Avoid NoReturn analysis for Any or Unknown calls#11419
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bschnurr wants to merge 3 commits intomicrosoft:mainfrom
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Avoid NoReturn analysis for Any or Unknown calls#11419bschnurr wants to merge 3 commits intomicrosoft:mainfrom
bschnurr wants to merge 3 commits intomicrosoft:mainfrom
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rchiodo
reviewed
May 6, 2026
rchiodo
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May 6, 2026
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Update subtype helper paths to short-circuit where the result is known. Fix allSubtypes to return the callback result from every, use allSubtypes in isTypeVarSame, use someSubtypes in derivesFromAnyOrUnknown, and return early in getLiteralTypeClassName and combineSameSizedTuples. Add direct typeUtils unit tests for allSubtypes, someSubtypes, derivesFromAnyOrUnknown, getLiteralTypeClassName, and combineSameSizedTuples. Validation: npm run build; npm run test:norebuild -- --runTestsByPath src/tests/typeUtils.test.ts --forceExit. Benchmark note: reran the benchmark worktree analyzer benchmark after porting these typeUtils fixes there. Full run passed and wrote analyzer-benchmark-2026-05-06T23-24-52-295Z.json. noreturn_heavy median was 5984.83ms vs 6094.10ms in the previous no-return-only run (-1.79%), which is small enough to treat as noise-level unless repeated.
bschnurr
commented
May 6, 2026
| if (isUnion(type)) { | ||
| return type.priv.subtypes.every((subtype) => { | ||
| callback(subtype); | ||
| return callback(subtype); |
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every expects the return result from callback
bschnurr
commented
May 6, 2026
| const subtypeLiteralTypeName = getLiteralTypeClassName(subtype); | ||
| if (!subtypeLiteralTypeName) { | ||
| foundMismatch = true; | ||
| return undefined; |
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Diff from mypy_primer, showing the effect of this PR on open source code: sympy (https://github.com/sympy/sympy)
- .../projects/sympy/sympy/solvers/tests/test_solvers.py:1214:18 - error: Operator "+" not supported for types "Basic" and "Expr" (reportOperatorIssue)
- .../projects/sympy/sympy/solvers/tests/test_solveset.py:445:30 - error: Cannot access attribute "limit_denominator" for class "NaN"
- Attribute "limit_denominator" is unknown (reportAttributeAccessIssue)
- .../projects/sympy/sympy/solvers/tests/test_solveset.py:445:30 - error: Cannot access attribute "limit_denominator" for class "ComplexInfinity"
- Attribute "limit_denominator" is unknown (reportAttributeAccessIssue)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:315:25 - error: "Set" is not iterable
+ "__iter__" method not defined (reportGeneralTypeIssues)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:315:25 - error: "ConditionSet" is not iterable
+ "__iter__" method not defined (reportGeneralTypeIssues)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2024:20 - error: "__getitem__" method not defined on type "Basic" (reportIndexIssue)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2036:20 - error: "__getitem__" method not defined on type "Basic" (reportIndexIssue)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2049:20 - error: "__getitem__" method not defined on type "Basic" (reportIndexIssue)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2070:16 - error: Argument of type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" is not assignable to type "Sized"
+ "Set" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2071:20 - error: "__getitem__" method not defined on type "Basic" (reportIndexIssue)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2252:16 - error: Argument of type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" is not assignable to type "Sized"
+ "Set" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2333:16 - error: Argument of type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" is not assignable to type "Sized"
+ "Set" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2346:16 - error: Argument of type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" is not assignable to type "Sized"
+ "Set" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2352:16 - error: Argument of type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" is not assignable to type "Sized"
+ "Set" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2519:16 - error: Argument of type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | FiniteSet | Set | Intersection | Union | Complement | Any | ConditionSet" is not assignable to type "Sized"
+ "Set" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
+ .../projects/sympy/sympy/solvers/tests/test_solveset.py:2522:20 - error: Argument of type "Unknown | Basic | Any" cannot be assigned to parameter "obj" of type "Sized" in function "len"
+ Type "Unknown | Basic | Any" is not assignable to type "Sized"
+ "Basic" is incompatible with protocol "Sized"
+ "__len__" is not present (reportArgumentType)
- .../projects/sympy/sympy/stats/crv_types.py:2544:9 - error: Method "_cdf" overrides class "SingleContinuousDistribution" in an incompatible manner
- Return type mismatch: base method returns type "None", override returns type "ComplexInfinity | NaN | Rational | Unknown | Zero | Expr"
- Type "ComplexInfinity | NaN | Rational | Unknown | Zero | Expr" is not assignable to type "None"
- "Expr" is not assignable to "None" (reportIncompatibleMethodOverride)
- .../projects/sympy/sympy/stats/crv_types.py:2723:9 - error: Method "_cdf" overrides class "SingleContinuousDistribution" in an incompatible manner
- Return type mismatch: base method returns type "None", override returns type "Expr | NaN | ComplexInfinity | Rational | Unknown | One | NegativeOne | Zero | Integer"
- Type "Expr | NaN | ComplexInfinity | Rational | Unknown | One | NegativeOne | Zero | Integer" is not assignable to type "None"
- "Expr" is not assignable to "None" (reportIncompatibleMethodOverride)
- .../projects/sympy/sympy/stats/drv.py:269:22 - error: Argument of type "Generator[tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Add | Zero | NaN | Piecewise | Basic | int | None, None, None]" cannot be assigned to parameter "iterable" of type "Iterable[_SupportsSumNoDefaultT@sum]" in function "sum"
+ .../projects/sympy/sympy/stats/drv.py:269:22 - error: Argument of type "Generator[tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Zero | NaN | Piecewise | Basic | int | None, None, None]" cannot be assigned to parameter "iterable" of type "Iterable[_SupportsSumNoDefaultT@sum]" in function "sum"
- "Generator[tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Add | Zero | NaN | Piecewise | Basic | int | None, None, None]" is not assignable to "Iterable[_SupportsSumNoDefaultT@sum]"
+ "Generator[tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Zero | NaN | Piecewise | Basic | int | None, None, None]" is not assignable to "Iterable[_SupportsSumNoDefaultT@sum]"
- Type parameter "_T_co@Iterable" is covariant, but "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Add | Zero | NaN | Piecewise | Basic | int | None" is not a subtype of "_SupportsSumNoDefaultT@sum"
+ Type parameter "_T_co@Iterable" is covariant, but "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Zero | NaN | Piecewise | Basic | int | None" is not a subtype of "_SupportsSumNoDefaultT@sum"
- Type "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Add | Zero | NaN | Piecewise | Basic | int | None" is not assignable to type "_SupportsSumWithNoDefaultGiven"
+ Type "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Zero | NaN | Piecewise | Basic | int | None" is not assignable to type "_SupportsSumWithNoDefaultGiven"
- Type "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Add | Zero | NaN | Piecewise | Basic | int | None" is not assignable to type "_SupportsSumWithNoDefaultGiven"
+ Type "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Zero | NaN | Piecewise | Basic | int | None" is not assignable to type "_SupportsSumWithNoDefaultGiven"
- .../projects/sympy/sympy/stats/drv_types.py:293:16 - error: Operator "*" not supported for types "Expr" and "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Add | Zero | NaN | Piecewise | Basic"
+ .../projects/sympy/sympy/stats/drv_types.py:293:16 - error: Operator "*" not supported for types "Expr" and "tuple[Unknown, ...] | Unknown | Sum | Expr | ZeroMatrix | Zero | NaN | Piecewise | Basic"
- .../projects/sympy/sympy/stats/frv_types.py:139:17 - error: Argument of type "NaN | ComplexInfinity | Rational | Unknown | Expr" cannot be assigned to parameter "value" of type "int" in function "__setitem__"
- Type "NaN | ComplexInfinity | Rational | Unknown | Expr" is not assignable to type "int"
- "Expr" is not assignable to "int" (reportArgumentType)
- .../projects/sympy/sympy/stats/joint_rv_types.py:576:27 - error: Argument of type "One | NegativeOne | Zero | Integer | NaN | ComplexInfinity | Rational | Infinity | NegativeInfinity | Float | Number | Expr" cannot be assigned to parameter "stop" of type "SupportsIndex" in function "__new__"
+ .../projects/sympy/sympy/stats/joint_rv_types.py:576:27 - error: Argument of type "One | NegativeOne | Zero | Integer | NaN | ComplexInfinity | Rational | Unknown | Infinity | NegativeInfinity | Float | Number | Expr" cannot be assigned to parameter "stop" of type "SupportsIndex" in function "__new__"
- Type "One | NegativeOne | Zero | Integer | NaN | ComplexInfinity | Rational | Infinity | NegativeInfinity | Float | Number | Expr" is not assignable to type "SupportsIndex"
+ Type "One | NegativeOne | Zero | Integer | NaN | ComplexInfinity | Rational | Unknown | Infinity | NegativeInfinity | Float | Number | Expr" is not assignable to type "SupportsIndex"
... (truncated 754 lines) ...
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Summary
Fixes NoReturn reachability analysis for call targets that include
AnyorUnknown.A call target like
Unknown | Callable[..., NoReturn]cannot establish a guaranteedNoReturnresult. Previously, the callable subtype could be counted as NoReturn while theUnknownsubtype did not force a negative result, so code after the call could be incorrectly marked unreachable.This change makes
isCallNoReturnreturnfalseas soon as any call-target subtype isAnyorUnknown.This also tightens related
typeUtilssubtype helper usage so paths that are checking “any subtype” or “all subtypes” can short-circuit correctly and are covered by direct unit tests.Details
isCallNoReturnnow uses an explicit subtype loop so it can fail fast while analyzing the call target:The previous callback-local
returnfor custom metaclass__call__handling is preserved ascontinuein the explicit loop.The
typeUtilsfollow-up includes:allSubtypesso the union branch returns the callback result from.every.allSubtypesinisTypeVarSame.someSubtypesinderivesFromAnyOrUnknown, checking each subtype rather than the original union.getLiteralTypeClassNameand reject mixed literal classes as documented.combineSameSizedTupleswhen a subtype cannot participate.Tests
Added regression cases for mixed
Unknown/AnyplusCallable[..., NoReturn]call targets, and added directtypeUtilsunit coverage for:allSubtypessomeSubtypesderivesFromAnyOrUnknowngetLiteralTypeClassNamecombineSameSizedTuplesValidation run for the latest commit:
Earlier validation on the NoReturn regression path:
Earlier results:
Benchmark
I used a benchmark-branch-only generated analyzer benchmark,
noreturn_heavy, to stress this specific path with repeated mixedUnknown/Any+Callable[..., NoReturn]call-target cases.Initial focused analyzer benchmark results:
Delta on the focused benchmark:
After the
typeUtilsfollow-up, I updated the benchmark worktree with the same helper fixes and reran the full analyzer benchmark. New result file:Full analyzer benchmark medians from that run:
Compared with the prior
noreturn_heavy-only run:I would characterize the performance impact as a targeted improvement for NoReturn-heavy mixed
Any/Unknowncall-target cases. The latest full benchmark still points in the same direction fornoreturn_heavy, but the additional delta is small enough to treat as noise-level unless repeated runs keep showing the same shape.Full NumPy CLI benchmarks were noisy and effectively neutral. Diagnostics and file counts matched across runs: