[clang-format] Fix anonymous reference parameter with default value (#86254)

When enabling alignment of consecutive declarations and reference right
alignment, the needed space between `& ` and ` = ` is removed in the
following use case.

Problem (does not compile)
```
int    a(const Test    &= Test());
double b();
```

Expected:
```
int    a(const Test & = Test());
double b();
```

Test command:

```
echo "int    a(const Test& = Test()); double b();" | clang-format -style="{AlignConsecutiveDeclarations: true, ReferenceAlignment: Right}"
```

Author: rayroudc

clang/lib/Format/WhitespaceManager.cpp

@@ -464,10 +464,11 @@ AlignTokenSequence(const FormatStyle &Style, unsigned Start, unsigned End,
     if (i + 1 != Changes.size())
       Changes[i + 1].PreviousEndOfTokenColumn += Shift;
 
-    // If PointerAlignment is PAS_Right, keep *s or &s next to the token
+    // If PointerAlignment is PAS_Right, keep *s or &s next to the token,
+    // except if the token is equal, then a space is needed.
     if ((Style.PointerAlignment == FormatStyle::PAS_Right ||
          Style.ReferenceAlignment == FormatStyle::RAS_Right) &&
-        CurrentChange.Spaces != 0) {
+        CurrentChange.Spaces != 0 && CurrentChange.Tok->isNot(tok::equal)) {
       const bool ReferenceNotRightAligned =
           Style.ReferenceAlignment != FormatStyle::RAS_Right &&
           Style.ReferenceAlignment != FormatStyle::RAS_Pointer;

clang/unittests/Format/FormatTest.cpp

@@ -19066,6 +19066,11 @@ TEST_F(FormatTest, AlignConsecutiveDeclarations) {
   verifyFormat("int    a(int x);\n"
                "double b();",
                Alignment);
+  verifyFormat("int    a(const Test & = Test());\n"
+               "int    a1(int &foo, const Test & = Test());\n"
+               "int    a2(int &foo, const Test &name = Test());\n"
+               "double b();",
+               Alignment);
   verifyFormat("struct Test {\n"
                "  Test(const Test &) = default;\n"
                "  ~Test() = default;\n"
@@ -19102,6 +19107,13 @@ TEST_F(FormatTest, AlignConsecutiveDeclarations) {
                "    int  x,\n"
                "    bool y);",
                Alignment);
+  // Set ColumnLimit low so that we break the argument list in multiple lines.
+  Alignment.ColumnLimit = 35;
+  verifyFormat("int    a3(SomeTypeName1 &x,\n"
+               "          SomeTypeName2 &y,\n"
+               "          const Test & = Test());\n"
+               "double b();",
+               Alignment);
   Alignment.ColumnLimit = OldColumnLimit;
   // Ensure function pointers don't screw up recursive alignment
   verifyFormat("int    a(int x, void (*fp)(int y));\n"
@@ -19287,6 +19299,10 @@ TEST_F(FormatTest, AlignConsecutiveDeclarations) {
                "int    foobar;",
                AlignmentLeft);
 
+  verifyFormat("int    a(SomeType& foo, const Test& = Test());\n"
+               "double b();",
+               AlignmentLeft);
+
   // PAS_Middle
   FormatStyle AlignmentMiddle = Alignment;
   AlignmentMiddle.PointerAlignment = FormatStyle::PAS_Middle;
@@ -19347,6 +19363,10 @@ TEST_F(FormatTest, AlignConsecutiveDeclarations) {
                "int     foobar;",
                AlignmentMiddle);
 
+  verifyFormat("int    a(SomeType & foo, const Test & = Test());\n"
+               "double b();",
+               AlignmentMiddle);
+
   Alignment.AlignConsecutiveAssignments.Enabled = false;
   Alignment.AlignEscapedNewlines = FormatStyle::ENAS_DontAlign;
   verifyFormat("#define A \\\n"