2 files changed, 110 insertions, 0 deletions
diff --git a/compilerplugins/clang/constmove.cxx b/compilerplugins/clang/constmove.cxx
new file mode 100644
index 000000000000..63bafa188979
--- /dev/null
+++ b/compilerplugins/clang/constmove.cxx
@@ -0,0 +1,85 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+// Find occurrences of std::move on const-qualified types.  While there might theoretically be
+// legitimate uses for such (for which this plugin would generate false positives and would need to
+// be updated), in practice they tend to point at suspicious code that should be cleaned up in some
+// way.
+
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include "check.hxx"
+#include "plugin.hxx"
+
+namespace
+{
+class ConstMove final : public loplugin::FilteringPlugin<ConstMove>
+{
+public:
+    explicit ConstMove(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    bool preRun() override { return compiler.getLangOpts().CPlusPlus; }
+
+    void run() override
+    {
+        if (preRun())
+        {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+        }
+    }
+
+    bool VisitCallExpr(CallExpr const* expr)
+    {
+        if (ignoreLocation(expr))
+        {
+            return true;
+        }
+        auto const t = expr->getType();
+        if (!t.isConstQualified())
+        {
+            return true;
+        }
+        auto const d = expr->getDirectCallee();
+        if (d == nullptr)
+        {
+            return true;
+        }
+        if (!loplugin::DeclCheck(d).Function("move").StdNamespace())
+        {
+            return true;
+        }
+        switch (expr->getNumArgs())
+        {
+            case 0:
+                return true;
+            case 1:
+                break;
+            default:
+                if (!isa<CXXDefaultArgExpr>(expr->getArg(1)))
+                {
+                    return true;
+                }
+                break;
+        }
+        report(DiagnosticsEngine::Warning, "suspicious 'std::move' from %0 to const-qualified %1",
+               expr->getExprLoc())
+            << expr->getArg(0)->IgnoreImplicit()->getType() << t << expr->getSourceRange();
+        return true;
+    }
+};
+
+static loplugin::Plugin::Registration<ConstMove> constmove("constmove");
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/test/constmove.cxx b/compilerplugins/clang/test/constmove.cxx
new file mode 100644
index 000000000000..f6d2ed3ac9bf
--- /dev/null
+++ b/compilerplugins/clang/test/constmove.cxx
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <utility>
+
+struct S
+{
+};
+
+void f(S const& s1, S s2)
+{
+    // expected-error-re@+1 {{suspicious 'std::move' from 'const S' to const-qualified '{{.+}}' (aka 'const S') [loplugin:constmove]}}
+    S v1(std::move(s1));
+    (void)v1;
+    S v2(std::move(s2));
+    (void)v2;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */