Avoid unhelpful loplugin:stringview from implicit conversions

> compilerplugins/clang/test/stringview.cxx Line 149: instead of an 'rtl::OString' constructed from a 'const rtl::OStringLiteral<4>', pass a 'std::string_view' [loplugin:stringview]
> compilerplugins/clang/test/stringview.cxx Line 150: instead of an 'rtl::OUString' constructed from a 'const rtl::OUStringLiteral<4>', pass a 'std::u16string_view' [loplugin:stringview]

(see the discussion at <https://gerrit.libreoffice.org/c/core/+/124950>
"operator==(OString, OStringLiteral)")

Change-Id: I5481bef8b8bad7bf9bdf4fff29161f0809051f2b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/124990
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

2 files changed, 19 insertions, 12 deletions

diff --git a/compilerplugins/clang/stringview.cxx b/compilerplugins/clang/stringview.cxx
index 4043d7a67e60..b3a0323d2923 100644
--- a/compilerplugins/clang/stringview.cxx
+++ b/compilerplugins/clang/stringview.cxx
@@ -75,18 +75,18 @@ bool StringView::VisitCXXOperatorCallExpr(CXXOperatorCallExpr const* cxxOperator
     auto op = cxxOperatorCallExpr->getOperator();
     if (op == OO_Plus && cxxOperatorCallExpr->getNumArgs() == 2)
     {
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(0)));
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(1)));
+        handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(0));
+        handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(1));
     }
     if (compat::isComparisonOp(cxxOperatorCallExpr))
     {
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(0)));
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(1)));
+        handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(0));
+        handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(1));
     }
     else if (op == OO_PlusEqual)
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(1)));
+        handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(1));
     else if (op == OO_Subscript)
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(0)));
+        handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(0));
     else if (op == OO_Equal)
     {
         if (loplugin::TypeCheck(cxxOperatorCallExpr->getType())
@@ -98,7 +98,7 @@ bool StringView::VisitCXXOperatorCallExpr(CXXOperatorCallExpr const* cxxOperator
                    .Namespace("rtl")
                    .GlobalNamespace())
         {
-            handleSubExprThatCouldBeView(compat::IgnoreImplicit(cxxOperatorCallExpr->getArg(1)));
+            handleSubExprThatCouldBeView(cxxOperatorCallExpr->getArg(1));
         }
     }
     return true;
@@ -130,7 +130,8 @@ bool StringView::VisitImplicitCastExpr(ImplicitCastExpr const* expr)
 
 void StringView::handleSubExprThatCouldBeView(Expr const* subExpr)
 {
-    auto const e = subExpr->IgnoreParens();
+    auto const e0 = compat::IgnoreImplicit(subExpr);
+    auto const e = e0->IgnoreParens();
     auto const tc = loplugin::TypeCheck(e->getType());
     if (!(tc.Class("OString").Namespace("rtl").GlobalNamespace()
           || tc.Class("OUString").Namespace("rtl").GlobalNamespace()))
@@ -139,7 +140,10 @@ void StringView::handleSubExprThatCouldBeView(Expr const* subExpr)
     }
     if (auto const e1 = dyn_cast<CXXConstructExpr>(e))
     {
-        handleCXXConstructExpr(e1);
+        if (e0 == subExpr)
+        {
+            handleCXXConstructExpr(e1);
+        }
     }
     else if (auto const e2 = dyn_cast<CXXFunctionalCastExpr>(e))
     {
@@ -301,11 +305,11 @@ bool StringView::VisitCXXMemberCallExpr(CXXMemberCallExpr const* expr)
     auto const dc = loplugin::DeclCheck(expr->getMethodDecl());
     if (dc.Function("append") || dc.Function("indexOf") || dc.Function("lastIndexOf"))
     {
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(expr->getArg(0)));
+        handleSubExprThatCouldBeView(expr->getArg(0));
     }
     else if (dc.Function("insert"))
     {
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(expr->getArg(1)));
+        handleSubExprThatCouldBeView(expr->getArg(1));
     }
     return true;
 }
@@ -330,7 +334,7 @@ bool StringView::VisitCXXConstructExpr(CXXConstructExpr const* expr)
         return true;
     }
     if (expr->getNumArgs() > 0)
-        handleSubExprThatCouldBeView(compat::IgnoreImplicit(expr->getArg(0)));
+        handleSubExprThatCouldBeView(expr->getArg(0));
     return true;
 }
 
diff --git a/compilerplugins/clang/test/stringview.cxx b/compilerplugins/clang/test/stringview.cxx
index 63c8548a0b45..c03fbb84cb32 100644
--- a/compilerplugins/clang/test/stringview.cxx
+++ b/compilerplugins/clang/test/stringview.cxx
@@ -145,6 +145,9 @@ void f5(char const* s1, sal_Int32 n1, char16_t const* s2, sal_Int32 n2, OString
     call_view(OUString(OUString::number(0)));
     // expected-error-re@+1 {{instead of an 'rtl::OUString' constructed from a 'typename std::enable_if_t<ToStringHelper<OUString>::allowOUStringConcat && ToStringHelper<OUString>::allowOUStringConcat, OUStringConcat<OUString, OUString>{{ ?}}>' (aka 'rtl::OUStringConcat<rtl::OUString, rtl::OUString>'), pass a 'std::u16string_view' via 'rtl::OUStringConcatenation' [loplugin:stringview]}}
     call_view(OUString(s4 + s4));
+
+    (void)(s3 == l1);
+    (void)(s4 == l2);
 }
 
 void f5(OUString s)