Merge pull request swiftlang#34486 from rintaro/ide-completion-rdar69246891

[CodeCompletion] Fix a crash in collectPossibleReturnTypesFromContext

Author: rintaro

lib/Sema/TypeCheckStmt.cpp

@@ -1933,11 +1933,13 @@ bool TypeCheckASTNodeAtLocRequest::evaluate(Evaluator &evaluator,
   // The enclosing closure might be a single expression closure or a function
   // builder closure. In such cases, the body elements are type checked with
   // the closure itself. So we need to try type checking the enclosing closure
-  // signature first.
+  // signature first unless it has already been type checked.
   if (auto CE = dyn_cast<ClosureExpr>(DC)) {
-    swift::typeCheckASTNodeAtLoc(CE->getParent(), CE->getLoc());
-    if (CE->getBodyState() != ClosureExpr::BodyState::ReadyForTypeChecking)
-      return false;
+    if (CE->getBodyState() == ClosureExpr::BodyState::Parsed) {
+      swift::typeCheckASTNodeAtLoc(CE->getParent(), CE->getLoc());
+      if (CE->getBodyState() != ClosureExpr::BodyState::ReadyForTypeChecking)
+        return false;
+    }
   }
 
   TypeChecker::typeCheckASTNode(finder.getRef(), DC,

validation-test/IDE/crashers_2_fixed/rdar69246891.swift

@@ -0,0 +1,12 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=COMPLETE -source-filename=%s
+
+class MyCls {
+  public init(body: (Int) throws -> Void) {}
+}
+
+func foo() {
+  MyCls { arg in
+    MyCls { #^COMPLETE^#
+    }
+  }
+}