add some comments of scope kind

Signed-off-by: he1pa <18012015693@163.com>

kclvm/sema/src/advanced_resolver/node.rs

@@ -1011,7 +1011,7 @@ impl<'ctx> AdvancedResolver<'ctx> {
         let schema_symbol = self.ctx.current_schema_symbol.take();
         let kind = match &schema_symbol {
             Some(_) => LocalSymbolScopeKind::SchemaConfig,
-            None => LocalSymbolScopeKind::Common,
+            None => LocalSymbolScopeKind::Value,
         };
 
         self.enter_local_scope(
@@ -1042,7 +1042,7 @@ impl<'ctx> AdvancedResolver<'ctx> {
                 &self.ctx.current_filename.as_ref().unwrap().clone(),
                 start,
                 end,
-                LocalSymbolScopeKind::Common,
+                LocalSymbolScopeKind::Value,
             );
 
             self.expr(&entry.node.value);

kclvm/sema/src/core/scope.rs

@@ -312,7 +312,7 @@ pub enum LocalSymbolScopeKind {
     Lambda,
     SchemaDef,
     SchemaConfig,
-    Common,
+    Value,
 }
 
 impl Scope for LocalSymbolScope {
@@ -384,7 +384,25 @@ impl Scope for LocalSymbolScope {
                 }
             }
         }
-
+        // In SchemaConfig, available definitions only contain keys of schema attr，i.e., `left` values in schema expr.
+        // but in child scope, i.e., right value in schema expr, available definitions contain all parent definitions.
+        // ```
+        // b = "bar"
+        // foo = Foo{
+        //   bar: b
+        // }
+        // ````
+        // and scope range is(use `#kind[]` to represent the range of the scope`)
+        // ```
+        // #Root[
+        // b = "bar"
+        // foo = Foo #SchemaConfig[{
+        //   bar: #Value[b]
+        // }]
+        // ]
+        // ````
+        // At position of `bar`, the scope kind is SchemaConfig, only get the definition of bar.
+        // At position of seconde `b`, the scope is the child scope of SchemaConfig, need to recursively find the definition of `b`` at a higher level
         if self.kind == LocalSymbolScopeKind::SchemaConfig && !recursive {
             return all_defs_map;
         } else {