Rename members when they collide with return/parameter type names (#265)

Web IDL allows members to have the same name as their
return or parameter types. Dart does not, and therefore,
we have to rename them. Cleans up some existing code and
makes renaming consistent by always adding an underscore
if needed.

Author: srujzs

tool/generator/translator.dart

@@ -297,15 +297,21 @@ class _Parameter {
 }
 
 sealed class _Property {
-  final _MemberName name;
+  late final _MemberName name;
   final _RawType type;
   final MdnProperty? mdnProperty;
 
   // TODO(srujzs): Remove ignore after
   // https://github.com/dart-lang/sdk/issues/55720 is resolved.
   // ignore: unused_element
-  _Property(this.name, idl.IDLType idlType, [this.mdnProperty])
-      : type = _getRawType(idlType);
+  _Property(_MemberName name, idl.IDLType idlType, [this.mdnProperty])
+      : type = _getRawType(idlType) {
+    // Rename the property if there's a collision with the type name.
+    final dartName = name.name;
+    final jsName = name.jsOverride.isEmpty ? dartName : name.jsOverride;
+    this.name =
+        dartName == type.type ? _MemberName('${dartName}_', jsName) : name;
+  }
 }
 
 class _Attribute extends _Property {
@@ -357,22 +363,47 @@ abstract class _OverridableMember {
 }
 
 class _OverridableOperation extends _OverridableMember {
-  _MemberName name;
+  bool _finalized = false;
+  _MemberName _name;
+
   final bool isStatic;
   final _RawType returnType;
   final MdnProperty? mdnProperty;
+  late final _MemberName name = _generateName();
 
-  _OverridableOperation._(this.name, this.isStatic, this.returnType,
+  _OverridableOperation._(this._name, this.isStatic, this.returnType,
       this.mdnProperty, super.parameters);
 
   factory _OverridableOperation(idl.Operation operation, _MemberName name,
           MdnProperty? mdnProperty) =>
       _OverridableOperation._(name, operation.special == 'static',
           _getRawType(operation.idlType), mdnProperty, operation.arguments);
 
+  _MemberName _generateName() {
+    // The name is determined after all updates are done, so finalize the
+    // operation.
+    _finalized = true;
+    // Rename the member if the name collides with a return or parameter type.
+    final dartName = _name.name;
+    if (dartName == returnType.type ||
+        parameters.any((parameter) => dartName == parameter.type.type)) {
+      underscoreName();
+    }
+    return _name;
+  }
+
+  void underscoreName() {
+    final jsName = _name.jsOverride.isEmpty ? _name.name : _name.jsOverride;
+    _name = _MemberName('${_name.name}_', jsName);
+  }
+
   void update(idl.Operation that) {
-    final jsOverride = name.jsOverride;
-    final thisName = jsOverride.isNotEmpty ? jsOverride : name.name;
+    assert(
+        !_finalized,
+        'Call to _OverridableOperation.update was made after the operation was '
+        'finalized.');
+    final jsOverride = _name.jsOverride;
+    final thisName = jsOverride.isNotEmpty ? jsOverride : _name.name;
     assert(thisName == that.name && isStatic == (that.special == 'static'));
     returnType.update(that.idlType);
     _processParameters(that.arguments);
@@ -462,28 +493,23 @@ class _PartialInterfacelike {
           final isStatic = operation.special == 'static';
           if (!_shouldGenerateMember(operationName, isStatic: isStatic)) break;
           final docs = mdnInterface?.propertyFor(operationName);
+          // Static member may have the same name as instance members in the
+          // IDL, but not in Dart. Rename the static member if so.
           if (isStatic) {
             if (staticOperations.containsKey(operationName)) {
               staticOperations[operationName]!.update(operation);
             } else {
-              final _MemberName memberName;
+              staticOperations[operationName] = _OverridableOperation(
+                  operation, _MemberName(operationName), docs);
               if (operations.containsKey(operationName)) {
-                memberName = _MemberName('${operationName}_', operationName);
-              } else {
-                memberName = _MemberName(operationName);
+                staticOperations[operationName]!.underscoreName();
               }
-              staticOperations[operationName] =
-                  _OverridableOperation(operation, memberName, docs);
             }
           } else {
             if (operations.containsKey(operationName)) {
               operations[operationName]!.update(operation);
             } else {
-              final staticOperation = staticOperations[operationName];
-              if (staticOperation != null) {
-                staticOperation.name =
-                    _MemberName('${operationName}_', operationName);
-              }
+              staticOperations[operationName]?.underscoreName();
               operations[operationName] = _OverridableOperation(
                   operation, _MemberName(operationName), docs);
             }