[ty] Use range instead of custom IntIterable (#21138)

## Summary

We previously didn't understand `range` and wrote these custom
`IntIterable`/`IntIterator` classes for tests. We can now remove them
and make the tests shorter in some places.

Author: sharkdp

crates/ty_python_semantic/resources/mdtest/attributes.md

@@ -300,14 +300,6 @@ reveal_type(c_instance.b)  # revealed: Unknown | list[Literal[2, 3]]
 #### Attributes defined in for-loop (unpacking)
 
 ```py
-class IntIterator:
-    def __next__(self) -> int:
-        return 1
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 class TupleIterator:
     def __next__(self) -> tuple[int, str]:
         return (1, "a")
@@ -320,7 +312,7 @@ class NonIterable: ...
 
 class C:
     def __init__(self):
-        for self.x in IntIterable():
+        for self.x in range(3):
             pass
 
         for _, self.y in TupleIterable():
@@ -378,14 +370,6 @@ reveal_type(c_instance.y)  # revealed: Unknown | int
 #### Attributes defined in comprehensions
 
 ```py
-class IntIterator:
-    def __next__(self) -> int:
-        return 1
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 class TupleIterator:
     def __next__(self) -> tuple[int, str]:
         return (1, "a")
@@ -398,19 +382,19 @@ class C:
     def __init__(self) -> None:
         # TODO: Should not emit this diagnostic
         # error: [unresolved-attribute]
-        [... for self.a in IntIterable()]
+        [... for self.a in range(3)]
         # TODO: Should not emit this diagnostic
         # error: [unresolved-attribute]
         # error: [unresolved-attribute]
         [... for (self.b, self.c) in TupleIterable()]
         # TODO: Should not emit this diagnostic
         # error: [unresolved-attribute]
         # error: [unresolved-attribute]
-        [... for self.d in IntIterable() for self.e in IntIterable()]
+        [... for self.d in range(3) for self.e in range(3)]
         # TODO: Should not emit this diagnostic
         # error: [unresolved-attribute]
-        [[... for self.f in IntIterable()] for _ in IntIterable()]
-        [[... for self.g in IntIterable()] for self in [D()]]
+        [[... for self.f in range(3)] for _ in range(3)]
+        [[... for self.g in range(3)] for self in [D()]]
 
 class D:
     g: int
@@ -2058,16 +2042,8 @@ mod.global_symbol = 1
 # TODO: this should be an error, but we do not understand list unpackings yet.
 [_, mod.global_symbol] = [1, 2]
 
-class IntIterator:
-    def __next__(self) -> int:
-        return 42
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 # error: [invalid-assignment] "Object of type `int` is not assignable to attribute `global_symbol` of type `str`"
-for mod.global_symbol in IntIterable():
+for mod.global_symbol in range(3):
     pass
 ```
 

crates/ty_python_semantic/resources/mdtest/comprehensions/basic.md

@@ -3,71 +3,47 @@
 ## Basic comprehensions
 
 ```py
-class IntIterator:
-    def __next__(self) -> int:
-        return 42
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 # revealed: int
-[reveal_type(x) for x in IntIterable()]
+[reveal_type(x) for x in range(3)]
 
-class IteratorOfIterables:
-    def __next__(self) -> IntIterable:
-        return IntIterable()
+class Row:
+    def __next__(self) -> range:
+        return range(3)
 
-class IterableOfIterables:
-    def __iter__(self) -> IteratorOfIterables:
-        return IteratorOfIterables()
+class Table:
+    def __iter__(self) -> Row:
+        return Row()
 
-# revealed: tuple[int, IntIterable]
-[reveal_type((x, y)) for y in IterableOfIterables() for x in y]
+# revealed: tuple[int, range]
+[reveal_type((cell, row)) for row in Table() for cell in row]
 
 # revealed: int
-{reveal_type(x): 0 for x in IntIterable()}
+{reveal_type(x): 0 for x in range(3)}
 
 # revealed: int
-{0: reveal_type(x) for x in IntIterable()}
+{0: reveal_type(x) for x in range(3)}
 ```
 
 ## Nested comprehension
 
 ```py
-class IntIterator:
-    def __next__(self) -> int:
-        return 42
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 # revealed: tuple[int, int]
-[[reveal_type((x, y)) for x in IntIterable()] for y in IntIterable()]
+[[reveal_type((x, y)) for x in range(3)] for y in range(3)]
 ```
 
 ## Comprehension referencing outer comprehension
 
 ```py
-class IntIterator:
-    def __next__(self) -> int:
-        return 42
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
-class IteratorOfIterables:
-    def __next__(self) -> IntIterable:
-        return IntIterable()
+class Row:
+    def __next__(self) -> range:
+        return range(3)
 
-class IterableOfIterables:
-    def __iter__(self) -> IteratorOfIterables:
-        return IteratorOfIterables()
+class Table:
+    def __iter__(self) -> Row:
+        return Row()
 
-# revealed: tuple[int, IntIterable]
-[[reveal_type((x, y)) for x in y] for y in IterableOfIterables()]
+# revealed: tuple[int, range]
+[[reveal_type((cell, row)) for cell in row] for row in Table()]
 ```
 
 ## Comprehension with unbound iterable
@@ -79,17 +55,9 @@ Iterating over an unbound iterable yields `Unknown`:
 # revealed: Unknown
 [reveal_type(z) for z in x]
 
-class IntIterator:
-    def __next__(self) -> int:
-        return 42
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 # error: [not-iterable] "Object of type `int` is not iterable"
 # revealed: tuple[int, Unknown]
-[reveal_type((x, z)) for x in IntIterable() for z in x]
+[reveal_type((x, z)) for x in range(3) for z in x]
 ```
 
 ## Starred expressions
@@ -99,16 +67,8 @@ Starred expressions must be iterable
 ```py
 class NotIterable: ...
 
-class Iterator:
-    def __next__(self) -> int:
-        return 42
-
-class Iterable:
-    def __iter__(self) -> Iterator:
-        return Iterator()
-
 # This is fine:
-x = [*Iterable()]
+x = [*range(3)]
 
 # error: [not-iterable] "Object of type `NotIterable` is not iterable"
 y = [*NotIterable()]
@@ -138,16 +98,8 @@ This tests that we understand that `async` comprehensions do *not* work accordin
 iteration protocol
 
 ```py
-class Iterator:
-    def __next__(self) -> int:
-        return 42
-
-class Iterable:
-    def __iter__(self) -> Iterator:
-        return Iterator()
-
 async def _():
-    # error: [not-iterable] "Object of type `Iterable` is not async-iterable"
+    # error: [not-iterable] "Object of type `range` is not async-iterable"
     # revealed: Unknown
-    [reveal_type(x) async for x in Iterable()]
+    [reveal_type(x) async for x in range(3)]
 ```

crates/ty_python_semantic/resources/mdtest/comprehensions/invalid_syntax.md

@@ -1,22 +1,14 @@
 # Comprehensions with invalid syntax
 
 ```py
-class IntIterator:
-    def __next__(self) -> int:
-        return 42
-
-class IntIterable:
-    def __iter__(self) -> IntIterator:
-        return IntIterator()
-
 # Missing 'in' keyword.
 
 # It's reasonably clear here what they *meant* to write,
 # so we'll still infer the correct type:
 
 # error: [invalid-syntax] "Expected 'in', found name"
 # revealed: int
-[reveal_type(a) for a IntIterable()]
+[reveal_type(a) for a range(3)]
 
 
 # Missing iteration variable
@@ -25,7 +17,7 @@ class IntIterable:
 # error: [invalid-syntax] "Expected 'in', found name"
 # error: [unresolved-reference]
 # revealed: Unknown
-[reveal_type(b) for in IntIterable()]
+[reveal_type(b) for in range(3)]
 
 
 # Missing iterable