[CodeCompletion] Parse #if block containing CC token as active

rdar://problem/67027408

Author: rintaro

lib/Parse/ParseIfConfig.cpp

@@ -603,17 +603,33 @@ static Expr *findAnyLikelySimulatorEnvironmentTest(Expr *Condition) {
 /// Delegate callback function to parse elements in the blocks.
 ParserResult<IfConfigDecl> Parser::parseIfConfig(
     llvm::function_ref<void(SmallVectorImpl<ASTNode> &, bool)> parseElements) {
+  assert(Tok.is(tok::pound_if));
   SyntaxParsingContext IfConfigCtx(SyntaxContext, SyntaxKind::IfConfigDecl);
 
   SmallVector<IfConfigClause, 4> Clauses;
   Parser::StructureMarkerRAII ParsingDecl(
       *this, Tok.getLoc(), Parser::StructureMarkerKind::IfConfig);
 
+  // See if this '#if ... #endif' directive contains code completion token.
+  bool hasCCToken = false;
+  if (SourceMgr.hasCodeCompletionBuffer() &&
+      SourceMgr.getCodeCompletionBufferID() == L->getBufferID()) {
+    BacktrackingScope backtrack(*this);
+    auto startLoc = Tok.getLoc();
+    skipSingle();
+    auto endLoc = PreviousLoc;
+    hasCCToken = SourceMgr.rangeContainsTokenLoc(
+        SourceRange(startLoc, endLoc), SourceMgr.getCodeCompletionLoc());
+  }
+
   bool shouldEvaluate =
       // Don't evaluate if it's in '-parse' mode, etc.
       shouldEvaluatePoundIfDecls() &&
       // If it's in inactive #if ... #endif block, there's no point to do it.
-      !getScopeInfo().isInactiveConfigBlock();
+      !getScopeInfo().isInactiveConfigBlock() &&
+      // If this directive contains code completion, 'isActive' is determined
+      // solely by which block has the completion token.
+      !hasCCToken;
 
   bool foundActive = false;
   bool isVersionCondition = false;
@@ -658,6 +674,16 @@ ParserResult<IfConfigDecl> Parser::parseIfConfig(
       }
     }
 
+    // Treat the region containing code completion token as "active".
+    if (hasCCToken && !foundActive) {
+      BacktrackingScope backtrack(*this);
+      auto startLoc = Tok.getLoc();
+      skipUntilConditionalBlockClose();
+      auto endLoc = PreviousLoc;
+      isActive = SourceMgr.rangeContainsTokenLoc(
+          SourceRange(startLoc, endLoc), SourceMgr.getCodeCompletionLoc());
+    }
+
     foundActive |= isActive;
 
     if (!Tok.isAtStartOfLine() && Tok.isNot(tok::eof)) {

lib/Parse/Parser.cpp

@@ -695,8 +695,9 @@ void Parser::skipSingle() {
 void Parser::skipUntil(tok T1, tok T2) {
   // tok::NUM_TOKENS is a sentinel that means "don't skip".
   if (T1 == tok::NUM_TOKENS && T2 == tok::NUM_TOKENS) return;
-  
-  while (Tok.isNot(T1, T2, tok::eof, tok::pound_endif, tok::code_complete))
+
+  while (Tok.isNot(T1, T2, tok::eof, tok::pound_endif, tok::pound_else,
+                   tok::pound_elseif))
     skipSingle();
 }
 

test/IDE/complete_in_ifconfig.swift

@@ -0,0 +1,75 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-ide-test -batch-code-completion -source-filename %s -filecheck %raw-FileCheck -completion-output-dir %t
+
+struct MyStruct {
+    init() {}
+    var value: Int
+}
+
+// MEMBER_MyStruct: Begin completions, 2 items
+// MEMBER_MyStruct-DAG: Keyword[self]/CurrNominal:          self[#MyStruct#];
+// MEMBER_MyStruct-DAG: Decl[InstanceVar]/CurrNominal:      value[#Int#];
+// MEMBER_MyStruct: End completions
+
+#if true
+let toplevelActive = MyStruct()
+_ = toplevelActive.#^MEMBER_TOPLEVEL_ACTIVE?check=MEMBER_MyStruct^#
+#else
+let toplevelInactive = MyStruct()
+_ = toplevelInactive.#^MEMBER_TOPLEVEL_INACTIVE?check=MEMBER_MyStruct^#
+#endif
+
+func foo() {
+#if true
+  let infuncActive = MyStruct()
+  _ = infuncActive.#^MEMBER_INFUNC_ACTIVE?check=MEMBER_MyStruct^#
+#else
+  let infuncInactive = MyStruct()
+  _ = infuncInactive.#^MEMBER_INFUNC_INACTIVE?check=MEMBER_MyStruct^#
+#endif
+}
+
+protocol TestP {
+  func foo()
+  func bar()
+}
+struct TestStruct: TestP {
+#if true
+  func foo() {}
+  func #^OVERRIDE_ACTIVE^#
+// OVERRIDE_ACTIVE: Begin completions, 1 items
+// OVERRIDE_ACTIVE-DAG: Decl[InstanceMethod]/Super:         bar() {|};
+// OVERRIDE_ACTIVE: End completions
+#else
+  func bar() {}
+  func #^OVERRIDE_INACTIVE^#
+// OVERRIDE_INACTIVE: Begin completions, 1 items
+// OVERRIDE_INACTIVE-DAG: Decl[InstanceMethod]/Super:         foo() {|};
+// OVERRIDE_INACTIVE: End completions
+#endif
+}
+
+struct TestStruct2 {
+#if true
+  func activeFunc() {}
+  func test() {
+    self.#^SELF_ACTIVE^#
+  }
+// SELF_ACTIVE: Begin completions, 3 items
+// SELF_ACTIVE-DAG: Keyword[self]/CurrNominal:          self[#TestStruct2#];
+// SELF_ACTIVE-DAG: Decl[InstanceMethod]/CurrNominal:   activeFunc()[#Void#];
+// SELF_ACTIVE-DAG: Decl[InstanceMethod]/CurrNominal:   test()[#Void#];
+// SELF_ACTIVE: End completions
+#else
+  func inactiveFunc() {}
+  func test() {
+    self.#^SELF_INACTIVE^#
+  }
+// SELF_INACTIVE: Begin completions, 3 items
+// SELF_INACTIVE-DAG: Keyword[self]/CurrNominal:          self[#TestStruct2#];
+// SELF_INACTIVE-DAG: Decl[InstanceMethod]/CurrNominal:   inactiveFunc()[#Void#];
+// SELF_INACTIVE-DAG: Decl[InstanceMethod]/CurrNominal:   test()[#Void#];
+// SELF_INACTIVE: End completions
+#endif
+}
+