[clang-format] Handle constrained auto in QualifierAlignment (#72251)

Fixed #69610.

Author: owenca

clang/lib/Format/QualifierAlignmentFixer.cpp

@@ -346,6 +346,9 @@ const FormatToken *LeftRightQualifierAlignmentFixer::analyzeRight(
       }
     }
 
+    if (Next->is(tok::kw_auto))
+      TypeToken = Next;
+
     // Place the Qualifier at the end of the list of qualifiers.
     while (isQualifier(TypeToken->getNextNonComment())) {
       // The case `volatile Foo::iter const` -> `Foo::iter const volatile`
@@ -446,6 +449,9 @@ const FormatToken *LeftRightQualifierAlignmentFixer::analyzeLeft(
         return false;
       }
 
+      if (Tok->endsSequence(tok::kw_auto, tok::identifier))
+        return false;
+
       return true;
     };
 

clang/unittests/Format/QualifierFixerTest.cpp

@@ -352,6 +352,11 @@ TEST_F(QualifierFixerTest, RightQualifier) {
   verifyFormat("auto const &ir = i;", "const auto &ir = i;", Style);
   verifyFormat("auto const *ip = &i;", "const auto *ip = &i;", Style);
 
+  verifyFormat("void f(Concept auto const &x);",
+               "void f(const Concept auto &x);", Style);
+  verifyFormat("void f(std::integral auto const &x);",
+               "void f(const std::integral auto &x);", Style);
+
   verifyFormat("Foo<Foo<int> const> P;\n#if 0\n#else\n#endif",
                "Foo<const Foo<int>> P;\n#if 0\n#else\n#endif", Style);
 
@@ -653,6 +658,11 @@ TEST_F(QualifierFixerTest, LeftQualifier) {
   verifyFormat("const auto &ir = i;", "auto const &ir = i;", Style);
   verifyFormat("const auto *ip = &i;", "auto const *ip = &i;", Style);
 
+  verifyFormat("void f(const Concept auto &x);",
+               "void f(Concept auto const &x);", Style);
+  verifyFormat("void f(const std::integral auto &x);",
+               "void f(std::integral auto const &x);", Style);
+
   verifyFormat("Foo<const Foo<int>> P;\n#if 0\n#else\n#endif",
                "Foo<Foo<int> const> P;\n#if 0\n#else\n#endif", Style);