Don't resolve FieldFormalParameter field if not in constructor.

pkg/analyzer/lib/src/generated/error_verifier.dart

Index: pkg/analyzer/lib/src/generated/error_verifier.dart
diff --git a/pkg/analyzer/lib/src/generated/error_verifier.dart b/pkg/analyzer/lib/src/generated/error_verifier.dart
index 742a0a168d9145f5df570c80d1f73ea4375f5e35..52cf7dadc85eb6f3750c1cb52b05a79edad54f56 100644
--- a/pkg/analyzer/lib/src/generated/error_verifier.dart
+++ b/pkg/analyzer/lib/src/generated/error_verifier.dart
@@ -5904,6 +5904,11 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
   }
 
   void _checkForValidField(FieldFormalParameter parameter) {
+    AstNode parent2 = parameter.parent?.parent;
+    if (parent2 is! ConstructorDeclaration &&
+        parent2?.parent is! ConstructorDeclaration) {
+      return;
+    }
     ParameterElement element = parameter.element;
     if (element is FieldFormalParameterElement) {
       FieldElement fieldElement = element.field;