Fix Issue 23977 - [REG2.102] cannot use getSymbolsByUDA on template s…

…truct with alias member

std/traits.d

@@ -8910,9 +8910,9 @@ template getSymbolsByUDA(alias symbol, alias attribute)
  static assert(is(getSymbolsByUDA!(X, X) == AliasSeq!()));
 }
 
-// https://issues.dlang.org/show_bug.cgi?id=23776
 @safe pure nothrow @nogc unittest
 {
+ // https://issues.dlang.org/show_bug.cgi?id=23776
  struct T
  {
  struct Tag {}
@@ -8932,6 +8932,18 @@ template getSymbolsByUDA(alias symbol, alias attribute)
  }
  alias xcomponents = getSymbolsByUDA!(X, X.Tag);
  static assert(xcomponents.length > 0);
+
+ // https://issues.dlang.org/show_bug.cgi?id=23977
+ struct S(string str)
+ {
+ alias strstr = str;
+
+ int i;
+ }
+
+ static struct A {}
+
+ assert((getSymbolsByUDA!(S!("a"), A)).length == 0);
 }
 
 // getSymbolsByUDA produces wrong result if one of the symbols having the UDA is a function
@@ -8991,7 +9003,10 @@ private template getSymbolsByUDAImpl(alias symbol, alias attribute, names...)
 
  // Filtering not compiled members such as alias of basic types.
  static if (isAliasSeq!member ||
- (isType!member && !isAggregateType!member && !is(member == enum)))
+ // exclude basic types and derived types
+ (isType!member && !isAggregateType!member && !is(member == enum)) ||
+ // exclude aliases to expressions such as string literals
+ __traits(compiles, { auto ex = member; }))
  {
  alias getSymbolsByUDAImpl = tail;
  }