[clang-format] Fix a bug in ContinuationIndenter (llvm#66354)

See https://reviews.llvm.org/D136154#3890747 for context.

Fixes part of llvm#58592.

Author: owenca

clang/lib/Format/ContinuationIndenter.cpp

@@ -876,15 +876,15 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
                  FormatStyle::BCIS_AfterColon) {
     CurrentState.Indent = State.Column;
     CurrentState.LastSpace = State.Column;
-  } else if ((Previous.isOneOf(TT_BinaryOperator, TT_ConditionalExpr,
-                               TT_CtorInitializerColon)) &&
+  } else if (Previous.isOneOf(TT_ConditionalExpr, TT_CtorInitializerColon)) {
+    CurrentState.LastSpace = State.Column;
+  } else if (Previous.is(TT_BinaryOperator) &&
              ((Previous.getPrecedence() != prec::Assignment &&
                (Previous.isNot(tok::lessless) || Previous.OperatorIndex != 0 ||
                 Previous.NextOperator)) ||
               Current.StartsBinaryExpression)) {
     // Indent relative to the RHS of the expression unless this is a simple
-    // assignment without binary expression on the RHS. Also indent relative to
-    // unary operators and the colons of constructor initializers.
+    // assignment without binary expression on the RHS.
     if (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None)
       CurrentState.LastSpace = State.Column;
   } else if (Previous.is(TT_InheritanceColon)) {

clang/unittests/Format/FormatTest.cpp

@@ -7108,6 +7108,29 @@ TEST_F(FormatTest, ExpressionIndentationBreakingBeforeOperators) {
                "(someOtherLongishConditionPart1 || "
                "someOtherEvenLongerNestedConditionPart2);",
                Style);
+
+  Style = getLLVMStyleWithColumns(20);
+  Style.AlignAfterOpenBracket = FormatStyle::BAS_AlwaysBreak;
+  Style.BinPackParameters = false;
+  Style.BreakBeforeBinaryOperators = FormatStyle::BOS_NonAssignment;
+  Style.ContinuationIndentWidth = 2;
+  verifyFormat("struct Foo {\n"
+               "  Foo(\n"
+               "    int arg1,\n"
+               "    int arg2)\n"
+               "      : Base(\n"
+               "          arg1,\n"
+               "          arg2) {}\n"
+               "};",
+               Style);
+  verifyFormat("return abc\n"
+               "         ? foo(\n"
+               "             a,\n"
+               "             b,\n"
+               "             bar(\n"
+               "               abc))\n"
+               "         : g(abc);",
+               Style);
 }
 
 TEST_F(FormatTest, ExpressionIndentationStrictAlign) {