[clang-format] Indent TT_CtorInitializerColon after requires clauses

[HazardyKnusperkeks]

Summary

Fixes https://github.com/llvm/llvm-project/issues/56215

clang/lib/Format/ContinuationIndenter.cpp

if (Current.is(TT_RequiresClause)) {
     switch (Style.RequiresClausePosition) {
     case FormatStyle::RCPS_OwnLine:
     case FormatStyle::RCPS_WithFollowing:
       return CurrentState.Indent;
     default:
       break;
     }
   }
+  if (NextNonComment->isOneOf(TT_CtorInitializerColon, TT_InheritanceColon,
+                              TT_InheritanceComma)) {
+    return State.FirstIndent + Style.ConstructorInitializerIndentWidth;
+  }
   if ((PreviousNonComment &&
        (PreviousNonComment->ClosesTemplateDeclaration ||
         PreviousNonComment->ClosesRequiresClause ||
         PreviousNonComment->isOneOf(
             TT_AttributeParen, TT_AttributeSquare, TT_FunctionAnnotationRParen,
             TT_JavaAnnotation, TT_LeadingJavaAnnotation))) ||
       (!Style.IndentWrappedFunctionNames &&
        NextNonComment->isOneOf(tok::kw_operator, TT_FunctionDeclarationName))) {
unsigned ContinuationIndenter::getNewLineColumn(const LineState &State) {
   if (PreviousNonComment && PreviousNonComment->is(TT_CtorInitializerColon) &&
       Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon) {
     return CurrentState.Indent;
   }
   if (PreviousNonComment && PreviousNonComment->is(TT_InheritanceColon) &&
       Style.BreakInheritanceList == FormatStyle::BILS_AfterColon) {
     return CurrentState.Indent;
   }
-  if (NextNonComment->isOneOf(TT_CtorInitializerColon, TT_InheritanceColon,
-                              TT_InheritanceComma)) {
-    return State.FirstIndent + Style.ConstructorInitializerIndentWidth;
-  }
   if (Previous.is(tok::r_paren) && !Current.isBinaryOperator() &&
       !Current.isOneOf(tok::colon, tok::comment)) {
     return ContinuationIndent;
   }
   if (Current.is(TT_ProtoExtensionLSquare))
     return CurrentState.Indent;
   if (Current.isBinaryOperator() && CurrentState.UnindentOperator) {
     return CurrentState.Indent - Current.Tok.getLength() -

clang/unittests/Format/FormatTest.cpp

verifyFormat(
       "           and is_callable_v<hash<T>(T)>\n"
       "           and is_same_v<size_t, decltype(hash<T>(declval<T>()))>\n"
       "           and is_same_v<size_t, decltype(hash<T>(declval<T &>()))>\n"
       "           and is_same_v<size_t, decltype(hash<T>(declval<const T "
       "&>()))>\n"
       "struct S {};",
       Style);
 
+  Style = getLLVMStyle();
+  Style.ConstructorInitializerIndentWidth = 4;
+  Style.BreakConstructorInitializers = FormatStyle::BCIS_BeforeColon;
+  Style.PackConstructorInitializers = FormatStyle::PCIS_Never;
+  verifyFormat("constexpr Foo(Foo const &other)\n"
+               "  requires std::is_copy_constructible<T>\n"
+               "    : value{other.value} {\n"
+               "  do_magic();\n"
+               "  do_more_magic();\n"
+               "}",
+               Style);
+
   // Not a clause, but we once hit an assert.
   verifyFormat("#if 0\n"
                "#else\n"
                "foo();\n"
                "#endif\n"
                "bar(requires);");
 }