3 files changed, 67 insertions, 2 deletions

diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
index 36d0f21ed09..df438b4836d 100644
--- a/clang-tools-extra/clangd/CodeComplete.cpp
+++ b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -1413,8 +1413,17 @@ CompletionItem CodeCompletion::render(const CodeCompleteOptions &Opts) const {
       LSP.additionalTextEdits.push_back(FixIt);
     }
   }
-  if (Opts.EnableSnippets)
-    LSP.textEdit->newText += SnippetSuffix;
+  if (Opts.EnableSnippets && !SnippetSuffix.empty()) {
+    if (!Opts.EnableFunctionArgSnippets &&
+        ((Kind == CompletionItemKind::Function) ||
+         (Kind == CompletionItemKind::Method)) &&
+        (SnippetSuffix.front() == '(') && (SnippetSuffix.back() == ')'))
+      // Check whether function has any parameters or not.
+      LSP.textEdit->newText += SnippetSuffix.size() > 2 ? "(${0})" : "()";
+    else
+      LSP.textEdit->newText += SnippetSuffix;
+  }
+
   // FIXME(kadircet): Do not even fill insertText after making sure textEdit is
   // compatible with most of the editors.
   LSP.insertText = LSP.textEdit->newText;
diff --git a/clang-tools-extra/clangd/CodeComplete.h b/clang-tools-extra/clangd/CodeComplete.h
index 9ef2b1fbaf5..1d85a66ec44 100644
--- a/clang-tools-extra/clangd/CodeComplete.h
+++ b/clang-tools-extra/clangd/CodeComplete.h
@@ -82,6 +82,10 @@ struct CodeCompleteOptions {
   /// Include completions that require small corrections, e.g. change '.' to
   /// '->' on member access etc.
   bool IncludeFixIts = false;
+
+  /// Whether to generate snippets for function arguments on code-completion.
+  /// Needs snippets to be enabled as well.
+  bool EnableFunctionArgSnippets = true;
 };
 
 // Semi-structured representation of a code-complete suggestion for our C++ API.
diff --git a/clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp b/clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp
index 5933bb5ff08..3fce86626d8 100644
--- a/clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp
+++ b/clang-tools-extra/unittests/clangd/CodeCompleteTests.cpp
@@ -1648,6 +1648,58 @@ TEST(SignatureHelpTest, IndexDocumentation) {
                         SigDoc("Doc from sema"))));
 }
 
+TEST(CompletionTest, RenderWithSnippetsForFunctionArgsDisabled) {
+  CodeCompleteOptions Opts;
+  Opts.EnableFunctionArgSnippets = true;
+  {
+    CodeCompletion C;
+    C.RequiredQualifier = "Foo::";
+    C.Name = "x";
+    C.SnippetSuffix = "()";
+
+    auto R = C.render(Opts);
+    EXPECT_EQ(R.textEdit->newText, "Foo::x");
+    EXPECT_EQ(R.insertTextFormat, InsertTextFormat::PlainText);
+  }
+
+  Opts.EnableSnippets = true;
+  Opts.EnableFunctionArgSnippets = false;
+  {
+    CodeCompletion C;
+    C.RequiredQualifier = "Foo::";
+    C.Name = "x";
+    C.SnippetSuffix = "";
+
+    auto R = C.render(Opts);
+    EXPECT_EQ(R.textEdit->newText, "Foo::x");
+    EXPECT_EQ(R.insertTextFormat, InsertTextFormat::Snippet);
+  }
+
+  {
+    CodeCompletion C;
+    C.RequiredQualifier = "Foo::";
+    C.Name = "x";
+    C.SnippetSuffix = "()";
+    C.Kind = CompletionItemKind::Method;
+
+    auto R = C.render(Opts);
+    EXPECT_EQ(R.textEdit->newText, "Foo::x()");
+    EXPECT_EQ(R.insertTextFormat, InsertTextFormat::Snippet);
+  }
+
+  {
+    CodeCompletion C;
+    C.RequiredQualifier = "Foo::";
+    C.Name = "x";
+    C.SnippetSuffix = "(${0:bool})";
+    C.Kind = CompletionItemKind::Function;
+
+    auto R = C.render(Opts);
+    EXPECT_EQ(R.textEdit->newText, "Foo::x(${0})");
+    EXPECT_EQ(R.insertTextFormat, InsertTextFormat::Snippet);
+  }
+}
+
 } // namespace
 } // namespace clangd
 } // namespace clang