add test for partially overlapping overloads

Author: carljm

conformance/results/mypy/overloads_overlap.toml

@@ -0,0 +1,7 @@
+conformant = "Pass"
+conformance_automated = "Pass"
+errors_diff = """
+"""
+output = """
+overloads_overlap.py:14: error: Overloaded function signatures 1 and 2 overlap with incompatible return types  [overload-overlap]
+"""

conformance/results/mypy/version.toml

@@ -1,2 +1,2 @@
 version = "mypy 1.14.1"
-test_duration = 1.8
+test_duration = 1.7

conformance/results/pyre/overloads_overlap.toml

@@ -0,0 +1,10 @@
+conformant = "Fail"
+notes = """
+Does not check for overlapping overloads with inconsistent return type.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 14: Expected 1 errors
+"""
+output = """
+"""

conformance/results/pyre/version.toml

@@ -1,2 +1,2 @@
 version = "pyre 0.9.23"
-test_duration = 6.0
+test_duration = 6.7

conformance/results/pyright/overloads_overlap.toml

@@ -0,0 +1,7 @@
+conformant = "Pass"
+conformance_automated = "Pass"
+errors_diff = """
+"""
+output = """
+overloads_overlap.py:14:5 - error: Overload 1 for "is_one" overlaps overload 2 and returns an incompatible type (reportOverlappingOverload)
+"""

conformance/results/pyright/version.toml

@@ -1,2 +1,2 @@
 version = "pyright 1.1.391"
-test_duration = 1.7
+test_duration = 1.5

conformance/results/pytype/overloads_overlap.toml

@@ -0,0 +1,16 @@
+conformant = "Fail"
+notes = """
+Does not check for overlapping overloads with inconsistent return type.
+"""
+conformance_automated = "Fail"
+errors_diff = """
+Line 14: Expected 1 errors
+Line 22: Unexpected errors ['overloads_overlap.py:22:5: \\x1b[1m\\x1b[31merror\\x1b[39m\\x1b[0m: in is_one: bad return type [bad-return-type]']
+"""
+output = """
+overloads_overlap.py:22:5: \u001b[1m\u001b[31merror\u001b[39m\u001b[0m: in is_one: bad return type [bad-return-type]
+
+    return x == 1
+    \u001b[1m\u001b[31m~~~~~~~~~~~~~\u001b[39m\u001b[0m
+
+"""

conformance/results/pytype/version.toml

@@ -1,2 +1,2 @@
 version = "pytype 2024.10.11"
-test_duration = 31.1
+test_duration = 32.1

conformance/results/results.html

@@ -159,16 +159,16 @@ <h3>Python Type System Conformance Test Results</h3>
         <div class="table_container"><table><tbody>
 <tr><th class="col1">&nbsp;</th>
 <th class='tc-header'><div class='tc-name'>mypy 1.14.1</div>
-<div class='tc-time'>1.8sec</div>
+<div class='tc-time'>1.7sec</div>
 </th>
 <th class='tc-header'><div class='tc-name'>pyright 1.1.391</div>
-<div class='tc-time'>1.7sec</div>
+<div class='tc-time'>1.5sec</div>
 </th>
 <th class='tc-header'><div class='tc-name'>pyre 0.9.23</div>
-<div class='tc-time'>6.0sec</div>
+<div class='tc-time'>6.7sec</div>
 </th>
 <th class='tc-header'><div class='tc-name'>pytype 2024.10.11</div>
-<div class='tc-time'>31.1sec</div>
+<div class='tc-time'>32.1sec</div>
 </th>
 </tr>
 <tr><th class="column" colspan="5">
@@ -675,7 +675,7 @@ <h3>Python Type System Conformance Test Results</h3>
 <tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;overloads_consistency</th>
 <th class="column col2 conformant">Pass</th>
 <th class="column col2 conformant">Pass</th>
-<th class="column col2 conformant">Pass</th>
+<th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Does not apply decorator transforms before checking overload consistency.</p></span></div></th>
 <th class="column col2 not-conformant"><div class="hover-text">Fail<span class="tooltip-text" id="bottom"><p>Doesn't appear to validate overload consistency at all.</p></span></div></th>
 </tr>
 <tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;overloads_definitions</th>
@@ -690,6 +690,12 @@ <h3>Python Type System Conformance Test Results</h3>
 <th class="column col2 partially-conformant"><div class="hover-text">Partial<span class="tooltip-text" id="bottom"><p>Expects @final and @override to be present on all overloads, not just first.</p></span></div></th>
 <th class="column col2 not-conformant"><div class="hover-text">Fail<span class="tooltip-text" id="bottom"><p>Does not enforce any of the specified rules regarding overload definitions.</p></span></div></th>
 </tr>
+<tr><th class="column col1">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;overloads_overlap</th>
+<th class="column col2 conformant">Pass</th>
+<th class="column col2 conformant">Pass</th>
+<th class="column col2 not-conformant"><div class="hover-text">Fail<span class="tooltip-text" id="bottom"><p>Does not check for overlapping overloads with inconsistent return type.</p></span></div></th>
+<th class="column col2 not-conformant"><div class="hover-text">Fail<span class="tooltip-text" id="bottom"><p>Does not check for overlapping overloads with inconsistent return type.</p></span></div></th>
+</tr>
 <tr><th class="column" colspan="5">
 <a class="test_group" href="https://typing.readthedocs.io/en/latest/spec/exceptions.html">Exceptions</a>
 </th></tr>

conformance/tests/overloads_overlap.py

@@ -0,0 +1,22 @@
+"""
+Tests checks for overlapping overloads.
+"""
+
+from typing import Literal, overload
+
+# > If two overloads can accept the same set of arguments, they are said
+# > to "partially overlap". If two overloads partially overlap, the return type
+# > of the former overload should be assignable to the return type of the
+# > latter overload. If this condition doesn't hold, it is indicative of a
+# > programming error and should be reported by type checkers.
+
+@overload
+def is_one(x: Literal[1]) -> Literal[True]:  # E: overlapping overloads, inconsistent return type
+    ...
+
+@overload
+def is_one(x: int) -> Literal[False]:
+    ...
+
+def is_one(x: int) -> bool:
+    return x == 1