Validate the type params of an entry once

`ClassEntry#type_params` and `ModuleEntry#type_params` validated the
consistency of the type params across the declarations on every call,
renaming and comparing the param lists each time, and the definition
builder reads `type_params` of the same entries over and over while
resolving ancestors. Record a successful validation and skip it until
`<<` adds another declaration; a failed validation is not recorded and
raises again.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: claude

lib/rbs/environment/class_entry.rb

@@ -15,6 +15,7 @@ def initialize(name)
       def <<(context_decl)
         context_decls << context_decl
         @primary_decl = nil
+        @type_params_validated = nil
         self
       end
 
@@ -50,6 +51,10 @@ def type_params
       end
 
       def validate_type_params
+        # The entry only changes with `<<`, which resets the memo -- a failed
+        # validation is not recorded and raises again
+        return if @type_params_validated
+
         unless context_decls.empty?
           first_decl, *rest_decls = each_decl.to_a
           first_decl or raise
@@ -63,6 +68,8 @@ def validate_type_params
             end
           end
         end
+
+        @type_params_validated = true
       end
 
       def align_params(decl)

lib/rbs/environment/module_entry.rb

@@ -14,6 +14,7 @@ def initialize(name)
 
       def <<(context_decl)
         context_decls << context_decl
+        @type_params_validated = nil
         self
       end
 
@@ -72,6 +73,10 @@ def align_params(decl)
       end
 
       def validate_type_params
+        # The entry only changes with `<<`, which resets the memo -- a failed
+        # validation is not recorded and raises again
+        return if @type_params_validated
+
         unless context_decls.empty?
           first_decl, *rest_decls = each_decl.to_a
           first_decl or raise
@@ -85,6 +90,8 @@ def validate_type_params
             end
           end
         end
+
+        @type_params_validated = true
       end
     end
   end

sig/environment/class_entry.rbs

@@ -18,6 +18,8 @@ module RBS
 
       @primary_decl: declaration?
 
+      @type_params_validated: bool?
+
       def initialize: (TypeName) -> void
 
       def <<: (context_decl) -> self

sig/environment/module_entry.rbs

@@ -17,6 +17,8 @@ module RBS
 
       attr_reader context_decls: Array[context_decl]
 
+      @type_params_validated: bool?
+
       def initialize: (TypeName) -> void
 
       def <<: (context_decl) -> self