Diagnostics¶

This page lists every code the checker, the converter, and the backends emit. Each diagnostic has a stable code (spec 29.1).

E codes are errors, W codes are warnings, and R codes are remarks.
ppy explain E1301 prints the description of a code.
--no-strict downgrades the strict-mode errors that have a sound fallback. It never downgrades the rest.

Source and module structure¶

code	meaning
`E1001`	The source could not be parsed by the configured CPython grammar.
`E1002`	The source file could not be read.
`E1003`	A module is provided by both a .py and a .ppy source under the same qualified name.

code	meaning
`E1101`	A name is used before any binding reaches it.
`E1102`	An import target could not be resolved to a module in the project or environment.
`E1103`	A `from ... import *` makes the module namespace unanalyzable.

code	meaning
`E1201`	A parameter has no annotation and no inferable type, which would introduce an implicit `Any`.
`E1202`	An attribute could not be resolved on a statically known type.
`E1203`	A generic type was used bare, which would introduce an implicit `Any` element type.
`E1204`	A decorator applies an unknown transform, so the decorated signature is unknown.
`E1205`	A `ppy.` decorator names a directive the runtime does not export.
`E1206`	An attribute was read through a value that may be `None`.

code	meaning
`E1301`	An assignment or argument does not match the declared type.
`E1302`	An operator has no definition for the operand types.
`E1303`	A returned value does not match the declared return type.
`E1304`	A stable type could not be inferred for a parameter or local.
`E1305`	A call does not match the callee's parameter list.
`E1306`	A callable's signature is unknown, so the call cannot be typed.

code	meaning
`E1401`	A value provably leaves the range promised by a fixed-width marker.
`E1402`	A fixed-width contract needs a runtime check that the selected contract mode forbids.

code	meaning
`E1501`	`eval`, `exec`, or runtime code-object construction is not statically analyzable.
`E1502`	Mutation of `globals()`, `locals()`, or frame locals is not statically analyzable.
`E1503`	An import target is not a compile-time constant.
`E1504`	A dynamic Python feature requires an explicit `ppy.dynamic` boundary.
`E1505`	A dynamic boundary is forbidden by the project configuration.
`E1506`	Attribute or class mutation after analysis is not supported.
`E1507`	A class is constructed dynamically, from computed bases or an unvouched metaclass.
`E1508`	A dynamic value crosses into typed code without a `ppy.check[T]` conversion.

code	meaning
`E1601`	A function declared `@ppy.pure` performs a forbidden effect.
`E1602`	A function declared `@ppy.pure` calls a function with unknown effects.

code	meaning
`E1611`	A function returns a parameter it only borrows.
`E1612`	A function stores a borrowed parameter where it outlives the call.
`E1613`	A function writes through a parameter it borrows read-only; `Mut[...]` allows the write.

code	meaning
`E1720`	A type parameter form other than `T` or `T: Bound` (a `ParamSpec`, a `TypeVarTuple`).
`E1721`	A type argument does not satisfy its parameter's bound.
`E1722`	A generic is specialized on more type-argument tuples, or a deeper type, than `[tool.ppy.generics]` allows.
`E1723`	A generic calls itself with its own type parameter nested in a type: the specializations never end.

code	meaning
`E1630`	A `ppy.native` operation was given something that is not a native pointer.
`E1631`	A write through a `ppy.native.const_ptr`.
`E1632`	A C export needs a signature C can spell, with one scalar result.
`E1633`	A C binding needs every parameter and its return annotated.
`E1640`	A `ppy.simd` operation is misused; the message says how.
`E1641`	A `ppy.atomic` operation is misused; the message says how.
`E1642`	A `ppy.concurrent` operation is misused; the message says how.
`E1643`	A `ppy.cpu` operation is misused; the message says how.
`E1644`	A `ppy.cuda` or `ppy.hip` operation is misused; the message says how.
`E1645`	A `ppy.aio` operation is misused; the message says how.
`E1650`	A `ppy.parallel` loop is misused; the message says how.
`E1660`	`ppy.grad` or `ppy.value_and_grad` is misused; the message says how.
`E1661`	A function cannot be differentiated as typed: it must return `float`, and `argnums` names `float` parameters.
`E1662`	A function with an effect no derivative follows (I/O, a write, a thread) is differentiated.

code	meaning
`E1701`	`@ppy.parallel(require=True)` could not be satisfied for the selected backend.
`E1702`	`@ppy.native(require=True)` could not be satisfied without an opaque Python call.

code	meaning
`E1801`	The selected backend is unavailable in this environment.
`E1802`	A construct is not supported by the selected backend.
`E1803`	A standalone build requires a fully native reachable graph.
`E1804`	A header-only unit cannot carry runtime state; the feature needing it is named.
`E1805`	A library build has nothing to export; `@ppy.native.export` names what to publish.
`E1806`	A C header could not be imported; the reason is named.

code	meaning
`E1901`	A plugin the project asked for could not be loaded, or two plugins claim one module.
`E1902`	A plugin's compiler pass left the IR invalid; the pass is named.
`E1903`	A backend could not be used: unknown, registered twice, written against another interface version, or not loadable; the reason is named.
`E1904`	A backend's compiler pass left the IR invalid; the pass is named.

code	meaning
`R3001`	An optimization remark.
`R3002`	The converter promoted a list parameter to a borrowed buffer.
`R3003`	A list parameter is close to being a borrowed buffer but something blocks it.
`R3004`	A native-eligible function stays on the Python boundary; crossing costs more than it saves.

code	meaning
`W2001`	A module is shadowed by a same-named source with a different extension.
`W2002`	A `bool` value takes part in arithmetic, which is legal but usually unintended.
`W2003`	Unknown `Annotated` metadata was preserved but not interpreted.
`W2004`	A directive had no effect for the selected backend.
`W2005`	Conversion left both a .py and a .ppy source for the same module.
`W2006`	Errors that only restated a type the analysis could not resolve were withheld; the count and the unresolved origins are reported once.
`W2007`	A function marked `@ppy.xla.jit` cannot be taken by XLA; the reason is named.
`W2008`	A kernel will not run on the device; the reason is named, and the reference runs.
`W2009`	A function changed since the profile given to `--pgo` was recorded; its counts were ignored and it was built as without a profile.
`W2101`	The build cache index was damaged; it was quarantined and rebuilt, and compilation continued with cache misses.

code	meaning
`E9001`	An internal analysis failed to converge; the result cannot be trusted.