Unified: Fix translation of wildcard patterns

unified/extractor/ast_types.yml

@@ -37,6 +37,7 @@ supertypes:
     - or_pattern
     - conditional_pattern
     - bulk_importing_pattern
+    - ignore_pattern
     - generic_type_expr
     - inferred_type_expr
   # An element of an `unresolved_operator_sequence`: either an operand (`expr`)
@@ -411,6 +412,9 @@ named:
   bulk_importing_pattern:
     modifier*: modifier
 
+  # A pattern that accepts any incoming value, usually written as an `_`.
+  ignore_pattern:
+
   # A simple unqualified name token
   identifier:
 

unified/extractor/src/languages/swift/swift.rs

@@ -206,9 +206,8 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
         // referenced identifier / operator symbol.
         rule!((declReferenceExpr baseName: @name) => (identifier #{name})),
         // A discard `_` used as an expression — e.g. the target of a discarding
-        // assignment `_ = x`. swift-syntax models it as a `discardAssignmentExpr`;
-        // the target AST represents it as a `name_node` over the `_` token.
-        rule!((discardAssignmentExpr wildcard: @@w) => (identifier #{w})),
+        // assignment `_ = x`. swift-syntax models it as a `discardAssignmentExpr`.
+        rule!((discardAssignmentExpr wildcard: @@w) => (ignore_pattern #{w})),
         // A generic specialization in expression position (`C<Foo>`,
         // `Array<Int>`) is represented by swift-syntax as a
         // `genericSpecializationExpr`. When used as a call target
@@ -560,7 +559,7 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
         // A wildcard *binding* pattern (`let _ = x`, `for _ in xs`). swift-syntax
         // models this as a `wildcardPattern`, distinct from the `_` match form
         // handled by the context-aware `discardAssignmentExpr` rule.
-        rule!((wildcardPattern) @@wildcard => (identifier #{wildcard})),
+        rule!((wildcardPattern) @@wildcard => (ignore_pattern #{wildcard})),
         // An expression pattern only establishes pattern context; its child
         // determines the concrete pattern shape.
         rule!((expressionPattern expression: @@e) => expr {

unified/extractor/tests/corpus/swift/control-flow/switch-with-labeled-case-pattern-arguments.output

@@ -159,7 +159,7 @@ top_level source="⟨body⟩"
                   argument:
                     argument source="⟨name_node⟩: ⟨value⟩"
                       name_node: identifier "threadRowId" source="threadRowId"
-                      value: identifier "_" source="_"
+                      value: ignore_pattern "_" source="_"
                     argument source="⟨value⟩"
                       value:
                         expr_pattern source="⟨modifier⟩ ⟨expr⟩"

unified/extractor/tests/corpus/swift/expressions/super-expression.output

@@ -171,7 +171,7 @@ top_level source="⟨body⟩"
                 block source="{\n    ⟨stmt⟩\n    ⟨stmt⟩\n  }"
                   stmt:
                     binary_expr source="⟨left⟩ ⟨operator⟩ ⟨right⟩"
-                      left: identifier "_" source="_"
+                      left: ignore_pattern "_" source="_"
                       operator: infix_operator "=" source="="
                       right:
                         member_access_expr source="⟨base⟩.⟨member_name_node⟩"

unified/extractor/tests/corpus/swift/operators/unresolved-operator-sequence-with-casts.output

@@ -109,7 +109,7 @@ top_level source="⟨body⟩"
               stmt:
                 unresolved_operator_sequence source="⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩"
                   element:
-                    identifier "_" source="_"
+                    ignore_pattern "_" source="_"
                     infix_operator "=" source="="
                     identifier "a" source="a"
                     infix_operator "as" source="as"
@@ -118,7 +118,7 @@ top_level source="⟨body⟩"
                     identifier "b" source="b"
                 unresolved_operator_sequence source="⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩"
                   element:
-                    identifier "_" source="_"
+                    ignore_pattern "_" source="_"
                     infix_operator "=" source="="
                     identifier "a" source="a"
                     infix_operator "is" source="is"

unified/extractor/tests/corpus/swift/operators/unresolved-operator-sequence.output

@@ -82,7 +82,7 @@ top_level source="⟨body⟩"
               stmt:
                 unresolved_operator_sequence source="⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩ ⟨element⟩"
                   element:
-                    identifier "_" source="_"
+                    ignore_pattern "_" source="_"
                     infix_operator "=" source="="
                     identifier "a" source="a"
                     infix_operator ".&" source=".&"

unified/ql/lib/codeql/unified/internal/Ast.qll

@@ -836,6 +836,12 @@ module Unified {
     }
   }
 
+  /** A class representing `ignore_pattern` tokens. */
+  class IgnorePattern extends @unified_token_ignore_pattern, F::Expr, F::Token {
+    /** Gets the name of the primary QL class for this element. */
+    final override string getAPrimaryQlClass() { result = "IgnorePattern" }
+  }
+
   /** A class representing `import_declaration` nodes. */
   class ImportDeclaration extends @unified_import_declaration, F::Stmt {
     /** Gets the name of the primary QL class for this element. */
@@ -1894,6 +1900,8 @@ module UnifiedFinal {
 
   final class IfExpr = F::IfExpr;
 
+  final class IgnorePattern = F::IgnorePattern;
+
   final class ImportDeclaration = F::ImportDeclaration;
 
   final class InferredTypeExpr = F::InferredTypeExpr;

unified/ql/lib/unified.dbscheme

@@ -435,7 +435,7 @@ unified_equality_type_constraint_def(
   int right: @unified_expr ref
 );
 
-@unified_expr = @unified_array_literal | @unified_binary_expr | @unified_block | @unified_break_expr | @unified_bulk_importing_pattern | @unified_call_expr | @unified_conditional_pattern | @unified_continue_expr | @unified_expr_pattern | @unified_function_expr | @unified_generic_type_expr | @unified_if_expr | @unified_key_value_pair | @unified_map_literal | @unified_member_access_expr | @unified_named_pattern | @unified_or_pattern | @unified_pattern_guard_expr | @unified_return_expr | @unified_string_interpolation_expr | @unified_switch_expr | @unified_throw_expr | @unified_token_boolean_literal | @unified_token_builtin_expr | @unified_token_empty_expr | @unified_token_float_literal | @unified_token_identifier | @unified_token_inferred_type_expr | @unified_token_int_literal | @unified_token_regex_literal | @unified_token_string_literal | @unified_token_super_expr | @unified_token_unsupported_node | @unified_try_expr | @unified_tuple_expr | @unified_type_cast_expr | @unified_type_test_expr | @unified_unary_expr | @unified_unresolved_operator_sequence
+@unified_expr = @unified_array_literal | @unified_binary_expr | @unified_block | @unified_break_expr | @unified_bulk_importing_pattern | @unified_call_expr | @unified_conditional_pattern | @unified_continue_expr | @unified_expr_pattern | @unified_function_expr | @unified_generic_type_expr | @unified_if_expr | @unified_key_value_pair | @unified_map_literal | @unified_member_access_expr | @unified_named_pattern | @unified_or_pattern | @unified_pattern_guard_expr | @unified_return_expr | @unified_string_interpolation_expr | @unified_switch_expr | @unified_throw_expr | @unified_token_boolean_literal | @unified_token_builtin_expr | @unified_token_empty_expr | @unified_token_float_literal | @unified_token_identifier | @unified_token_ignore_pattern | @unified_token_inferred_type_expr | @unified_token_int_literal | @unified_token_regex_literal | @unified_token_string_literal | @unified_token_super_expr | @unified_token_unsupported_node | @unified_try_expr | @unified_tuple_expr | @unified_type_cast_expr | @unified_type_test_expr | @unified_unary_expr | @unified_unresolved_operator_sequence
 
 @unified_expr_or_operator = @unified_expr | @unified_token_infix_operator
 
@@ -980,16 +980,17 @@ case @unified_token.kind of
 | 5 = @unified_token_fixity
 | 6 = @unified_token_float_literal
 | 7 = @unified_token_identifier
-| 8 = @unified_token_inferred_type_expr
-| 9 = @unified_token_infix_operator
-| 10 = @unified_token_int_literal
-| 11 = @unified_token_modifier
-| 12 = @unified_token_postfix_operator
-| 13 = @unified_token_prefix_operator
-| 14 = @unified_token_regex_literal
-| 15 = @unified_token_string_literal
-| 16 = @unified_token_super_expr
-| 17 = @unified_token_unsupported_node
+| 8 = @unified_token_ignore_pattern
+| 9 = @unified_token_inferred_type_expr
+| 10 = @unified_token_infix_operator
+| 11 = @unified_token_int_literal
+| 12 = @unified_token_modifier
+| 13 = @unified_token_postfix_operator
+| 14 = @unified_token_prefix_operator
+| 15 = @unified_token_regex_literal
+| 16 = @unified_token_string_literal
+| 17 = @unified_token_super_expr
+| 18 = @unified_token_unsupported_node
 ;