respect $module argument to global-variable-exists

src/builtin/functions/meta.rs

@@ -99,15 +99,39 @@ pub(crate) fn global_variable_exists(
     mut args: CallArgs,
     parser: &mut Parser<'_>,
 ) -> SassResult<Value> {
-    args.max_args(1)?;
-    match args.get_err(0, "name")? {
-        Value::String(s, _) => Ok(Value::bool(parser.global_scope.var_exists(s.into()))),
-        v => Err((
-            format!("$name: {} is not a string.", v.inspect(args.span())?),
-            args.span(),
-        )
-            .into()),
-    }
+    args.max_args(2)?;
+
+    let name: Identifier = match args.get_err(0, "name")? {
+        Value::String(s, _) => s.into(),
+        v => {
+            return Err((
+                format!("$name: {} is not a string.", v.inspect(args.span())?),
+                args.span(),
+            )
+                .into())
+        }
+    };
+
+    let module = match args.default_arg(1, "module", Value::Null)? {
+        Value::String(s, _) => Some(s),
+        Value::Null => None,
+        v => {
+            return Err((
+                format!("$module: {} is not a string.", v.inspect(args.span())?),
+                args.span(),
+            )
+                .into())
+        }
+    };
+
+    Ok(Value::bool(if let Some(module_name) = module {
+        parser
+            .modules
+            .get(module_name.into(), args.span())?
+            .var_exists(name)
+    } else {
+        parser.global_scope.var_exists(name)
+    }))
 }
 
 pub(crate) fn mixin_exists(mut args: CallArgs, parser: &mut Parser<'_>) -> SassResult<Value> {

src/builtin/modules/mod.rs

@@ -65,6 +65,10 @@ impl Module {
         self.0.functions.get(&name).cloned()
     }
 
+    pub fn var_exists(&self, name: Identifier) -> bool {
+        self.0.var_exists(name)
+    }
+
     pub fn mixin_exists(&self, name: Identifier) -> bool {
         self.0.mixin_exists(name)
     }

tests/meta-module.rs

@@ -15,6 +15,11 @@ test!(
     "@use 'sass:meta';\n@use 'sass:math';\na {\n  color: inspect(meta.module-variables(math));\n}\n",
     "a {\n  color: (\"e\": 2.7182818285, \"pi\": 3.1415926536);\n}\n"
 );
+test!(
+    global_var_exists_module,
+    "@use 'sass:math';\na {\n  color: global-variable-exists(pi, $module: math);\n}\n",
+    "a {\n  color: true;\n}\n"
+);
 
 #[test]
 fn mixin_exists_module() {