[CodeComplete] Fix issue with completion in string literal as last token in case stmt

The last token in a case stmt can be a string literal token, which can *contain* its interpolation segments. If one of these interpolation segments is the reference point, we'd return false from `isReferencePointInRange` because the string literal token's start location is before the interpolation token. To fix this, adjust the range we are checking to range until the end of the string interpolation token.

Fixes rdar://76330416 [SR-14455]

Author: ahoppen

lib/AST/NameLookup.cpp

@@ -2842,7 +2842,19 @@ void FindLocalVal::visitBraceStmt(BraceStmt *S, bool isTopLevelCode) {
     if (SM.isBeforeInBuffer(Loc, S->getStartLoc()))
       return;
   } else {
-    if (!isReferencePointInRange(S->getSourceRange()))
+    SourceRange CheckRange = S->getSourceRange();
+    if (S->isImplicit()) {
+      // If the brace statement is implicit, it doesn't have an explicit '}'
+      // token. Thus, the last token in the brace stmt could be a string
+      // literal token, which can *contain* its interpolation segments.
+      // If one of these interpolation segments is the reference point, we'd
+      // return false from `isReferencePointInRange` because the string
+      // literal token's start location is before the interpolation token.
+      // To fix this, adjust the range we are checking to range until the end of
+      // the potential string interpolation token.
+      CheckRange.End = Lexer::getLocForEndOfToken(SM, CheckRange.End);
+    }
+    if (!isReferencePointInRange(CheckRange))
       return;
   }
 
@@ -2867,7 +2879,16 @@ void FindLocalVal::visitSwitchStmt(SwitchStmt *S) {
 }
 
 void FindLocalVal::visitCaseStmt(CaseStmt *S) {
-  if (!isReferencePointInRange(S->getSourceRange()))
+  // The last token in a case stmt can be a string literal token, which can
+  // *contain* its interpolation segments. If one of these interpolation
+  // segments is the reference point, we'd return false from
+  // `isReferencePointInRange` because the string literal token's start location
+  // is before the interpolation token. To fix this, adjust the range we are
+  // checking to range until the end of the potential string interpolation
+  // token.
+  SourceRange CheckRange = {S->getStartLoc(),
+                            Lexer::getLocForEndOfToken(SM, S->getEndLoc())};
+  if (!isReferencePointInRange(CheckRange))
     return;
   // Pattern names aren't visible in the patterns themselves,
   // just in the body or in where guards.

test/IDE/complete_sr14455.swift

@@ -0,0 +1,17 @@
+// RUN: %swift-ide-test -code-completion -source-filename %s -code-completion-token=COMPLETE | %FileCheck %s
+
+public enum Endpoint {
+  case movieDetail
+
+
+  func path() -> String {
+    switch self {
+    case .movieDetail:
+      let myInt: Int = 2
+      return "\(#^COMPLETE^#)"
+    }
+  }
+}
+// CHECK: Begin completions
+// CHECK: Decl[LocalVar]/Local/TypeRelation[Convertible]: myInt[#Int#];
+// CHECK: End completions