[go] types2: method recv type parameter count must match base type parameter count
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Robert Griesemer (Gerrit)
Feb 24, 2022, 5:11:28 PM2/24/22
to Robert Griesemer, goph...@pubsubhelper.golang.org, golang-...@googlegroups.com, Gopher Robot, Robert Findley, David Chase, golang-co...@googlegroups.com
Robert Griesemer submitted this change.
2 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.
Approvals:
David Chase: Looks good to me, approved
Robert Findley: Looks good to me, approved
Robert Griesemer: Trusted
go/types, types2: method recv type parameter count must match base type parameter count
Check receiver type parameter count when type checking the method
signature and report a suitable error (don't rely on delayed
instantiation and possibly constraint type inference).
While at it, simplify blank name recoding and type bound rewriting.
Stop-gap measure to avoid crashes in the compiler.
Fixes #51339.
For #51343.
Change-Id: Idbe2d32d69b66573ca973339f8924b349d2bc9cc
Reviewed-on: https://go-review.googlesource.com/c/go/+/387836
Trust: Robert Griesemer <g...@golang.org>
Reviewed-by: David Chase <drc...@google.com>
Reviewed-by: Robert Findley <rfin...@google.com>
---
M src/cmd/compile/internal/types2/assignments.go
M src/cmd/compile/internal/types2/signature.go
A src/cmd/compile/internal/types2/testdata/fixedbugs/issue51339.go2
M src/go/types/assignments.go
M src/go/types/signature.go
A src/go/types/testdata/fixedbugs/issue51339.go2
6 files changed, 104 insertions(+), 49 deletions(-)
diff --git a/src/cmd/compile/internal/types2/assignments.go b/src/cmd/compile/internal/types2/assignments.go
index 936930f..d88b037 100644
--- a/src/cmd/compile/internal/types2/assignments.go
+++ b/src/cmd/compile/internal/types2/assignments.go
@@ -294,15 +294,14 @@
return "(" + strings.Join(res, ", ") + ")"
}
-func (check *Checker) assignError(rhs []syntax.Expr, nvars, nvals int) {
- measure := func(x int, unit string) string {
- s := fmt.Sprintf("%d %s", x, unit)
- if x != 1 {
- s += "s"
- }
- return s
+func measure(x int, unit string) string {
+ if x != 1 {
+ unit += "s"
}
+ return fmt.Sprintf("%d %s", x, unit)
+}
+func (check *Checker) assignError(rhs []syntax.Expr, nvars, nvals int) {
vars := measure(nvars, "variable")
vals := measure(nvals, "value")
rhs0 := rhs[0]
diff --git a/src/cmd/compile/internal/types2/signature.go b/src/cmd/compile/internal/types2/signature.go
index c87fab7..76e5882 100644
--- a/src/cmd/compile/internal/types2/signature.go
+++ b/src/cmd/compile/internal/types2/signature.go
@@ -116,11 +116,10 @@
// lookup in the scope.
for i, p := range rparams {
if p.Value == "_" {
- tpar := sig.rparams.At(i)
if check.recvTParamMap == nil {
check.recvTParamMap = make(map[*syntax.Name]*TypeParam)
}
- check.recvTParamMap[p] = tpar
+ check.recvTParamMap[p] = tparams[i]
}
}
// determine receiver type to get its type parameters
@@ -136,22 +135,23 @@
}
}
// provide type parameter bounds
- // - only do this if we have the right number (otherwise an error is reported elsewhere)
- if sig.RecvTypeParams().Len() == len(recvTParams) {
- // We have a list of *TypeNames but we need a list of Types.
- list := make([]Type, sig.RecvTypeParams().Len())
- for i, t := range sig.RecvTypeParams().list() {
- list[i] = t
- check.mono.recordCanon(t, recvTParams[i])
+ if len(tparams) == len(recvTParams) {
+ smap := makeRenameMap(recvTParams, tparams)
+ for i, tpar := range tparams {
+ recvTPar := recvTParams[i]
+ check.mono.recordCanon(tpar, recvTPar)
+ // recvTPar.bound is (possibly) parameterized in the context of the
+ // receiver type declaration. Substitute parameters for the current
+ // context.
+ tpar.bound = check.subst(tpar.obj.pos, recvTPar.bound, smap, nil)
}
- smap := makeSubstMap(recvTParams, list)
- for i, tpar := range sig.RecvTypeParams().list() {
- bound := recvTParams[i].bound
- // bound is (possibly) parameterized in the context of the
- // receiver type declaration. Substitute parameters for the
- // current context.
- tpar.bound = check.subst(tpar.obj.pos, bound, smap, nil)
- }
+ } else if len(tparams) < len(recvTParams) {
+ // Reporting an error here is a stop-gap measure to avoid crashes in the
+ // compiler when a type parameter/argument cannot be inferred later. It
+ // may lead to follow-on errors (see issues #51339, #51343).
+ // TODO(gri) find a better solution
+ got := measure(len(tparams), "type parameter")
+ check.errorf(recvPar, "got %s, but receiver base type declares %d", got, len(recvTParams))
}
}
}
diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue51339.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue51339.go2
new file mode 100644
index 0000000..40706ec
--- /dev/null
+++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue51339.go2
@@ -0,0 +1,16 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file is tested when running "go test -run Manual"
+// without source arguments. Use for one-off debugging.
+
+package p
+
+type T[P any, B *P] struct{}
+
+func (T /* ERROR cannot use generic type */ ) m0() {}
+func (T /* ERROR got 1 type parameter, but receiver base type declares 2 */ [_]) m1() {}
+func (T[_, _]) m2() {}
+// TODO(gri) this error is unfortunate (issue #51343)
+func (T /* ERROR got 3 arguments but 2 type parameters */ [_, _, _]) m3() {}
diff --git a/src/go/types/assignments.go b/src/go/types/assignments.go
index f75b8b6..f5e22c2 100644
--- a/src/go/types/assignments.go
+++ b/src/go/types/assignments.go
@@ -290,15 +290,14 @@
return "(" + strings.Join(res, ", ") + ")"
}
-func (check *Checker) assignError(rhs []ast.Expr, nvars, nvals int) {
- measure := func(x int, unit string) string {
- s := fmt.Sprintf("%d %s", x, unit)
- if x != 1 {
- s += "s"
- }
- return s
+func measure(x int, unit string) string {
+ if x != 1 {
+ unit += "s"
}
+ return fmt.Sprintf("%d %s", x, unit)
+}
+func (check *Checker) assignError(rhs []ast.Expr, nvars, nvals int) {
vars := measure(nvars, "variable")
vals := measure(nvals, "value")
rhs0 := rhs[0]
diff --git a/src/go/types/signature.go b/src/go/types/signature.go
index 8f89e93..f174516 100644
--- a/src/go/types/signature.go
+++ b/src/go/types/signature.go
@@ -112,7 +112,8 @@
// - the receiver specification acts as local declaration for its type parameters, which may be blank
_, rname, rparams := check.unpackRecv(recvPar.List[0].Type, true)
if len(rparams) > 0 {
- sig.rparams = bindTParams(check.declareTypeParams(nil, rparams))
+ tparams := check.declareTypeParams(nil, rparams)
+ sig.rparams = bindTParams(tparams)
// Blank identifiers don't get declared, so naive type-checking of the
// receiver type expression would fail in Checker.collectParams below,
// when Checker.ident cannot resolve the _ to a type.
@@ -122,11 +123,10 @@
// lookup in the scope.
for i, p := range rparams {
if p.Name == "_" {
- tpar := sig.rparams.At(i)
if check.recvTParamMap == nil {
check.recvTParamMap = make(map[*ast.Ident]*TypeParam)
}
- check.recvTParamMap[p] = tpar
+ check.recvTParamMap[p] = tparams[i]
}
}
// determine receiver type to get its type parameters
@@ -142,22 +142,23 @@
}
}
// provide type parameter bounds
- // - only do this if we have the right number (otherwise an error is reported elsewhere)
- if sig.RecvTypeParams().Len() == len(recvTParams) {
- // We have a list of *TypeNames but we need a list of Types.
- list := make([]Type, sig.RecvTypeParams().Len())
- for i, t := range sig.RecvTypeParams().list() {
- list[i] = t
- check.mono.recordCanon(t, recvTParams[i])
+ if len(tparams) == len(recvTParams) {
+ smap := makeRenameMap(recvTParams, tparams)
+ for i, tpar := range tparams {
+ recvTPar := recvTParams[i]
+ check.mono.recordCanon(tpar, recvTPar)
+ // recvTPar.bound is (possibly) parameterized in the context of the
+ // receiver type declaration. Substitute parameters for the current
+ // context.
+ tpar.bound = check.subst(tpar.obj.pos, recvTPar.bound, smap, nil)
}
- smap := makeSubstMap(recvTParams, list)
- for i, tpar := range sig.RecvTypeParams().list() {
- bound := recvTParams[i].bound
- // bound is (possibly) parameterized in the context of the
- // receiver type declaration. Substitute parameters for the
- // current context.
- tpar.bound = check.subst(tpar.obj.pos, bound, smap, nil)
- }
+ } else if len(tparams) < len(recvTParams) {
+ // Reporting an error here is a stop-gap measure to avoid crashes in the
+ // compiler when a type parameter/argument cannot be inferred later. It
+ // may lead to follow-on errors (see issues #51339, #51343).
+ // TODO(gri) find a better solution
+ got := measure(len(tparams), "type parameter")
+ check.errorf(recvPar, _BadRecv, "got %s, but receiver base type declares %d", got, len(recvTParams))
}
}
}
diff --git a/src/go/types/testdata/fixedbugs/issue51339.go2 b/src/go/types/testdata/fixedbugs/issue51339.go2
new file mode 100644
index 0000000..6803c44
--- /dev/null
+++ b/src/go/types/testdata/fixedbugs/issue51339.go2
@@ -0,0 +1,16 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file is tested when running "go test -run Manual"
+// without source arguments. Use for one-off debugging.
+
+package p
+
+type T[P any, B *P] struct{}
+
+func (T /* ERROR cannot use generic type */ ) m0() {}
+func (/* ERROR got 1 type parameter, but receiver base type declares 2 */ T[_]) m1() {}
+func (T[_, _]) m2() {}
+// TODO(gri) this error is unfortunate (issue #51343)
+func (T /* ERROR got 3 arguments but 2 type parameters */ [_, _, _]) m3() {}
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