[clangd] Skip informative qualifier chunks.

[ilya-biryukov]

Summary

Completion results look much nicer without them.
Informative qualifiers are stored for every method from a base class, even when
calling those methods does not require any qualifiers. For example,

struct Foo { int foo(); };
struct Bar : Foo { };
void test() { Bar(). // Completion item label was 'Foo::foo' before,
                     // but inserted text was simply 'foo'.
                     // We now simply show 'foo' in completion item label.

They effectively cluttered the completion list without providing much value.

[rwols]

test/clangd/completion-qualifiers.test

12 ↗

(On Diff #116001)

CHECK-DAG typo?

[ilya-biryukov]

• Fixed CHECK-DAG typo.

test/clangd/completion-qualifiers.test

12 ↗

(On Diff #116001)

Totally! Thanks for spotting this.

[rwols]

LGTM

clang-tools-extra/trunk/clangd/ClangdUnit.cpp

private:
   }
 
   std::vector<CompletionItem> &Items;
   std::shared_ptr<clang::GlobalCodeCompletionAllocator> Allocator;
   CodeCompletionTUInfo CCTUInfo;
 
 }; // CompletionItemsCollector
 
+bool isInformativeQualifierChunk(CodeCompletionString::Chunk const &Chunk) {
+  return Chunk.Kind == CodeCompletionString::CK_Informative &&
+         StringRef(Chunk.Text).endswith("::");
+}
+
 class PlainTextCompletionItemsCollector final
     : public CompletionItemsCollector {
 
 public:
   PlainTextCompletionItemsCollector(const CodeCompleteOptions &CodeCompleteOpts,
                                     std::vector<CompletionItem> &Items)
       : CompletionItemsCollector(CodeCompleteOpts, Items) {}
 
 private:
   void ProcessChunks(const CodeCompletionString &CCS,
                      CompletionItem &Item) const override {
     for (const auto &Chunk : CCS) {
+      // Informative qualifier chunks only clutter completion results, skip
+      // them.
+      if (isInformativeQualifierChunk(Chunk))
+        continue;
+
       switch (Chunk.Kind) {
       case CodeCompletionString::CK_TypedText:
         // There's always exactly one CK_TypedText chunk.
         Item.insertText = Item.filterText = Chunk.Text;
         Item.label += Chunk.Text;
         break;
       case CodeCompletionString::CK_ResultType:
         assert(Item.detail.empty() && "Unexpected extraneous CK_ResultType");
SnippetCompletionItemsCollector(const CodeCompleteOptions &CodeCompleteOpts,
                                   std::vector<CompletionItem> &Items)
       : CompletionItemsCollector(CodeCompleteOpts, Items) {}
 
 private:
   void ProcessChunks(const CodeCompletionString &CCS,
                      CompletionItem &Item) const override {
     unsigned ArgCount = 0;
     for (const auto &Chunk : CCS) {
+      // Informative qualifier chunks only clutter completion results, skip
+      // them.
+      if (isInformativeQualifierChunk(Chunk))
+        continue;
+
       switch (Chunk.Kind) {
       case CodeCompletionString::CK_TypedText:
         // The piece of text that the user is expected to type to match
         // the code-completion string, typically a keyword or the name of
         // a declarator or macro.
         Item.filterText = Chunk.Text;
         // Note intentional fallthrough here.
       case CodeCompletionString::CK_Text:

clang-tools-extra/trunk/test/clangd/completion-qualifiers.test

+# RUN: clangd -run-synchronously < %s | FileCheck %s
+Content-Length: 125
+
+{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{},"trace":"off"}}
+Content-Length: 297
+
+{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file:///main.cpp","languageId":"cpp","version":1,"text":"class Foo {\n  public:\n    int foo() const;\n    int bar() const;\n};\n\nclass Bar : public Foo {\n  int foo() const;\n};\n\nvoid test() {\n  Bar().\n}"}}}
+Content-Length: 151
+
+{"jsonrpc":"2.0","id":2,"method":"textDocument/completion","params":{"textDocument":{"uri":"file:///main.cpp"},"position":{"line":11,"character":8}}}
+# CHECK: {"jsonrpc":"2.0","id":2,"result":[
+# CHECK-DAG: {"label":"foo() const","kind":2,"detail":"int","sortText":"200035foo","filterText":"foo","insertText":"foo","insertTextFormat":1}
+# CHECK-DAG: {"label":"bar() const","kind":2,"detail":"int","sortText":"000037bar","filterText":"bar","insertText":"bar","insertTextFormat":1}
+# CHECK-DAG: {"label":"Foo::foo() const","kind":2,"detail":"int","sortText":"000037foo","filterText":"foo","insertText":"foo","insertTextFormat":1}
+# CHECK: ]}
+Content-Length: 44
+
+{"jsonrpc":"2.0","id":4,"method":"shutdown"}