Add AlignAttribute.isExplicitDefault

Author: 0-v-0

src/dparse/ast.d

@@ -612,6 +612,9 @@ final class AlignAttribute : BaseNode
     }
     mixin OpEquals;
     /** */ ExpressionNode assignExpression;
+    /** */ bool isExplicitDefault() inout @property @safe nothrow @nogc pure {
+        return tokens.length > 2 && tokens[2] == tok!"default";
+    }
 }
 
 ///

src/dparse/formatter.d

@@ -206,7 +206,9 @@ class Formatter(Sink)
         **/
 
         put("align");
-        if (alignAttribute.assignExpression !is null)
+        if (alignAttribute.isExplicitDefault)
+            put("(default)");
+        else if (alignAttribute.assignExpression !is null)
         {
             put("(");
             format(alignAttribute.assignExpression);
@@ -4407,4 +4409,5 @@ z /// Documentation for z
     testFormatNode!(VariableDeclaration)("auto x = i` $(b) is $(b)!`;");
     testFormatNode!(VariableDeclaration)("auto x = iq{ $(b) is $(b)!};");
     testFormatNode!(VariableDeclaration)("auto x = iq{{$('$')}};");
+    testFormatNode!(AlignAttribute)(`align(default) struct S {}`, `align(default)`);
 }