[clangd] Skip informative qualifier chunks.

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.

Reviewers: bkramer, krasimir, rwols

Reviewed By: rwols

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D38083

llvm-svn: 314445

clang-tools-extra/clangd/ClangdUnit.cpp

@@ -409,6 +409,11 @@ private:
 
 }; // CompletionItemsCollector
 
+bool isInformativeQualifierChunk(CodeCompletionString::Chunk const &Chunk) {
+  return Chunk.Kind == CodeCompletionString::CK_Informative &&
+         StringRef(Chunk.Text).endswith("::");
+}
+
 class PlainTextCompletionItemsCollector final
     : public CompletionItemsCollector {
 
@@ -421,6 +426,11 @@ 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.
@@ -453,6 +463,11 @@ private:
                      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

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

@@ -0,0 +1,18 @@
+# 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"}