unified: Fix extraction bug

The special-cased labelExpr rules were problematic.
They are now coveered by a combination of more general rules.

Author: asgerf

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

@@ -533,6 +533,11 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
             =>
             (identifier #{name})
         ),
+        rule!(
+            (patternExpr pattern: @p)
+            =>
+            expr { p }
+        ),
         // A `let`/`var` value-binding pattern (`let x`) inside a case or `if case`
         // preserves the binding specifier around its inner pattern.
         rule!(
@@ -696,44 +701,11 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 tree!((call_expr callee: {callee} argument: {args}))
             }
         ),
-        // A call or enum-case pattern argument. Both use the shared `argument`
-        // shape, preserving the optional label as `name` and the child as `value`.
-        // The pattern-only shapes (`patternExpr`, `discardAssignmentExpr`) are
-        // matched first; they never occur as ordinary call arguments.
-        rule!(
-            (labeledExpr
-                label: _? @@lbl
-                expression: (functionCallExpr
-                    calledExpression: @constructor
-                    arguments: _* @elements) @@call)
-            =>
-            argument {
-                let value = tree_at!(
-                    ctx,
-                    call,
-                    (call_expr callee: {constructor} argument: {elements})
-                );
-                tree!((argument
-                    name_node: (identifier #{lbl})?
-                    value: {value}))
-            }
-        ),
-        rule!(
-            (labeledExpr label: _? @@lbl expression: (patternExpr pattern: @p))
-            =>
-            (argument name_node: (identifier #{lbl})? value: {p})
-        ),
-        rule!(
-            (labeledExpr label: _? @@lbl expression: (discardAssignmentExpr) @@wildcard)
-            =>
-            (argument name_node: (identifier #{lbl})? value: (identifier #{wildcard}))
-        ),
+        // A call or enum-case pattern argument.
         rule!(
             (labeledExpr label: _? @@lbl expression: @val)
             =>
-            argument {
-                tree!((argument name_node: (identifier #{lbl})? value: {val}))
-            }
+            (argument name_node: (identifier #{lbl})? value: {val})
         ),
         // Member access (`list.append`). The `declName` is itself a
         // `declReferenceExpr`; pull its `baseName` out as the member identifier.

unified/extractor/tests/corpus/swift/closures/nested-trailing-closure.output

@@ -58,8 +58,19 @@ top_level source="⟨body⟩"
           argument:
             argument source="⟨value⟩"
               value:
-                call_expr source="⟨callee⟩ { $0 * 2 }"
+                call_expr source="⟨callee⟩ ⟨argument⟩"
                   callee:
                     member_access_expr source="⟨base⟩.⟨member_name_node⟩"
                       base: identifier "xs" source="xs"
                       member_name_node: identifier "map" source="map"
+                  argument:
+                    argument source="⟨value⟩"
+                      value:
+                        function_expr source="{ ⟨body⟩ }"
+                          body:
+                            block source="⟨stmt⟩"
+                              stmt:
+                                binary_expr source="⟨left⟩ ⟨operator⟩ ⟨right⟩"
+                                  left: identifier "$0" source="$0"
+                                  operator: infix_operator "*" source="*"
+                                  right: int_literal "2" source="2"

unified/ql/test/query-tests/unusedentities/UnusedVariable.expected

@@ -1,2 +1,2 @@
 | test.swift:2:9:2:9 | a | Unused local variable 'a' |
-| test.swift:12:9:12:9 | a | Unused local variable 'a' |
+| test.swift:16:13:16:13 | b | Unused local variable 'b' |

unified/ql/test/query-tests/unusedentities/test.swift

@@ -10,9 +10,9 @@ func t2() -> Int {
         return "df"
     }
     // Note: This currently fails because the trailing closure is not extracted correctly
-    let a = 1 // $ SPURIOUS: Alert
+    let a = 1
     print(foo() { _ in
         print(a)
-        let b = 2 // $ MISSING: Alert[unified/unused-variable]
+        let b = 2 // $ Alert[unified/unused-variable]
     })
 }