When doing constraint type inference, we must consider whether the
constraint's core type is precise (no tilde) or imprecise (tilde,
or not a single specific type). In the latter case, we cannot infer
an unknown type argument from the (imprecise) core type because there
are infinitely many possible types. For instance, given
[E ~byte]
if we don't know E, we cannot infer that E must be byte (it could be
myByte, etc.). On the other hand, if we do know the type argument,
say for S in this example:
[S ~[]E, E any]
we must consider the underlying type of S when matching against ~[]E
because we have a tilde.
Because constraint type inference may infer type arguments that were
not eligible initially (because they were unknown and the core type
is imprecise), we must iterate the process until nothing changes any-
more. For instance, given
[S ~[]E, M ~map[string]S, E any]
where we initially only know the type argument for M, we must ignore
S (and E) at first. After one iteration of constraint type inference,
S is known at which point we can infer E as well.
The change is large-ish but the actual functional changes are small:
- There's a new method "unknowns" to determine the number of as of yet
unknown type arguments.
- The adjCoreType function has been adjusted to also return tilde
and single-type information. This is now conveniently returned
as (*term, bool), and the function has been renamed to coreTerm.
- The original constraint type inference loop has been adjusted to
consider tilde information.
- This adjusted original constraint type inference loop has been
nested in another loop for iteration, together with some minimal
logic to control termination.
The remaining changes are modifications to tests:
- There's a substantial new test for this issue.
- Several existing test cases were adjusted to accomodate the
fact that they inferred incorrect types: tildes have been
removed throughout. Most of these tests are for pathological
cases.
- A couple of tests were adjusted where there was a difference
between the go/types and types2 version.
Fixes#51229.
Change-Id: If0bf5fb70ec22913b5a2da89adbf8a27fbc921d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/387977
Trust: Robert Griesemer <gri@golang.org>
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Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
The next CL will remove the -G flag, effectively hard-coding it to its
current default (-G=3).
Change-Id: Ib4743b529206928f9f1cca9fdb19989728327831
Reviewed-on: https://go-review.googlesource.com/c/go/+/388534
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Add (temporary) syntax.AllowTypeLists mode to control the
acceptance of type lists; the compiler doesn't set it,
but existing syntax and types2 tests do so that the code
remains exercised while it exists.
Adjust various tests to use the type set notation.
Change-Id: I798e607912552db6bfe38a7cd4324b74c6bf4d95
Reviewed-on: https://go-review.googlesource.com/c/go/+/347249
Trust: Robert Griesemer <gri@golang.org>
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Reviewed-by: Robert Findley <rfindley@google.com>
We don't usually reformat the test directory, but all of the files in
test/typeparam are syntactically valid. I suspect the misformattings
here are because developers aren't re-installing gofmt with
-tags=typeparams, not intentionally exercising non-standard
formatting.
Change-Id: I3767d480434c19225568f3c7d656dc8589197183
Reviewed-on: https://go-review.googlesource.com/c/go/+/338093
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Robert Griesemer <gri@golang.org>
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Reviewed-by: Robert Griesemer <gri@golang.org>
The general idea is that we now export/import typeparams, typeparam
lists for generic types and functions, and instantiated types
(instantiations of generic types with either new typeparams or concrete
types).
This changes the export format -- the next CL in the stack adds the
export versions and checks for it in the appropriate places.
We always export/import generic function bodies, using the same code
that we use for exporting/importing the bodies of inlineable functions.
To avoid complicated scoping, we consider all type params as unique and
give them unique names for types1. We therefore include the types2 ids
(subscripts) in the export format and re-create on import. We always
access the same unique types1 typeParam type for the same typeparam
name.
We create fully-instantiated generic types and functions in the original
source package. We do an extra NeedRuntimeType() call to make sure that
the correct DWARF information is written out. We call SetDupOK(true) for
the functions/methods to have the linker automatically drop duplicate
instantiations.
Other miscellaneous details:
- Export/import of typeparam bounds works for methods (but not
typelists) for now, but will change with the typeset changes.
- Added a new types.Instantiate function roughly analogous to the
types2.Instantiate function recently added.
- Always access methods info from the original/base generic type, since
the methods of an instantiated type are not filled in (in types2 or
types1).
- New field OrigSym in types.Type to keep track of base generic type
that instantiated type was based on. We use the generic type's symbol
(OrigSym) as the link, rather than a Type pointer, since we haven't
always created the base type yet when we want to set the link (during
types2 to types1 conversion).
- Added types2.AsTypeParam(), (*types2.TypeParam).SetId()
- New test minimp.dir, which tests use of generic function Min across
packages. Another test stringimp.dir, which also exports a generic
function Stringify across packages, where the type param has a bound
(Stringer) as well. New test pairimp.dir, which tests use of generic
type Pair (with no methods) across packages.
- New test valimp.dir, which tests use of generic type (with methods
and related functions) across packages.
- Modified several other tests (adder.go, settable.go, smallest.go,
stringable.go, struct.go, sum.go) to export their generic
functions/types to show that generic functions/types can be exported
successfully (but this doesn't test import).
Change-Id: Ie61ce9d54a46d368ddc7a76c41399378963bb57f
Reviewed-on: https://go-review.googlesource.com/c/go/+/319930
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
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Reviewed-by: Robert Griesemer <gri@golang.org>
For Builtin ops, we currently stay with using the old
typechecker to transform the call to a more specific expression
and possibly use more specific ops. However, for a bunch of the
ops, we delay calling the old typechecker if any of the args have
type params, for a variety of reasons.
In the near future, we will start creating separate functions that do
the same transformations as the old typechecker for calls, builtins,
indexing, comparisons, etc. These functions can then be called at noder
time for nodes with no type params, and at stenciling time for nodes
with type params.
Remove unnecessary calls to types1 typechecker for most kinds of
statements (still need it for SendStmt, AssignStmt, ReturnStmt, and
SelectStmt). In particular, we don't need it for RangeStmt, and this
avoids some complaints by the types1 typechecker on generic code.
Other small changes:
- Fix check on whether to delay calling types1-typechecker on type
conversions. Should check if HasTParam is true, rather than if the
type is directly a TYPEPARAM.
- Don't call types1-typechecker on an indexing operation if the left
operand has a typeparam in its type and is not obviously a TMAP,
TSLICE, or TARRAY. As above, we will eventually have to create a new
function that can do the required transformations (for complicated
cases) at noder time or stenciling time.
- Copy n.BuiltinOp in subster.node()
- The complex arithmetic example in absdiff.go now works.
- Added new tests double.go and append.go
- Added new example with a new() call in settable.go
Change-Id: I8f377afb6126cab1826bd3c2732aa8cdf1f7e0b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/301951
Run-TryBot: Dan Scales <danscales@google.com>
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Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
In the case of partially inferred type arguments, we need to use the
IndexExpr as the key in g.info.Inferred[] rather than the CallExpr.
Added an extra fromStrings1 call in the settable.go test that tests
partially inferred type arguments. This new call uses a new concrete
type SettableString as well.
I also added another implementation fromStrings3 (derived from a go2go
tests) that typechecks but intentionally causes a panic.
Change-Id: I74d35c5a741f72f37160a96fbec939451157f392
Reviewed-on: https://go-review.googlesource.com/c/go/+/300309
Run-TryBot: Dan Scales <danscales@google.com>
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Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Get instantiatiated generic types working with interfaces, including
typechecking assignments to interfaces and instantiating all the methods
properly. To get it all working, this change includes:
- Add support for substituting in interfaces in subster.typ()
- Fill in the info for the methods for all instantiated generic types,
so those methods will be available for later typechecking (by the old
typechecker) when assigning an instantiated generic type to an
interface. We also want those methods available so we have the list
when we want to instantiate all methods of an instantiated type. We
have both for instantiated types encountered during the initial noder
phase, and for instantiated types created during stenciling of a
function/method.
- When we first create a fully-instantiated generic type (whether
during initial noder2 pass or while instantiating a method/function),
add it to a list so that all of its methods will also be
instantiated. This is needed so that an instantiated type can be
assigned to an interface.
- Properly substitute type names in the names of instantiated methods.
- New accessor methods for types.Type.RParam.
- To deal with generic types which are empty structs (or just don't use
their type params anywhere), we want to set HasTParam if a named type
has any type params that are not fully instantiated, even if the
type param is not used in the type.
- In subst.typ() and elsewhere, always set sym.Def for a new forwarding
type we are creating, so we always create a single unique type for
each generic type instantiation. This handles recursion within a
type, and also recursive relationships across many types or methods.
We remove the seen[] hashtable, which was serving the same purpose,
but for subst.typ() only. We now handle all kinds of recursive types.
- We don't seem to need to force types.CheckSize() on
created/substituted generic types anymore, so commented out for now.
- Add an RParams accessor to types2.Signature, and also a new
exported types2.AsSignature() function.
Change-Id: If6c5dd98427b20bfe9de3379cc16f83df9c9b632
Reviewed-on: https://go-review.googlesource.com/c/go/+/298449
Run-TryBot: Dan Scales <danscales@google.com>
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Trust: Dan Scales <danscales@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
- Deal with closures in generic functions by fixing the stenciling code
- Deal with instantiated function values (instantiated generic
functions that are not immediately called) during stenciling. This
requires changing the OFUNCINST node to an ONAME node for the
appropriately instantiated function. We do this in a second pass,
since this is uncommon, but requires editing the tree at multiple
levels.
- Check global assignments (as well as functions) for generic function
instantiations.
- Fix a bug in (*subst).typ where a generic type in a generic function
may definitely not use all the type args of the function, so we need
to translate the rparams of the type based on the tparams/targs of
the function.
- Added new test combine.go that tests out closures in generic
functions and instantiated function values.
- Added one new variant to the settable test.
- Enabling inlining functions with closures for -G=3. (For now, set
Ntype on closures in -G=3 mode to keep compatibility with later parts
of compiler, and allow inlining of functions with closures.)
Change-Id: Iea63d5704c322e42e2f750a83adc8b44f911d4ec
Reviewed-on: https://go-review.googlesource.com/c/go/+/296269
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
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Trust: Dan Scales <danscales@google.com>
- Create the stencil name using targ.Type.String(), which handles cases
where, for example, a type argument is a pointer to a named type,
etc. *obj.
- Set name.Def properly for a new stenciled func (have the symbol point
back to the associated function node). Will be required when exporting.
- Add missing copying of Func field when making copies of Name nodes.
(On purpose (it seems), Name nodes don't have a copy() function, so
we have to copy all the needed fields explicitly.)
- Deal with nil type in subster.node(), which is the type of the return
value for a function that doesn't return anything.
- Fix min to match standard want/go form, and add in float tests. Changed
Got -> got in bunch of other typeparam tests.
- Add new tests index.go, settable.go, and smallest.go (similar to
examples in the type param proposal), some of which need the above
changes.
Change-Id: I09a72302bc1fd3635a326da92405222afa222e85
Reviewed-on: https://go-review.googlesource.com/c/go/+/291109
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
