feat: BACK-8055 Detect unused definitions

src/erc7730/lint/lint.py

@@ -10,6 +10,7 @@
 from erc7730.lint.lint_base import MultiLinter
 from erc7730.lint.lint_transaction_type_classifier import ClassifyTransactionTypeLinter
 from erc7730.lint.lint_validate_abi import ValidateABILinter
+from erc7730.lint.lint_validate_definitions import DefinitionLinter
 from erc7730.lint.lint_validate_display_fields import ValidateDisplayFieldsLinter
 from erc7730.model.input.descriptor import InputERC7730Descriptor
 
@@ -42,11 +43,7 @@ def lint_all(paths: list[Path], out: OutputAdder) -> None:
     :return: output errors
     """
     linter = MultiLinter(
-        [
-            ValidateABILinter(),
-            ValidateDisplayFieldsLinter(),
-            ClassifyTransactionTypeLinter(),
-        ]
+        [ValidateABILinter(), ValidateDisplayFieldsLinter(), ClassifyTransactionTypeLinter(), DefinitionLinter()]
     )
 
     for path in paths:

src/erc7730/lint/lint_validate_definitions.py

@@ -0,0 +1,27 @@
+from typing import final, override
+
+from erc7730.common.output import OutputAdder
+from erc7730.lint import ERC7730Linter
+from erc7730.model.resolved.context import ResolvedEIP712Context
+from erc7730.model.resolved.descriptor import ResolvedERC7730Descriptor
+
+
+@final
+class DefinitionLinter(ERC7730Linter):
+    """Check that parameters under definitions are used in formats section"""
+
+    @override
+    def lint(self, descriptor: ResolvedERC7730Descriptor, out: OutputAdder) -> None:
+        if isinstance(descriptor.context, ResolvedEIP712Context) and descriptor.display.definitions is not None:
+            for name, _ in descriptor.display.definitions.items():
+                found = False
+                for _, format in descriptor.display.formats.items():
+                    if found is False:
+                        for field in format.fields:
+                            if field.path == name:
+                                found = True
+                if found is False:
+                    out.error(
+                        title="Unused field definition",
+                        message=f"Field {name} is not used in descriptor formats.",
+                    )