[IDE] Disable a few code completion specific paths for solver-based CursorInfo

The lexer will be responsible for knowing whether we have a code completion token, everything else will also work for other IDE inspection features.

The changes start to really make sense once I rename CodeCompletion -> IDEInspection in a lot of places.

Author: ahoppen

include/swift/Parse/Parser.h

@@ -192,7 +192,7 @@ class Parser {
   }
 
   bool isCodeCompletionFirstPass() const {
-    return L->isCodeCompletion() && !CodeCompletion;
+    return SourceMgr.hasCodeCompletionBuffer() && !CodeCompletion;
   }
 
   bool allowTopLevelCode() const;

lib/Parse/Lexer.cpp

@@ -209,8 +209,13 @@ void Lexer::initialize(unsigned Offset, unsigned EndOffset) {
   // Initialize code completion.
   if (BufferID == SourceMgr.getCodeCompletionBufferID()) {
     const char *Ptr = BufferStart + SourceMgr.getCodeCompletionOffset();
-    if (Ptr >= BufferStart && Ptr <= BufferEnd)
+    // If the pointer points to a null byte, it's the null byte that was
+    // inserted to mark the code completion token. If the IDE inspection offset
+    // points to a normal character, no code completion token should be
+    // inserted.
+    if (Ptr >= BufferStart && Ptr <= BufferEnd && *Ptr == '\0') {
       CodeCompletionPtr = Ptr;
+    }
   }
 
   ArtificialEOF = BufferStart + EndOffset;

lib/Parse/ParseExpr.cpp

@@ -1388,9 +1388,7 @@ Parser::parseExprPostfixSuffix(ParserResult<Expr> Result, bool isExprBasic,
       assert(activeElements.size() == 1 && activeElements[0].is<Expr *>());
       auto expr = activeElements[0].get<Expr *>();
       ParserStatus status(ICD);
-      if (SourceMgr.getCodeCompletionLoc().isValid() &&
-          SourceMgr.rangeContainsTokenLoc(expr->getSourceRange(),
-                                          SourceMgr.getCodeCompletionLoc()))
+      if (SourceMgr.rangeContainsCodeCompletionLoc(expr->getSourceRange()) && L->isCodeCompletion())
         status.setHasCodeCompletion();
       hasBindOptional |= exprsWithBindOptional.contains(expr);
       Result = makeParserResult(status, expr);
@@ -2818,9 +2816,12 @@ ParserResult<Expr> Parser::parseExprClosure() {
     // Ignore 'CodeCompletionDelayedDeclState' inside closures.
     // Completions inside functions body inside closures at top level should
     // be considered top-level completions.
-    if (State->hasCodeCompletionDelayedDeclState())
+    if (State->hasCodeCompletionDelayedDeclState()) {
       (void)State->takeCodeCompletionDelayedDeclState();
-    Status.setHasCodeCompletionAndIsError();
+    }
+    if (L->isCodeCompletion()) {
+      Status.setHasCodeCompletionAndIsError();
+    }
   }
 
   // Parse the closing '}'.

lib/Parse/ParsePattern.cpp

@@ -1029,7 +1029,7 @@ ParserResult<Pattern> Parser::parseTypedPattern() {
       // as typed patterns, such as "var x: [Int]()".
       // Disable this tentative parse when in code-completion mode, otherwise
       // code-completion may enter the delayed-decl state twice.
-      if (Tok.isFollowingLParen() && !L->isCodeCompletion()) {
+      if (Tok.isFollowingLParen() && !SourceMgr.hasCodeCompletionBuffer()) {
         CancellableBacktrackingScope backtrack(*this);
 
         // Create a local context if needed so we can parse trailing closures.

lib/Sema/CSSimplify.cpp

@@ -5297,7 +5297,7 @@ bool ConstraintSystem::repairFailures(
         // other (explicit) argument's so source range containment alone isn't
         // sufficient.
         bool isSynthesizedArg = arg->isImplicit() && isa<DeclRefExpr>(arg);
-        if (!isSynthesizedArg && containsCodeCompletionLoc(arg) &&
+        if (!isSynthesizedArg && isForCodeCompletion() && containsCodeCompletionLoc(arg) &&
             !lhs->isVoid() && !lhs->isUninhabited())
           return true;
       }

test/SourceKit/CursorInfo/cursor_in_top_level_closure.swift

@@ -0,0 +1,24 @@
+// RUN: %empty-directory(%t/split)
+// RUN: %{python} %utils/split_file.py -o %t/split %s
+// RUN: %empty-directory(%t/build)
+// RUN: %sourcekitd-test -req=cursor -pos=5:9 %t/split/MovieRow.swift -- %t/split/MovieRow.swift %t/split/Color.swift | %FileCheck %s
+
+// BEGIN Color.swift
+
+extension Invalid {}
+
+// BEGIN MovieRow.swift
+
+struct Bar {}
+
+fileprivate let bar: Bar = {
+    let bar = Bar()
+    return bar
+}()
+
+
+// CHECK: source.lang.swift.decl.var.local (5:9-5:12)
+// CHECK-NEXT: bar
+// CHECK: RELATED BEGIN
+// CHECK-NEXT: <RelatedName usr="s:4main3bar33_F48676AE0C86F007C79C860E40EDA2D3LLAA3BarVvp">bar</RelatedName>
+// CHECK-NEXT: RELATED END