Merge pull request #29763 from rintaro/ide-unqualifiedlookup-rdar58881999

[CodeCompletion] Workaround fast-completion issue in UnqualifiedLookup

Author: rintaro

include/swift/Basic/SourceManager.h

@@ -76,6 +76,10 @@ class SourceManager {
     CodeCompletionOffset = Offset;
   }
 
+  bool hasCodeCompletionBuffer() const {
+    return CodeCompletionBufferID != 0U;
+  }
+
   unsigned getCodeCompletionBufferID() const {
     return CodeCompletionBufferID;
   }

lib/AST/UnqualifiedLookup.cpp

@@ -58,19 +58,34 @@ namespace {
     // lookup.
     if (loc.isInvalid() || decl->getBraces().isInvalid())
       return true;
-    
+
+    SourceManager &SM = decl->getASTContext().SourceMgr;
+
+    // If a code completion happens inside a function body, some lookups may
+    // happen from the 'loc' that is in a different buffer from the 'decl'.
+    // In such cases, look for members of the 'decl' because we know 'loc' is
+    // inside a function body in the 'decl'.
+    if (SM.hasCodeCompletionBuffer()) {
+      auto completionBufferID = SM.getCodeCompletionBufferID();
+      if (SM.getRangeForBuffer(completionBufferID).contains(loc)) {
+        auto declBufferID =
+            decl->getDeclContext()->getParentSourceFile()->getBufferID();
+        if (completionBufferID != declBufferID)
+          return true;
+      }
+    }
+
     // Within the braces, always look for members.
-    auto &ctx = decl->getASTContext();
     auto braces = decl->getBraces();
     if (braces.Start != braces.End &&
-        ctx.SourceMgr.rangeContainsTokenLoc(braces, loc))
+        SM.rangeContainsTokenLoc(braces, loc))
       return true;
 
     // Within 'where' clause, we can also look for members.
     if (auto *whereClause = decl->getTrailingWhereClause()) {
       SourceRange whereClauseRange = whereClause->getSourceRange();
       if (whereClauseRange.isValid() &&
-          ctx.SourceMgr.rangeContainsTokenLoc(whereClauseRange, loc)) {
+          SM.rangeContainsTokenLoc(whereClauseRange, loc)) {
         return true;
       }
     }

test/SourceKit/CodeComplete/complete_sequence_nestedtype.swift

@@ -0,0 +1,50 @@
+struct Outer {
+  enum Inner {
+    case east, west
+    static func staticMethod() {}
+    func instanceMethod() {}
+
+    func test() {
+      Inner.
+    }
+  }
+
+  func test() {
+    Inner.
+  }
+}
+
+// RUN: %sourcekitd-test \
+// RUN:   -req=track-compiles == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=8:13 %s -- %s == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=8:13 %s -- %s == \
+// RUN:   -req=complete -req-opts=reuseastcontext=1 -pos=13:11 %s -- %s \
+// RUN:   > %t.response
+// RUN: %FileCheck --check-prefix=RESULT  %s < %t.response
+// RUN: %FileCheck --check-prefix=TRACE  %s < %t.response
+
+// RESULT-LABEL: key.results: [
+// RESULT-DAG: key.description: "east"
+// RESULT-DAG: key.description: "west"
+// RESULT-DAG: key.description: "staticMethod()"
+// RESULT-DAG: key.description: "instanceMethod(self: Outer.Inner)"
+// RESULT: ]
+// RESULT-LABEL: key.results: [
+// RESULT-DAG: key.description: "east"
+// RESULT-DAG: key.description: "west"
+// RESULT-DAG: key.description: "staticMethod()"
+// RESULT-DAG: key.description: "instanceMethod(self: Outer.Inner)"
+// RESULT: ]
+// RESULT-LABEL: key.results: [
+// RESULT-DAG: key.description: "east"
+// RESULT-DAG: key.description: "west"
+// RESULT-DAG: key.description: "staticMethod()"
+// RESULT-DAG: key.description: "instanceMethod(self: Inner)"
+// RESULT: ]
+
+// TRACE-LABEL: key.notification: source.notification.compile-did-finish,
+// TRACE-NOT: key.description: "completion reusing previous ASTContext (benign diagnostic)"
+// TRACE-LABEL: key.notification: source.notification.compile-did-finish,
+// TRACE: key.description: "completion reusing previous ASTContext (benign diagnostic)"
+// TRACE-LABEL: key.notification: source.notification.compile-did-finish,
+// TRACE: key.description: "completion reusing previous ASTContext (benign diagnostic)"