feat(lint): implement useUnifiedTypeSignature rule (#6320)

Co-authored-by: Emanuele Stoppa <[email protected]>

Author: mdevils

.changeset/some-coats-fail.md

@@ -0,0 +1,42 @@
+---
+"@biomejs/biome": patch
+---
+
+Added the new nursery rule [`useUnifiedTypeSignature`](https://biomejs.dev/linter/rules/use-unified-type-signature), which disallows overload signatures that can be unified into a single signature.
+
+Overload signatures that can be merged into a single signature are redundant and should be avoided. This rule helps simplify function signatures by combining overloads by making parameters optional and/or using type unions.
+
+**Example (Invalid): Overload signatures that can be unified:**
+
+```ts
+function f(a: number): void;
+function f(a: string): void;
+```
+
+```ts
+interface I {
+    a(): void;
+    a(x: number): void;
+}
+```
+
+**Example (Valid): Unified signatures:**
+
+```ts
+function f(a: number | string): void {}
+```
+
+```ts
+interface I {
+    a(x?: number): void;
+}
+```
+
+**Example (Valid): Different return types cannot be merged:**
+
+```ts
+interface I {
+    f(): void;
+    f(x: number): number;
+}
+```

crates/biome_cli/src/execute/migrate/eslint_any_rule_to_biome.rs

@@ -214,6 +214,7 @@ define_categories! {
     "lint/nursery/useSortedClasses": "https://biomejs.dev/linter/rules/use-sorted-classes",
     "lint/nursery/useSortedProperties": "https://biomejs.dev/linter/rules/use-sorted-properties",
     "lint/nursery/useSymbolDescription": "https://biomejs.dev/linter/rules/use-symbol-description",
+    "lint/nursery/useUnifiedTypeSignature": "https://biomejs.dev/linter/rules/use-unified-type-signature",
     "lint/nursery/useUniqueElementIds": "https://biomejs.dev/linter/rules/use-unique-element-ids",
     "lint/performance/noAccumulatingSpread": "https://biomejs.dev/linter/rules/no-accumulating-spread",
     "lint/performance/noBarrelFile": "https://biomejs.dev/linter/rules/no-barrel-file",

crates/biome_configuration/src/analyzer/linter/rules.rs

@@ -43,5 +43,6 @@ pub mod use_readonly_class_properties;
 pub mod use_single_js_doc_asterisk;
 pub mod use_sorted_classes;
 pub mod use_symbol_description;
+pub mod use_unified_type_signature;
 pub mod use_unique_element_ids;
-declare_lint_group! { pub Nursery { name : "nursery" , rules : [self :: no_await_in_loop :: NoAwaitInLoop , self :: no_bitwise_operators :: NoBitwiseOperators , self :: no_constant_binary_expression :: NoConstantBinaryExpression , self :: no_destructured_props :: NoDestructuredProps , self :: no_excessive_lines_per_function :: NoExcessiveLinesPerFunction , self :: no_floating_promises :: NoFloatingPromises , self :: no_global_dirname_filename :: NoGlobalDirnameFilename , self :: no_import_cycles :: NoImportCycles , self :: no_nested_component_definitions :: NoNestedComponentDefinitions , self :: no_noninteractive_element_interactions :: NoNoninteractiveElementInteractions , self :: no_process_global :: NoProcessGlobal , self :: no_react_prop_assign :: NoReactPropAssign , self :: no_restricted_elements :: NoRestrictedElements , self :: no_secrets :: NoSecrets , self :: no_shadow :: NoShadow , self :: no_ts_ignore :: NoTsIgnore , self :: no_unassigned_variables :: NoUnassignedVariables , self :: no_unresolved_imports :: NoUnresolvedImports , self :: no_unwanted_polyfillio :: NoUnwantedPolyfillio , self :: no_useless_backref_in_regex :: NoUselessBackrefInRegex , self :: no_useless_escape_in_string :: NoUselessEscapeInString , self :: no_useless_undefined :: NoUselessUndefined , self :: use_adjacent_getter_setter :: UseAdjacentGetterSetter , self :: use_consistent_object_definition :: UseConsistentObjectDefinition , self :: use_consistent_response :: UseConsistentResponse , self :: use_exhaustive_switch_cases :: UseExhaustiveSwitchCases , self :: use_explicit_type :: UseExplicitType , self :: use_exports_last :: UseExportsLast , self :: use_for_component :: UseForComponent , self :: use_google_font_preconnect :: UseGoogleFontPreconnect , self :: use_index_of :: UseIndexOf , self :: use_iterable_callback_return :: UseIterableCallbackReturn , self :: use_json_import_attribute :: UseJsonImportAttribute , self :: use_numeric_separators :: UseNumericSeparators , self :: use_object_spread :: UseObjectSpread , self :: use_parse_int_radix :: UseParseIntRadix , self :: use_readonly_class_properties :: UseReadonlyClassProperties , self :: use_single_js_doc_asterisk :: UseSingleJsDocAsterisk , self :: use_sorted_classes :: UseSortedClasses , self :: use_symbol_description :: UseSymbolDescription , self :: use_unique_element_ids :: UseUniqueElementIds ,] } }
+declare_lint_group! { pub Nursery { name : "nursery" , rules : [self :: no_await_in_loop :: NoAwaitInLoop , self :: no_bitwise_operators :: NoBitwiseOperators , self :: no_constant_binary_expression :: NoConstantBinaryExpression , self :: no_destructured_props :: NoDestructuredProps , self :: no_excessive_lines_per_function :: NoExcessiveLinesPerFunction , self :: no_floating_promises :: NoFloatingPromises , self :: no_global_dirname_filename :: NoGlobalDirnameFilename , self :: no_import_cycles :: NoImportCycles , self :: no_nested_component_definitions :: NoNestedComponentDefinitions , self :: no_noninteractive_element_interactions :: NoNoninteractiveElementInteractions , self :: no_process_global :: NoProcessGlobal , self :: no_react_prop_assign :: NoReactPropAssign , self :: no_restricted_elements :: NoRestrictedElements , self :: no_secrets :: NoSecrets , self :: no_shadow :: NoShadow , self :: no_ts_ignore :: NoTsIgnore , self :: no_unassigned_variables :: NoUnassignedVariables , self :: no_unresolved_imports :: NoUnresolvedImports , self :: no_unwanted_polyfillio :: NoUnwantedPolyfillio , self :: no_useless_backref_in_regex :: NoUselessBackrefInRegex , self :: no_useless_escape_in_string :: NoUselessEscapeInString , self :: no_useless_undefined :: NoUselessUndefined , self :: use_adjacent_getter_setter :: UseAdjacentGetterSetter , self :: use_consistent_object_definition :: UseConsistentObjectDefinition , self :: use_consistent_response :: UseConsistentResponse , self :: use_exhaustive_switch_cases :: UseExhaustiveSwitchCases , self :: use_explicit_type :: UseExplicitType , self :: use_exports_last :: UseExportsLast , self :: use_for_component :: UseForComponent , self :: use_google_font_preconnect :: UseGoogleFontPreconnect , self :: use_index_of :: UseIndexOf , self :: use_iterable_callback_return :: UseIterableCallbackReturn , self :: use_json_import_attribute :: UseJsonImportAttribute , self :: use_numeric_separators :: UseNumericSeparators , self :: use_object_spread :: UseObjectSpread , self :: use_parse_int_radix :: UseParseIntRadix , self :: use_readonly_class_properties :: UseReadonlyClassProperties , self :: use_single_js_doc_asterisk :: UseSingleJsDocAsterisk , self :: use_sorted_classes :: UseSortedClasses , self :: use_symbol_description :: UseSymbolDescription , self :: use_unified_type_signature :: UseUnifiedTypeSignature , self :: use_unique_element_ids :: UseUniqueElementIds ,] } }