Make loplugin:bufferadd look through O[U]String::operator std::[u16]string_view

Change-Id: I79a32f64541a90b0b824f7721e8815c1e7c873ee
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/122788
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/compilerplugins/clang/bufferadd.cxx b/compilerplugins/clang/bufferadd.cxx
index bc8c7065b2a1..cf2b6a011b4a 100644
--- a/compilerplugins/clang/bufferadd.cxx
+++ b/compilerplugins/clang/bufferadd.cxx
@@ -347,6 +347,15 @@ bool BufferAdd::isSideEffectFree(Expr const* expr)
                     if (isSideEffectFree(callExpr->getArg(0)))
                         return true;
             }
+        // O[U]String::operator std::[u16]string_view:
+        if (auto const d = dyn_cast_or_null<CXXConversionDecl>(callExpr->getCalleeDecl()))
+        {
+            auto tc = loplugin::TypeCheck(d->getParent());
+            if (tc.Class("OString") || tc.Class("OUString"))
+            {
+                return true;
+            }
+        }
     }
 
     // sometimes we have a constructor call on the RHS
diff --git a/compilerplugins/clang/test/bufferadd.cxx b/compilerplugins/clang/test/bufferadd.cxx
index a9f28b13b55a..c8057a6f497b 100644
--- a/compilerplugins/clang/test/bufferadd.cxx
+++ b/compilerplugins/clang/test/bufferadd.cxx
@@ -52,6 +52,12 @@ void f5(OUStringBuffer& input)
     OUStringBuffer v(input);
     v.append("aaaa");
 }
+void f6(OString const& s)
+{
+    // expected-error@+1 {{convert this append sequence into a *String + sequence [loplugin:bufferadd]}}
+    OUStringBuffer b("foo");
+    b.append(OStringToOUString(s, RTL_TEXTENCODING_ASCII_US));
+}
 struct Footer
 {
     OStringBuffer m_descriptorStart;