================
@@ -0,0 +1,419 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 "UseStructuredBindingCheck.h"
+#include "../utils/DeclRefExprUtils.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+
+static constexpr const char *DefaultPairTypes = "std::pair";
+static constexpr llvm::StringLiteral PairDeclName = "PairVarD";
+static constexpr llvm::StringLiteral PairVarTypeName = "PairVarType";
+static constexpr llvm::StringLiteral FirstVarDeclName = "FirstVarDecl";
+static constexpr llvm::StringLiteral SecondVarDeclName = "SecondVarDecl";
+static constexpr llvm::StringLiteral FirstDeclStmtName = "FirstDeclStmt";
+static constexpr llvm::StringLiteral SecondDeclStmtName = "SecondDeclStmt";
+static constexpr llvm::StringLiteral FirstTypeName = "FirstType";
+static constexpr llvm::StringLiteral SecondTypeName = "SecondType";
+static constexpr llvm::StringLiteral ScopeBlockName = "ScopeBlock";
+static constexpr llvm::StringLiteral StdTieAssignStmtName = "StdTieAssign";
+static constexpr llvm::StringLiteral StdTieExprName = "StdTieExpr";
+static constexpr llvm::StringLiteral ForRangeStmtName = "ForRangeStmt";
+
+/// Try to match exactly two VarDecl inside two DeclStmts, and set binding for
+/// the used DeclStmts.
+static bool
+matchTwoVarDecl(const DeclStmt *DS1, const DeclStmt *DS2,
+ ast_matchers::internal::Matcher<VarDecl> InnerMatcher1,
+ ast_matchers::internal::Matcher<VarDecl> InnerMatcher2,
+ internal::ASTMatchFinder *Finder,
+ internal::BoundNodesTreeBuilder *Builder) {
+ SmallVector<std::pair<const VarDecl *, const DeclStmt *>, 2> Vars;
+ auto CollectVarsInDeclStmt = [&Vars](const DeclStmt *DS) -> bool {
+ if (!DS)
+ return true;
+
+ for (const auto *VD : DS->decls()) {
+ if (Vars.size() == 2)
+ return false;
+
+ if (const auto *Var = dyn_cast<VarDecl>(VD))
+ Vars.emplace_back(Var, DS);
+ else
+ return false;
+ }
+
+ return true;
+ };
+
+ // If we already get two VarDecls, then don't need to collect from DS2.
+ if (!CollectVarsInDeclStmt(DS1) ||
+ (Vars.size() != 2 && !CollectVarsInDeclStmt(DS2)) || Vars.size() != 2)
+ return false;
+
+ if (InnerMatcher1.matches(*Vars[0].first, Finder, Builder) &&
+ InnerMatcher2.matches(*Vars[1].first, Finder, Builder)) {
+ Builder->setBinding(FirstDeclStmtName,
+ clang::DynTypedNode::create(*Vars[0].second));
+ if (Vars[0].second != Vars[1].second)
+ Builder->setBinding(SecondDeclStmtName,
+ clang::DynTypedNode::create(*Vars[1].second));
+ return true;
+ }
+
+ return false;
+}
+
+namespace {
+/// What qualifiers and specifiers are used to create structured binding
+/// declaration, it only supports the following four cases now.
+enum TransferType : uint8_t {
+ TT_ByVal,
+ TT_ByConstVal,
+ TT_ByRef,
+ TT_ByConstRef
+};
+
+/// Matches a Stmt whose parent is a CompoundStmt, and which is directly
+/// following two VarDecls matching the inner matcher, at the same time set
+/// binding for the CompoundStmt.
+AST_MATCHER_P2(Stmt, hasPreTwoVarDecl,
ast_matchers::internal::Matcher<VarDecl>,
+ InnerMatcher1, ast_matchers::internal::Matcher<VarDecl>,
+ InnerMatcher2) {
+ DynTypedNodeList Parents = Finder->getASTContext().getParents(Node);
+ if (Parents.size() != 1)
+ return false;
+
+ auto *C = Parents[0].get<CompoundStmt>();
+ if (!C)
+ return false;
+
+ const auto I =
+ llvm::find(llvm::make_range(C->body_rbegin(), C->body_rend()), &Node);
+ assert(I != C->body_rend() && "C is parent of Node");
+ if ((I + 1) == C->body_rend())
+ return false;
+
+ const auto *DS2 = dyn_cast<DeclStmt>(*(I + 1));
+ if (!DS2)
+ return false;
+
+ const DeclStmt *DS1 = (!DS2->isSingleDecl() || ((I + 2) == C->body_rend())
+ ? nullptr
+ : dyn_cast<DeclStmt>(*(I + 2)));
+ if (DS1 && !DS1->isSingleDecl())
+ return false;
----------------
flovent wrote:
```
if (DS1 && !DS1->isSingleDecl())
return false;
```
This code is added in latest commit to avoid:
```
int a, b;
XYZ otherV = call();
std::tie(a, b) = ...; // Should not warn
```
Because we should accpet that in other two cases, so i handle it specificly in
`hasPreTwoVarDecl`:
```
Pair p = ...; // warn
int a = p.first, b = p.second;
XYZ otherV = call();
```
But when i look at these lines of code again, it's a bit complicated indeed,
i'll see how to make it more clear.
https://github.com/llvm/llvm-project/pull/158462
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