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go/test
Robert Griesemer 0807986fe6 go/types, types2: correctly consider ~ (tilde) in constraint type inference
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>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
2022-03-01 23:48:58 +00:00
..
abi
alias3.dir
asmhdr.dir cmd/compile: use exact constant in go_asm.h 2022-01-10 21:27:19 +00:00
bench
chan
closure3.dir cmd/compile/internal/inline: revise closure inl position fix 2021-11-24 15:55:56 +00:00
closure5.dir
codegen cmd/compile: include all entries in map literal hint size 2022-03-01 23:20:30 +00:00
ddd2.dir
dwarf
fixedbugs cmd/compile: use AutogeneratedPos for method value wrapper 2022-03-01 21:27:42 +00:00
import2.dir
import4.dir
interface cmd/compile: match Go 1.17 compiler error messages more closely 2021-11-12 23:07:01 +00:00
intrinsic.dir
ken test/ken/slicearray.go: correct type width in comment 2021-12-05 12:50:44 +00:00
linkname.dir cmd/compile: allow inlining of ORANGE 2021-10-28 14:25:03 +00:00
method4.dir
oldescape_linkname.dir
retjmp.dir cmd/internal/obj: fix tail call in non-zero frame leaf function on MIPS and S390X 2021-12-13 22:42:08 +00:00
runtime
stress
syntax
typeparam go/types, types2: correctly consider ~ (tilde) in constraint type inference 2022-03-01 23:48:58 +00:00
uintptrescapes.dir
64bit.go
235.go
alg.go
alias1.go
alias2.go cmd/compile: match Go 1.17 compiler error messages more closely 2021-11-12 23:07:01 +00:00
alias3.go
alias.go
align.go
append1.go cmd/compile: match Go 1.17 compiler error messages more closely 2021-11-12 23:07:01 +00:00
append.go
args.go
armimm.go
asmhdr.go cmd/compile: emit sensible go_asm.h consts for big ints 2021-10-30 18:30:05 +00:00
assign1.go
assign.go
atomicload.go
bigalg.go
bigmap.go
blank1.go
blank.go
bom.go
bombad.go
bounds.go
cannotassign.go
chancap.go
chanlinear.go
char_lit1.go
char_lit.go
checkbce.go
clearfat.go
closedchan.go
closure1.go
closure2.go
closure3.go
closure4.go
closure5.go
closure6.go
closure7.go
closure.go
cmp6.go
cmp.go
cmplx.go
cmplxdivide1.go
cmplxdivide.c
cmplxdivide.go
complit1.go
complit.go
compos.go
const1.go
const2.go
const3.go
const4.go
const5.go
const6.go
const7.go all: avoid use of cmd/compile -G flag in tests 2022-03-01 19:45:34 +00:00
const.go
convert1.go
convert2.go
convert3.go
convert4.go
convert.go
convlit1.go
convlit.go
convT2X.go
copy1.go
copy.go
crlf.go
ddd1.go cmd/compile: match Go 1.17 compiler error messages more closely 2021-11-12 23:07:01 +00:00
ddd2.go
ddd.go
decl.go
declbad.go
defer.go
defererrcheck.go
deferfin.go
defernil.go
deferprint.go
deferprint.out
devirt.go
directive2.go test: re-enable a bunch of tests with types2 2021-12-03 16:24:32 +00:00
directive.go test: re-enable a bunch of tests with types2 2021-12-03 16:24:32 +00:00
divide.go
divmod.go
embedfunc.go
embedvers.go
empty.go
env.go
eof1.go
eof.go
escape2.go
escape2n.go
escape3.go
escape4.go
escape5.go
escape_array.go
escape_calls.go
escape_closure.go
escape_field.go
escape_goto.go
escape_hash_maphash.go
escape_iface.go
escape_indir.go
escape_level.go
escape_map.go
escape_param.go
escape_runtime_atomic.go
escape_selfassign.go
escape_slice.go
escape_struct_param1.go
escape_struct_param2.go
escape_struct_return.go
escape_sync_atomic.go
escape_unsafe.go
escape.go
fibo.go
finprofiled.go
float_lit2.go
float_lit3.go test: re-enable a bunch of tests with types2 2021-12-03 16:24:32 +00:00
float_lit.go
floatcmp.go
for.go
func1.go
func2.go
func3.go
func4.go
func5.go
func6.go
func7.go
func8.go
func.go
funcdup2.go
funcdup.go
fuse.go
gc1.go
gc2.go
gc.go
gcgort.go
gcstring.go
goprint.go
goprint.out
goto.go
heapsampling.go
helloworld.go
helloworld.out
if.go
import1.go test: re-enable most go/tests that were disabled because of types2 differences 2022-01-11 02:26:58 +00:00
import2.go
import4.go
import5.go
import6.go test: re-enable most go/tests that were disabled because of types2 differences 2022-01-11 02:26:58 +00:00
import.go
index0.go
index1.go
index2.go
index.go
indirect1.go
indirect.go
init1.go
init.go
initcomma.go
initempty.go
initexp.go
initialize.go
initializerr.go test: re-enable most go/tests that were disabled because of types2 differences 2022-01-11 02:26:58 +00:00
initloop.go
inline_big.go
inline_caller.go
inline_callers.go
inline_endian.go
inline_literal.go
inline_math_bits_rotate.go
inline_sync.go
inline_variadic.go
inline.go cmd/compile/internal/inline: revise closure inl position fix 2021-11-24 15:55:56 +00:00
int_lit.go
intcvt.go
intrinsic_atomic.go
intrinsic.go
iota.go
label1.go
label.go
linkmain_run.go
linkmain.go
linkname2.go test: re-enable a bunch of tests with types2 2021-12-03 16:24:32 +00:00
linkname3.go test: re-enable a bunch of tests with types2 2021-12-03 16:24:32 +00:00
linkname.go
linkobj.go
linkx_run.go
linkx.go
literal2.go
literal.go
live1.go
live2.go
live_regabi.go
live_syscall.go
live.go
locklinear.go
loopbce.go
mainsig.go
makechan.go
makemap.go
makenew.go
makeslice.go
mallocfin.go
map1.go
map.go
mapclear.go
maplinear.go
maymorestack.go cmd/{asm,compile,internal/obj}: add "maymorestack" support 2021-11-05 00:52:06 +00:00
mergemul.go
method1.go
method2.go go/types, types2: better error message when using *interface instead of interface 2022-01-10 22:48:40 +00:00
method3.go
method4.go
method5.go
method6.go
method7.go
method.go
named1.go
named.go
nil.go
nilcheck.go
nilptr2.go
nilptr3.go
nilptr4.go
nilptr5_aix.go
nilptr5_wasm.go
nilptr5.go
nilptr_aix.go
nilptr.go
nosplit.go
notinheap2.go
notinheap3.go
notinheap.go
nowritebarrier.go
nul1.go
opt_branchlikely.go
parentype.go
peano.go
phiopt.go
print.go
print.out
printbig.go
printbig.out
prove.go
range.go
README.md
recover1.go
recover2.go
recover3.go
recover4.go test/recover4.go: use mprotect to create a hole instead of munmap 2021-11-12 16:58:34 +00:00
recover5.go
recover.go
reflectmethod1.go
reflectmethod2.go
reflectmethod3.go
reflectmethod4.go
reflectmethod5.go
reflectmethod6.go
reflectmethod7.go all: use reflect.{Pointer,PointerTo} 2021-10-26 14:24:17 +00:00
reflectmethod8.go
rename1.go
rename.go
reorder2.go
reorder.go
retjmp.go
return.go
rotate0.go
rotate1.go
rotate2.go
rotate3.go
rotate.go
run.go all: avoid use of cmd/compile -G flag in tests 2022-03-01 19:45:34 +00:00
rune.go
runtime.go
shift1.go test: re-enable a bunch of tests with types2 2021-12-03 16:24:32 +00:00
shift2.go
sieve.go
sigchld.go
sigchld.out
simassign.go
sinit_run.go
sinit.go
sizeof.go
slice3.go
slice3err.go
slicecap.go
sliceopt.go
solitaire.go
stack.go
stackobj2.go
stackobj3.go
stackobj.go
strcopy.go
strength.go
string_lit.go
stringrange.go
struct0.go
switch2.go
switch3.go
switch4.go
switch5.go
switch6.go
switch7.go
switch.go
tinyfin.go
torture.go
turing.go
typecheck.go test: re-enable most go/tests that were disabled because of types2 differences 2022-01-11 02:26:58 +00:00
typecheckloop.go
typeswitch1.go
typeswitch2.go
typeswitch2b.go
typeswitch3.go cmd/compile/internal/types2: better error for type assertion/switch on type parameter value 2021-11-12 22:20:51 +00:00
typeswitch.go
uintptrescapes2.go
uintptrescapes3.go
uintptrescapes.go
undef.go
unsafebuiltins.go
used.go
utf.go
varerr.go
varinit.go
winbatch.go
writebarrier.go
zerodivide.go

The test directory contains tests of the Go tool chain and runtime. It includes black box tests, regression tests, and error output tests. They are run as part of all.bash.

To run just these tests, execute:

../bin/go run run.go

To run just tests from specified files in this directory, execute:

../bin/go run run.go -- file1.go file2.go ...

Standard library tests should be written as regular Go tests in the appropriate package.

The tool chain and runtime also have regular Go tests in their packages. The main reasons to add a new test to this directory are:

  • it is most naturally expressed using the test runner; or
  • it is also applicable to gccgo and other Go tool chains.