Improve loplugin:redundantcast for sal_Int... vs. ::sal_Int...

Change-Id: I1548a76fdc03afee68f1e5c01bc665e616f2edf2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/86501
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 28 insertions, 1 deletions

diff --git a/compilerplugins/clang/check.cxx b/compilerplugins/clang/check.cxx
index be1b1f764eb1..472e296907b0 100644
--- a/compilerplugins/clang/check.cxx
+++ b/compilerplugins/clang/check.cxx
@@ -273,6 +273,19 @@ bool isExtraWarnUnusedType(clang::QualType type) {
 
 namespace {
 
+// Make sure Foo and ::Foo are considered equal:
+bool areSameSugaredType(clang::QualType type1, clang::QualType type2) {
+    auto t1 = type1.getLocalUnqualifiedType();
+    if (auto const et = llvm::dyn_cast<clang::ElaboratedType>(t1)) {
+        t1 = et->getNamedType();
+    }
+    auto t2 = type2.getLocalUnqualifiedType();
+    if (auto const et = llvm::dyn_cast<clang::ElaboratedType>(t2)) {
+        t2 = et->getNamedType();
+    }
+    return t1 == t2;
+}
+
 bool isArithmeticOp(clang::Expr const * expr) {
     expr = expr->IgnoreParenImpCasts();
     if (auto const e = llvm::dyn_cast<clang::BinaryOperator>(expr)) {
@@ -311,7 +324,7 @@ bool isOkToRemoveArithmeticCast(
     // suffix like L it could still be either long or long long):
     if ((t1->isIntegralType(context)
          || t1->isRealFloatingType())
-        && ((t1.getLocalUnqualifiedType() != t2.getLocalUnqualifiedType()
+        && ((!areSameSugaredType(t1, t2)
              && (loplugin::TypeCheck(t1).Typedef()
                  || loplugin::TypeCheck(t2).Typedef()
                  || llvm::isa<clang::DecltypeType>(t1) || llvm::isa<clang::DecltypeType>(t2)))
diff --git a/compilerplugins/clang/test/redundantcast.cxx b/compilerplugins/clang/test/redundantcast.cxx
index 2ffd8f93c96f..03ce47796d65 100644
--- a/compilerplugins/clang/test/redundantcast.cxx
+++ b/compilerplugins/clang/test/redundantcast.cxx
@@ -7,8 +7,12 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#include <sal/config.h>
+
 #include <cstddef>
 
+#include <sal/types.h>
+
 #include "redundantcast.hxx"
 
 void f1(char *) {}
@@ -418,6 +422,15 @@ auto testNullFunctionPointer(int i, F p) {
     }
 }
 
+void testSalIntTypes() {
+    sal_Int16 const n = 0;
+    (void) static_cast<sal_Int16>(n); // expected-error-re {{static_cast from 'const sal_Int16' (aka 'const {{.+}}') lvalue to 'sal_Int16' (aka '{{.+}}') prvalue is redundant or should be written as an explicit construction of a temporary [loplugin:redundantcast]}}
+    (void) static_cast<::sal_Int16>(n); // expected-error-re {{static_cast from 'const sal_Int16' (aka 'const {{.+}}') lvalue to '::sal_Int16' (aka '{{.+}}') prvalue is redundant or should be written as an explicit construction of a temporary [loplugin:redundantcast]}}
+    (void) static_cast<short>(n); // doesn't warn, even if 'sal_Int16' is 'short'
+    using Other = sal_Int16;
+    (void) static_cast<Other>(n); // doesn't warn either
+}
+
 int main() {
     testConstCast();
     testStaticCast();
@@ -428,6 +441,7 @@ int main() {
     testDynamicCast();
     testIntermediaryStaticCast();
     testArrayDecay();
+    testSalIntTypes();
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */