Fix string constants for standalone sys

crates/libs/bindgen/src/constants.rs

@@ -12,7 +12,11 @@ pub fn gen(gen: &Gen, def: Field) -> TokenStream {
 
         if ty == constant_type {
             if ty == Type::String {
-                let crate_name = gen.crate_name();
+                let crate_name: TokenStream = if gen.sys && !gen.standalone {
+                    "::windows_sys::core::".into()
+                } else {
+                    "::windows_core::".into()
+                };
                 if gen.reader.field_is_ansi(def) {
                     let value = gen.value(&gen.reader.constant_value(constant));
                     quote! {

crates/libs/bindgen/src/standalone.rs

@@ -67,8 +67,15 @@ fn standalone_imp(gen: &mut Gen, names: &[&str]) -> String {
             .find(|field| gen.reader.field_name(*field) == type_name.name)
         {
             constants.insert(field);
-            gen.reader
-                .type_collect_standalone(&gen.reader.field_type(field, None), &mut types);
+
+            let ft = gen.reader.field_type(field, None);
+
+            // String normally gets resolved to HSTRING, but since macros
+            // from windows_core/windows_sys::core are used to create the
+            // string literals we can skip the type collection
+            if ft != Type::String {
+                gen.reader.type_collect_standalone(&ft, &mut types);
+            }
         }
 
         if let Some(field) = gen

crates/tests/standalone/build.rs

@@ -118,7 +118,18 @@ fn main() {
     write_sys(
         "src/b_overloads.rs",
         &["Windows.Win32.NetworkManagement.NetManagement.AE_RESACCESS"],
-    )
+    );
+
+    // Ensures that string constants are written correctly
+    write_sys(
+        "src/b_string_constants.rs",
+        &[
+            // utf-16
+            "Windows.Win32.Devices.Enumeration.Pnp.ADDRESS_FAMILY_VALUE_NAME",
+            // ansi
+            "Windows.Win32.Media.Multimedia.JOY_CONFIGCHANGED_MSGSTRING",
+        ],
+    );
 }
 
 fn write_sys(filename: &str, apis: &[&str]) {

crates/tests/standalone/src/b_string_constants.rs

@@ -0,0 +1,14 @@
+// Bindings generated by `windows-bindgen` 0.49.0
+
+#![allow(
+    non_snake_case,
+    non_upper_case_globals,
+    non_camel_case_types,
+    dead_code,
+    clippy::all
+)]
+pub const ADDRESS_FAMILY_VALUE_NAME: ::windows_core::PCWSTR = ::windows_core::w!("AddressFamily");
+pub const JOY_CONFIGCHANGED_MSGSTRING: ::windows_core::PCSTR =
+    ::windows_core::s!("MSJSTICK_VJOYD_MSGSTR");
+pub type PCSTR = *const u8;
+pub type PCWSTR = *const u16;

crates/tests/standalone/src/lib.rs

@@ -19,6 +19,7 @@ mod b_pcwstr;
 mod b_pstr;
 mod b_pwstr;
 mod b_std;
+mod b_string_constants;
 mod b_stringable;
 mod b_test;
 mod b_unknown;