| 44 | |
| 45 | |
| 46 | class NewTypeAnalyzer: |
| 47 | def __init__( |
| 48 | self, options: Options, api: SemanticAnalyzerInterface, msg: MessageBuilder |
| 49 | ) -> None: |
| 50 | self.options = options |
| 51 | self.api = api |
| 52 | self.msg = msg |
| 53 | |
| 54 | def process_newtype_declaration(self, s: AssignmentStmt) -> bool: |
| 55 | """Check if s declares a NewType; if yes, store it in symbol table. |
| 56 | |
| 57 | Return True if it's a NewType declaration. The current target may be |
| 58 | deferred as a side effect if the base type is not ready, even if |
| 59 | the return value is True. |
| 60 | |
| 61 | The logic in this function mostly copies the logic for visit_class_def() |
| 62 | with a single (non-Generic) base. |
| 63 | """ |
| 64 | var_name, call = self.analyze_newtype_declaration(s) |
| 65 | if var_name is None or call is None: |
| 66 | return False |
| 67 | name = var_name |
| 68 | # OK, now we know this is a NewType. But the base type may be not ready yet, |
| 69 | # add placeholder as we do for ClassDef. |
| 70 | |
| 71 | if self.api.is_func_scope(): |
| 72 | name += "@" + str(s.line) |
| 73 | fullname = self.api.qualified_name(name) |
| 74 | |
| 75 | if not call.analyzed or isinstance(call.analyzed, NewTypeExpr) and not call.analyzed.info: |
| 76 | # Start from labeling this as a future class, as we do for normal ClassDefs. |
| 77 | placeholder = PlaceholderNode(fullname, s, s.line, becomes_typeinfo=True) |
| 78 | self.api.add_symbol(var_name, placeholder, s, can_defer=False) |
| 79 | |
| 80 | old_type, should_defer = self.check_newtype_args(var_name, call, s) |
| 81 | old_type = get_proper_type(old_type) |
| 82 | if not isinstance(call.analyzed, NewTypeExpr): |
| 83 | call.analyzed = NewTypeExpr(var_name, old_type, line=call.line, column=call.column) |
| 84 | else: |
| 85 | call.analyzed.old_type = old_type |
| 86 | if old_type is None: |
| 87 | if should_defer: |
| 88 | # Base type is not ready. |
| 89 | self.api.defer() |
| 90 | return True |
| 91 | |
| 92 | # Create the corresponding class definition if the aliased type is subtypeable |
| 93 | assert isinstance(call.analyzed, NewTypeExpr) |
| 94 | if isinstance(old_type, TupleType): |
| 95 | newtype_class_info = self.build_newtype_typeinfo( |
| 96 | name, old_type, old_type.partial_fallback, s.line, call.analyzed.info |
| 97 | ) |
| 98 | newtype_class_info.update_tuple_type(old_type) |
| 99 | elif isinstance(old_type, Instance): |
| 100 | if old_type.type.is_protocol: |
| 101 | self.fail("NewType cannot be used with protocol classes", s) |
| 102 | newtype_class_info = self.build_newtype_typeinfo( |
| 103 | name, old_type, old_type, s.line, call.analyzed.info |
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