Add parameter type inline annotation

config.yml

@@ -784,6 +784,20 @@ nodes:
       - name: type_name_location
         c_type: rbs_location_range
         optional: true
+  - name: RBS::AST::Ruby::Annotations::ParamTypeAnnotation
+    rust_name: ParamTypeAnnotationNode
+    fields:
+      - name: prefix_location
+        c_type: rbs_location_range
+      - name: name_location
+        c_type: rbs_location_range
+      - name: colon_location
+        c_type: rbs_location_range
+      - name: param_type
+        c_type: rbs_node
+      - name: comment_location
+        c_type: rbs_location_range
+        optional: true
 
 enums:
   attribute_visibility:
@@ -815,4 +829,4 @@ enums:
     symbols:
       - invariant
       - covariant
-      - contravariant
+      - contravariant

docs/inline.md

@@ -219,21 +219,60 @@ end
 
 #### Doc-style syntax
 
+The doc-style syntax allows annotating individual method parameters and the return type using `@rbs NAME: TYPE` comments.
+
+The `@rbs PARAM_NAME: T` syntax declares the type of a parameter:
+
+```ruby
+class Calculator
+  # @rbs x: Integer
+  # @rbs y: Integer
+  def add(x, y:)
+    x + y
+  end
+end
+```
+
+You can add a description after `--`:
+
+```ruby
+class Calculator
+  # @rbs x: Integer -- the first operand
+  # @rbs y: Integer -- the second operand
+  def add(x, y:)
+    x + y
+  end
+end
+```
+
 The `@rbs return: T` syntax declares the return type of a method:
 
 ```ruby
 class Calculator
-  # @rbs return: String
+  # @rbs return: String -- a human-readable representation
   def to_s
     "Calculator"
   end
 end
 ```
 
+Both can be combined:
+
+```ruby
+class Calculator
+  # @rbs x: Integer -- the first operand
+  # @rbs y: Integer -- the second operand
+  # @rbs return: Integer
+  def add(x, y:)
+    x + y
+  end
+end
+```
+
 ### Current Limitations
 
 - Class methods and singleton methods are not supported
-- Parameter types are not supported with doc-style syntax
+- Only positional and keyword parameters are supported. Splat parameters (`*x`, `**y`) and block parameter (`&block`) are not supported yet. 
 - Method visibility declaration is not supported yet
 
 ## Attributes

ext/rbs_extension/ast_translation.c

@@ -921,6 +921,23 @@ VALUE rbs_struct_to_ruby_value(rbs_translation_context_t ctx, rbs_node_t *instan
             &h
         );
     }
+    case RBS_AST_RUBY_ANNOTATIONS_PARAM_TYPE_ANNOTATION: {
+        rbs_ast_ruby_annotations_param_type_annotation_t *node = (rbs_ast_ruby_annotations_param_type_annotation_t *) instance;
+
+        VALUE h = rb_hash_new();
+        rb_hash_aset(h, ID2SYM(rb_intern("location")), rbs_location_range_to_ruby_location(ctx, node->base.location));
+        rb_hash_aset(h, ID2SYM(rb_intern("prefix_location")), rbs_location_range_to_ruby_location(ctx, node->prefix_location));
+        rb_hash_aset(h, ID2SYM(rb_intern("name_location")), rbs_location_range_to_ruby_location(ctx, node->name_location));
+        rb_hash_aset(h, ID2SYM(rb_intern("colon_location")), rbs_location_range_to_ruby_location(ctx, node->colon_location));
+        rb_hash_aset(h, ID2SYM(rb_intern("param_type")), rbs_struct_to_ruby_value(ctx, (rbs_node_t *) node->param_type));         // rbs_node
+        rb_hash_aset(h, ID2SYM(rb_intern("comment_location")), rbs_location_range_to_ruby_location(ctx, node->comment_location)); // optional
+
+        return CLASS_NEW_INSTANCE(
+            RBS_AST_Ruby_Annotations_ParamTypeAnnotation,
+            1,
+            &h
+        );
+    }
     case RBS_AST_RUBY_ANNOTATIONS_RETURN_TYPE_ANNOTATION: {
         rbs_ast_ruby_annotations_return_type_annotation_t *node = (rbs_ast_ruby_annotations_return_type_annotation_t *) instance;
 

ext/rbs_extension/class_constants.c

@@ -53,6 +53,7 @@ VALUE RBS_AST_Ruby_Annotations_InstanceVariableAnnotation;
 VALUE RBS_AST_Ruby_Annotations_MethodTypesAnnotation;
 VALUE RBS_AST_Ruby_Annotations_ModuleAliasAnnotation;
 VALUE RBS_AST_Ruby_Annotations_NodeTypeAssertion;
+VALUE RBS_AST_Ruby_Annotations_ParamTypeAnnotation;
 VALUE RBS_AST_Ruby_Annotations_ReturnTypeAnnotation;
 VALUE RBS_AST_Ruby_Annotations_SkipAnnotation;
 VALUE RBS_AST_Ruby_Annotations_TypeApplicationAnnotation;
@@ -142,6 +143,7 @@ void rbs__init_constants(void) {
     IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_MethodTypesAnnotation, RBS_AST_Ruby_Annotations, "MethodTypesAnnotation");
     IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_ModuleAliasAnnotation, RBS_AST_Ruby_Annotations, "ModuleAliasAnnotation");
     IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_NodeTypeAssertion, RBS_AST_Ruby_Annotations, "NodeTypeAssertion");
+    IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_ParamTypeAnnotation, RBS_AST_Ruby_Annotations, "ParamTypeAnnotation");
     IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_ReturnTypeAnnotation, RBS_AST_Ruby_Annotations, "ReturnTypeAnnotation");
     IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_SkipAnnotation, RBS_AST_Ruby_Annotations, "SkipAnnotation");
     IMPORT_CONSTANT(RBS_AST_Ruby_Annotations_TypeApplicationAnnotation, RBS_AST_Ruby_Annotations, "TypeApplicationAnnotation");

ext/rbs_extension/class_constants.h

@@ -61,6 +61,7 @@ extern VALUE RBS_AST_Ruby_Annotations_InstanceVariableAnnotation;
 extern VALUE RBS_AST_Ruby_Annotations_MethodTypesAnnotation;
 extern VALUE RBS_AST_Ruby_Annotations_ModuleAliasAnnotation;
 extern VALUE RBS_AST_Ruby_Annotations_NodeTypeAssertion;
+extern VALUE RBS_AST_Ruby_Annotations_ParamTypeAnnotation;
 extern VALUE RBS_AST_Ruby_Annotations_ReturnTypeAnnotation;
 extern VALUE RBS_AST_Ruby_Annotations_SkipAnnotation;
 extern VALUE RBS_AST_Ruby_Annotations_TypeApplicationAnnotation;

include/rbs/ast.h

@@ -96,41 +96,42 @@ enum rbs_node_type {
     RBS_AST_RUBY_ANNOTATIONS_METHOD_TYPES_ANNOTATION = 35,
     RBS_AST_RUBY_ANNOTATIONS_MODULE_ALIAS_ANNOTATION = 36,
     RBS_AST_RUBY_ANNOTATIONS_NODE_TYPE_ASSERTION = 37,
-    RBS_AST_RUBY_ANNOTATIONS_RETURN_TYPE_ANNOTATION = 38,
-    RBS_AST_RUBY_ANNOTATIONS_SKIP_ANNOTATION = 39,
-    RBS_AST_RUBY_ANNOTATIONS_TYPE_APPLICATION_ANNOTATION = 40,
-    RBS_AST_STRING = 41,
-    RBS_AST_TYPE_PARAM = 42,
-    RBS_METHOD_TYPE = 43,
-    RBS_NAMESPACE = 44,
-    RBS_SIGNATURE = 45,
-    RBS_TYPE_NAME = 46,
-    RBS_TYPES_ALIAS = 47,
-    RBS_TYPES_BASES_ANY = 48,
-    RBS_TYPES_BASES_BOOL = 49,
-    RBS_TYPES_BASES_BOTTOM = 50,
-    RBS_TYPES_BASES_CLASS = 51,
-    RBS_TYPES_BASES_INSTANCE = 52,
-    RBS_TYPES_BASES_NIL = 53,
-    RBS_TYPES_BASES_SELF = 54,
-    RBS_TYPES_BASES_TOP = 55,
-    RBS_TYPES_BASES_VOID = 56,
-    RBS_TYPES_BLOCK = 57,
-    RBS_TYPES_CLASS_INSTANCE = 58,
-    RBS_TYPES_CLASS_SINGLETON = 59,
-    RBS_TYPES_FUNCTION = 60,
-    RBS_TYPES_FUNCTION_PARAM = 61,
-    RBS_TYPES_INTERFACE = 62,
-    RBS_TYPES_INTERSECTION = 63,
-    RBS_TYPES_LITERAL = 64,
-    RBS_TYPES_OPTIONAL = 65,
-    RBS_TYPES_PROC = 66,
-    RBS_TYPES_RECORD = 67,
-    RBS_TYPES_RECORD_FIELD_TYPE = 68,
-    RBS_TYPES_TUPLE = 69,
-    RBS_TYPES_UNION = 70,
-    RBS_TYPES_UNTYPED_FUNCTION = 71,
-    RBS_TYPES_VARIABLE = 72,
+    RBS_AST_RUBY_ANNOTATIONS_PARAM_TYPE_ANNOTATION = 38,
+    RBS_AST_RUBY_ANNOTATIONS_RETURN_TYPE_ANNOTATION = 39,
+    RBS_AST_RUBY_ANNOTATIONS_SKIP_ANNOTATION = 40,
+    RBS_AST_RUBY_ANNOTATIONS_TYPE_APPLICATION_ANNOTATION = 41,
+    RBS_AST_STRING = 42,
+    RBS_AST_TYPE_PARAM = 43,
+    RBS_METHOD_TYPE = 44,
+    RBS_NAMESPACE = 45,
+    RBS_SIGNATURE = 46,
+    RBS_TYPE_NAME = 47,
+    RBS_TYPES_ALIAS = 48,
+    RBS_TYPES_BASES_ANY = 49,
+    RBS_TYPES_BASES_BOOL = 50,
+    RBS_TYPES_BASES_BOTTOM = 51,
+    RBS_TYPES_BASES_CLASS = 52,
+    RBS_TYPES_BASES_INSTANCE = 53,
+    RBS_TYPES_BASES_NIL = 54,
+    RBS_TYPES_BASES_SELF = 55,
+    RBS_TYPES_BASES_TOP = 56,
+    RBS_TYPES_BASES_VOID = 57,
+    RBS_TYPES_BLOCK = 58,
+    RBS_TYPES_CLASS_INSTANCE = 59,
+    RBS_TYPES_CLASS_SINGLETON = 60,
+    RBS_TYPES_FUNCTION = 61,
+    RBS_TYPES_FUNCTION_PARAM = 62,
+    RBS_TYPES_INTERFACE = 63,
+    RBS_TYPES_INTERSECTION = 64,
+    RBS_TYPES_LITERAL = 65,
+    RBS_TYPES_OPTIONAL = 66,
+    RBS_TYPES_PROC = 67,
+    RBS_TYPES_RECORD = 68,
+    RBS_TYPES_RECORD_FIELD_TYPE = 69,
+    RBS_TYPES_TUPLE = 70,
+    RBS_TYPES_UNION = 71,
+    RBS_TYPES_UNTYPED_FUNCTION = 72,
+    RBS_TYPES_VARIABLE = 73,
     RBS_AST_SYMBOL,
 };
 
@@ -612,6 +613,16 @@ typedef struct rbs_ast_ruby_annotations_node_type_assertion {
     struct rbs_node *type;
 } rbs_ast_ruby_annotations_node_type_assertion_t;
 
+typedef struct rbs_ast_ruby_annotations_param_type_annotation {
+    rbs_node_t base;
+
+    rbs_location_range prefix_location;
+    rbs_location_range name_location;
+    rbs_location_range colon_location;
+    struct rbs_node *param_type;
+    rbs_location_range comment_location; /* Optional */
+} rbs_ast_ruby_annotations_param_type_annotation_t;
+
 typedef struct rbs_ast_ruby_annotations_return_type_annotation {
     rbs_node_t base;
 
@@ -881,6 +892,7 @@ typedef union rbs_ast_ruby_annotations {
     rbs_ast_ruby_annotations_node_type_assertion_t node_type_assertion;
     rbs_ast_ruby_annotations_return_type_annotation_t return_type_annotation;
     rbs_ast_ruby_annotations_skip_annotation_t skip_annotation;
+    rbs_ast_ruby_annotations_param_type_annotation_t param_type_annotation;
 } rbs_ast_ruby_annotations_t;
 
 /// `rbs_ast_symbol_t` models user-defined identifiers like class names, method names, etc.
@@ -929,6 +941,7 @@ rbs_ast_ruby_annotations_instance_variable_annotation_t *rbs_ast_ruby_annotation
 rbs_ast_ruby_annotations_method_types_annotation_t *rbs_ast_ruby_annotations_method_types_annotation_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_node_list_t *overloads, rbs_location_range_list_t *vertical_bar_locations, rbs_location_range dot3_location);
 rbs_ast_ruby_annotations_module_alias_annotation_t *rbs_ast_ruby_annotations_module_alias_annotation_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_location_range keyword_location, rbs_type_name_t *type_name, rbs_location_range type_name_location);
 rbs_ast_ruby_annotations_node_type_assertion_t *rbs_ast_ruby_annotations_node_type_assertion_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_node_t *type);
+rbs_ast_ruby_annotations_param_type_annotation_t *rbs_ast_ruby_annotations_param_type_annotation_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_location_range name_location, rbs_location_range colon_location, rbs_node_t *param_type, rbs_location_range comment_location);
 rbs_ast_ruby_annotations_return_type_annotation_t *rbs_ast_ruby_annotations_return_type_annotation_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_location_range return_location, rbs_location_range colon_location, rbs_node_t *return_type, rbs_location_range comment_location);
 rbs_ast_ruby_annotations_skip_annotation_t *rbs_ast_ruby_annotations_skip_annotation_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_location_range skip_location, rbs_location_range comment_location);
 rbs_ast_ruby_annotations_type_application_annotation_t *rbs_ast_ruby_annotations_type_application_annotation_new(rbs_allocator_t *allocator, rbs_location_range location, rbs_location_range prefix_location, rbs_node_list_t *type_args, rbs_location_range close_bracket_location, rbs_location_range_list_t *comma_locations);

lib/rbs/ast/ruby/annotations.rb

@@ -252,6 +252,29 @@ def type_fingerprint
             ]
           end
         end
+
+        class ParamTypeAnnotation < Base
+          attr_reader :name_location, :colon_location, :param_type, :comment_location
+
+          def initialize(location:, prefix_location:, name_location:, colon_location:, param_type:, comment_location:)
+            super(location, prefix_location)
+            @name_location = name_location
+            @colon_location = colon_location
+            @param_type = param_type
+            @comment_location = comment_location
+          end
+
+          def map_type_name(&block)
+            self.class.new(
+              location:,
+              prefix_location:,
+              name_location: name_location,
+              colon_location: colon_location,
+              param_type: param_type.map_type_name { yield _1 },
+              comment_location: comment_location
+            ) #: self
+          end
+        end
       end
     end
   end