[clang] [clang-tools-extra] [clang-tidy] Added new check to detect redundant inline keyword (PR #73069)

[Félix-Antoine Constantin via cfe-commits]

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@@ -0,0 +1,109 @@
+//===--- RedundantInlineSpecifierCheck.cpp - clang-tidy--------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "RedundantInlineSpecifierCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclTemplate.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Lex/Token.h"
+
+#include "../utils/LexerUtils.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::readability {
+
+AST_POLYMORPHIC_MATCHER(isInlineSpecified,
+                        AST_POLYMORPHIC_SUPPORTED_TYPES(FunctionDecl,
+                                                        VarDecl)) {
+  if (const auto *FD = dyn_cast<FunctionDecl>(&Node))
+    return FD->isInlineSpecified();
+  if (const auto *VD = dyn_cast<VarDecl>(&Node))
+    return VD->isInlineSpecified();
+  llvm_unreachable("Not a valid polymorphic type");
+}
+
+static std::optional<SourceLocation>
+getInlineTokenLocation(SourceRange RangeLocation, const SourceManager &Sources,
+                       const LangOptions &LangOpts) {
+  Token FirstToken;
+  Lexer::getRawToken(RangeLocation.getBegin(), FirstToken, Sources, LangOpts,
+                     true);
+  std::optional<Token> CurrentToken = FirstToken;
+  while (CurrentToken && CurrentToken->getLocation() < RangeLocation.getEnd() &&
+         CurrentToken->isNot(tok::eof)) {
+    if (CurrentToken->is(tok::raw_identifier) &&
+        CurrentToken->getRawIdentifier() == "inline")
+      return CurrentToken->getLocation();
+
+    CurrentToken =
+        Lexer::findNextToken(CurrentToken->getLocation(), Sources, LangOpts);
+  }
+  return std::nullopt;
+}
+
+void RedundantInlineSpecifierCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      functionDecl(unless(isExpansionInSystemHeader()), isInlineSpecified(),
+                   anyOf(isConstexpr(), isDeleted(),
+                         allOf(isDefinition(), hasAncestor(recordDecl()))))
+          .bind("fun_decl"),
+      this);
+
+  Finder->addMatcher(
+      varDecl(isInlineSpecified(),
+              anyOf(allOf(isConstexpr(), unless(isStaticStorageClass())),
+                    hasAncestor(recordDecl())))
+          .bind("var_decl"),
+      this);
+
+  Finder->addMatcher(
+      functionTemplateDecl(has(functionDecl(isInlineSpecified())))
----------------
felix642 wrote:

Well, I think that it's fair to emit a warning if either a forward declaration of a function definition has a redundant inline specifier. In both case we want to suggest to remove it don't we ? 

https://github.com/llvm/llvm-project/pull/73069