[clang-format] Correctly limit formatted ranges when specifying qualifier alignment

The qualifier alignment fixer appeared to ignore any ranges specified for limiting formatting.
This change ensures that it only formats affected lines to avoid unexpected changes.

Fixes #54888.

Differential Revision: https://reviews.llvm.org/D149643

1 files changed, 23 insertions, 0 deletions

diff --git a/clang/unittests/Format/QualifierFixerTest.cpp b/clang/unittests/Format/QualifierFixerTest.cpp
index 76800b3fc8e3..9760c80dcc61 100755
--- a/clang/unittests/Format/QualifierFixerTest.cpp
+++ b/clang/unittests/Format/QualifierFixerTest.cpp
@@ -1343,6 +1343,29 @@ TEST_F(QualifierFixerTest, TemplatesLeft) {
                "TemplateType<Container const> t;", Style);
 }
 
+TEST_F(QualifierFixerTest, Ranges) {
+  FormatStyle Style = getLLVMStyle();
+  Style.QualifierAlignment = FormatStyle::QAS_Custom;
+  Style.QualifierOrder = {"const", "volatile", "type"};
+
+  // Only the first line should be formatted; the second should remain as is.
+  verifyFormat("template <typename T> const Foo f();\n"
+               "template <typename T> Foo const f();",
+               "template <typename T> Foo const f();\n"
+               "template <typename T> Foo const f();",
+               Style, {tooling::Range(0, 36)});
+
+  // Only the middle line should be formatted; the first and last should remain
+  // as is.
+  verifyFormat("template <typename T> Foo const f();\n"
+               "template <typename T> const Foo f();\n"
+               "template <typename T> Foo const f();",
+               "template <typename T> Foo const f();\n"
+               "template <typename T> Foo const f();\n"
+               "template <typename T> Foo const f();",
+               Style, {tooling::Range(37, 36)});
+}
+
 } // namespace
 } // namespace test
 } // namespace format