplace_back(PDD);
       }
+    } else if (Tok.is(tok::code_complete)) {
+      if (CodeCompletion)
+        CodeCompletion->completeCaseStmtKeyword();
+      consumeToken(tok::code_complete);
+      return makeParserCodeCompletionStatus();
     } else {
       // If there are non-case-label statements at the start of the switch body,
       // raise an error and recover by discarding them.

test/IDE/complete_keywords.swift

@@ -90,6 +90,9 @@
 // RUN: %FileCheck %s -check-prefix=KW_EXPR < %t.expr6
 // RUN: %FileCheck %s -check-prefix=KW_EXPR_NEG < %t.expr6
 
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=SWITCH_TOP | %FileCheck %s -check-prefix=KW_CASE
+// RUN: %target-swift-ide-test -code-completion -source-filename %s -code-completion-token=SWITCH_IN_CASE | %FileCheck %s -check-prefix=KW_CASE
+
 // KW_RETURN: Keyword[return]/None: return{{; name=.+$}}
 // KW_NO_RETURN-NOT: Keyword[return]
 
@@ -401,3 +404,16 @@ func inExpr5() {
 func inExpr6() -> Int {
   return #^EXPR_6^#
 }
+
+func inSwitch(val: Int) {
+  switch val {
+  #^SWITCH_TOP^#
+  case 1:
+    foo()
+  #^SWITCH_IN_CASE^#
+  }
+// Begin completions
+// KW_CASE-DAG: Keyword[case]/None:                 case; name=case
+// KW_CASE-DAG: Keyword[default]/None:              default; name=default
+// End completions
+}