1 files changed, 76 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-tidy/readability/SimplifySubscriptExprCheck.cpp b/clang-tools-extra/clang-tidy/readability/SimplifySubscriptExprCheck.cpp
new file mode 100644
index 00000000000..28cc576dd5c
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+++ b/clang-tools-extra/clang-tidy/readability/SimplifySubscriptExprCheck.cpp
@@ -0,0 +1,76 @@
+//===--- SimplifySubscriptExprCheck.cpp - clang-tidy-----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SimplifySubscriptExprCheck.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+static const char kDefaultTypes[] =
+    "::std::basic_string;::std::basic_string_view;::std::vector;::std::array";
+
+SimplifySubscriptExprCheck::SimplifySubscriptExprCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context), Types(utils::options::parseStringList(
+                                         Options.get("Types", kDefaultTypes))) {
+}
+
+void SimplifySubscriptExprCheck::registerMatchers(MatchFinder *Finder) {
+  if (!getLangOpts().CPlusPlus)
+    return;
+
+  const auto TypesMatcher = hasUnqualifiedDesugaredType(
+      recordType(hasDeclaration(cxxRecordDecl(hasAnyName(
+          llvm::SmallVector<StringRef, 8>(Types.begin(), Types.end()))))));
+
+  Finder->addMatcher(
+      arraySubscriptExpr(hasBase(ignoringParenImpCasts(
+          cxxMemberCallExpr(
+              has(memberExpr().bind("member")),
+              on(hasType(qualType(
+                  unless(anyOf(substTemplateTypeParmType(),
+                               hasDescendant(substTemplateTypeParmType()))),
+                  anyOf(TypesMatcher, pointerType(pointee(TypesMatcher)))))),
+              callee(namedDecl(hasName("data"))))
+              .bind("call")))),
+      this);
+}
+
+void SimplifySubscriptExprCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *Call = Result.Nodes.getNodeAs<CXXMemberCallExpr>("call");
+  if (Result.Context->getSourceManager().isMacroBodyExpansion(
+          Call->getExprLoc()))
+    return;
+
+  const auto *Member = Result.Nodes.getNodeAs<MemberExpr>("member");
+  auto DiagBuilder =
+      diag(Member->getMemberLoc(),
+           "accessing an element of the container does not require a call to "
+           "'data()'; did you mean to use 'operator[]'?");
+  if (Member->isArrow())
+    DiagBuilder << FixItHint::CreateInsertion(Member->getLocStart(), "(*")
+                << FixItHint::CreateInsertion(Member->getOperatorLoc(), ")");
+  DiagBuilder << FixItHint::CreateRemoval(
+      {Member->getOperatorLoc(), Call->getLocEnd()});
+}
+
+void SimplifySubscriptExprCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "Types", utils::options::serializeStringList(Types));
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang