Allow empty statements of declarations in gnatprep

All runtime files and all the code from Deep Blue Capital are now
parsed without errors.

grammar.js

@@ -2215,16 +2215,16 @@ module.exports = grammar({
          reservedWord('#if'),
          field('condition', $.expression),
          reservedWord('then'),
-         $.non_empty_declarative_part,
+         repeat($._declarative_item_pragma),
          repeat(seq(
             reservedWord('#elsif'),
             field('condition', $.expression),
             reservedWord('then'),
-            $.non_empty_declarative_part,
+            repeat($._declarative_item_pragma),
          )),
          optional(seq(
             reservedWord('#else'),
-            $.non_empty_declarative_part,
+            repeat($._declarative_item_pragma),
          )),
          reservedWord('#end'),
          reservedWord('if'),
@@ -2234,16 +2234,16 @@ module.exports = grammar({
          reservedWord('#if'),
          field('condition', $.expression),
          reservedWord('then'),
-         field('statements', $._sequence_of_statements),
+         repeat($._statement),  // can be empty
          repeat(seq(
             reservedWord('#elsif'),
             field('condition', $.expression),
             reservedWord('then'),
-            field('statements', $._sequence_of_statements),
+            repeat($._statement),  // can be empty
          )),
          optional(seq(
             reservedWord('#else'),
-            field('else_statements', $._sequence_of_statements),
+            repeat($._statement),  // can be empty
          )),
          reservedWord('#end'),
          reservedWord('if'),

src/grammar.json

@@ -13820,8 +13820,11 @@
           "value": "then"
         },
         {
+          "type": "REPEAT",
+          "content": {
             "type": "SYMBOL",
-          "name": "non_empty_declarative_part"
+            "name": "_declarative_item_pragma"
+          }
         },
         {
           "type": "REPEAT",
@@ -13869,8 +13872,11 @@
                 "value": "then"
               },
               {
+                "type": "REPEAT",
+                "content": {
                   "type": "SYMBOL",
-                "name": "non_empty_declarative_part"
+                  "name": "_declarative_item_pragma"
+                }
               }
             ]
           }
@@ -13898,8 +13904,11 @@
                   "value": "#else"
                 },
                 {
+                  "type": "REPEAT",
+                  "content": {
                     "type": "SYMBOL",
-                  "name": "non_empty_declarative_part"
+                    "name": "_declarative_item_pragma"
+                  }
                 }
               ]
             },
@@ -13990,11 +13999,10 @@
           "value": "then"
         },
         {
-          "type": "FIELD",
+          "type": "REPEAT",
-          "name": "statements",
           "content": {
             "type": "SYMBOL",
-            "name": "_sequence_of_statements"
+            "name": "_statement"
           }
         },
         {
@@ -14043,11 +14051,10 @@
                 "value": "then"
               },
               {
-                "type": "FIELD",
+                "type": "REPEAT",
-                "name": "statements",
                 "content": {
                   "type": "SYMBOL",
-                  "name": "_sequence_of_statements"
+                  "name": "_statement"
                 }
               }
             ]
@@ -14076,11 +14083,10 @@
                   "value": "#else"
                 },
                 {
-                  "type": "FIELD",
+                  "type": "REPEAT",
-                  "name": "else_statements",
                   "content": {
                     "type": "SYMBOL",
-                    "name": "_sequence_of_statements"
+                    "name": "_statement"
                   }
                 }
               ]

src/node-types.json

@@ -6105,10 +6105,134 @@
     },
     "children": {
       "multiple": true,
-      "required": true,
+      "required": false,
       "types": [
         {
-          "type": "non_empty_declarative_part",
+          "type": "at_clause",
+          "named": true
+        },
+        {
+          "type": "attribute_definition_clause",
+          "named": true
+        },
+        {
+          "type": "body_stub",
+          "named": true
+        },
+        {
+          "type": "enumeration_representation_clause",
+          "named": true
+        },
+        {
+          "type": "exception_declaration",
+          "named": true
+        },
+        {
+          "type": "exception_renaming_declaration",
+          "named": true
+        },
+        {
+          "type": "expression_function_declaration",
+          "named": true
+        },
+        {
+          "type": "full_type_declaration",
+          "named": true
+        },
+        {
+          "type": "generic_instantiation",
+          "named": true
+        },
+        {
+          "type": "generic_package_declaration",
+          "named": true
+        },
+        {
+          "type": "generic_renaming_declaration",
+          "named": true
+        },
+        {
+          "type": "generic_subprogram_declaration",
+          "named": true
+        },
+        {
+          "type": "gnatprep_declarative_if_statement",
+          "named": true
+        },
+        {
+          "type": "incomplete_type_declaration",
+          "named": true
+        },
+        {
+          "type": "null_procedure_declaration",
+          "named": true
+        },
+        {
+          "type": "number_declaration",
+          "named": true
+        },
+        {
+          "type": "object_declaration",
+          "named": true
+        },
+        {
+          "type": "object_renaming_declaration",
+          "named": true
+        },
+        {
+          "type": "package_body",
+          "named": true
+        },
+        {
+          "type": "package_renaming_declaration",
+          "named": true
+        },
+        {
+          "type": "package_specification",
+          "named": true
+        },
+        {
+          "type": "pragma_g",
+          "named": true
+        },
+        {
+          "type": "private_extension_declaration",
+          "named": true
+        },
+        {
+          "type": "private_type_declaration",
+          "named": true
+        },
+        {
+          "type": "protected_body",
+          "named": true
+        },
+        {
+          "type": "record_representation_clause",
+          "named": true
+        },
+        {
+          "type": "subprogram_body",
+          "named": true
+        },
+        {
+          "type": "subprogram_declaration",
+          "named": true
+        },
+        {
+          "type": "subprogram_renaming_declaration",
+          "named": true
+        },
+        {
+          "type": "subtype_declaration",
+          "named": true
+        },
+        {
+          "type": "task_body",
+          "named": true
+        },
+        {
+          "type": "use_clause",
           "named": true
         }
       ]
@@ -6127,8 +6251,9 @@
             "named": true
           }
         ]
+      }
     },
-      "else_statements": {
+    "children": {
       "multiple": true,
       "required": false,
       "types": [
@@ -6229,109 +6354,6 @@
           "named": true
         }
       ]
-      },
-      "statements": {
-        "multiple": true,
-        "required": true,
-        "types": [
-          {
-            "type": "abort_statement",
-            "named": true
-          },
-          {
-            "type": "accept_statement",
-            "named": true
-          },
-          {
-            "type": "assignment_statement",
-            "named": true
-          },
-          {
-            "type": "asynchronous_select",
-            "named": true
-          },
-          {
-            "type": "block_statement",
-            "named": true
-          },
-          {
-            "type": "case_statement",
-            "named": true
-          },
-          {
-            "type": "conditional_entry_call",
-            "named": true
-          },
-          {
-            "type": "delay_relative_statement",
-            "named": true
-          },
-          {
-            "type": "delay_until_statement",
-            "named": true
-          },
-          {
-            "type": "exit_statement",
-            "named": true
-          },
-          {
-            "type": "extended_return_statement",
-            "named": true
-          },
-          {
-            "type": "gnatprep_if_statement",
-            "named": true
-          },
-          {
-            "type": "goto_statement",
-            "named": true
-          },
-          {
-            "type": "if_statement",
-            "named": true
-          },
-          {
-            "type": "label",
-            "named": true
-          },
-          {
-            "type": "loop_statement",
-            "named": true
-          },
-          {
-            "type": "null_statement",
-            "named": true
-          },
-          {
-            "type": "pragma_g",
-            "named": true
-          },
-          {
-            "type": "procedure_call_statement",
-            "named": true
-          },
-          {
-            "type": "raise_statement",
-            "named": true
-          },
-          {
-            "type": "requeue_statement",
-            "named": true
-          },
-          {
-            "type": "selective_accept",
-            "named": true
-          },
-          {
-            "type": "simple_return_statement",
-            "named": true
-          },
-          {
-            "type": "timed_entry_call",
-            "named": true
-          }
-        ]
-      }
     }
   },
   {

test/corpus/preprocessor.txt

@@ -23,13 +23,12 @@ end;
             (term
               (factor_not
                 (identifier))))
-          (non_empty_declarative_part
           (pragma_g
             (identifier)
             (pragma_argument_association
               (expression
                 (term
-                    (identifier))))))))
+                  (identifier)))))))
       (handled_sequence_of_statements
         (null_statement)))))
 
@@ -53,3 +52,32 @@ end;
         (expression
           (term
             (gnatprep_identifier)))))))
+
+================================================================================
+Preprocess empty (GNAT)
+================================================================================
+
+procedure P is
+   #if not CHECKING_MODE then
+      --  pragma Suppress (Access_Checks);
+   #end if;
+begin
+   null;
+end;
+
+--------------------------------------------------------------------------------
+
+(compilation
+  (compilation_unit
+    (subprogram_body
+      (procedure_specification
+        (identifier))
+      (non_empty_declarative_part
+        (gnatprep_declarative_if_statement
+          (expression
+            (term
+              (factor_not
+                (identifier))))
+          (comment)))
+      (handled_sequence_of_statements
+        (null_statement)))))