go/types: revert "no 'declared but not used' errors for invalid var d…

…ecls" This reverts commit CL 289712 (afd67f3). It breaks x/tools tests, and those tests highlight that perhaps I didn't think through the repercussions of this change as much as I should have. Fixes #44316 Change-Id: I5db39b4e2a3714131aa22423abfe0f34a0376192 Reviewed-on: https://go-review.googlesource.com/c/go/+/292751 Reviewed-by: Matthew Dempsky <[email protected]> Trust: Robert Findley <[email protected]> Run-TryBot: Robert Findley <[email protected]> TryBot-Result: Go Bot <[email protected]>
cloudflare · Feb 17, 2021 · 2f0da6d · 2f0da6d
1 parent 70c37ee
commit 2f0da6d
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Showing 3 changed files with 1 addition and 28 deletions.
diff --git a/src/go/types/assignments.go b/src/go/types/assignments.go
@@ -120,7 +120,6 @@ func (check *Checker) initVar(lhs *Var, x *operand, context string) Type {
  if lhs.typ == nil {
  lhs.typ = Typ[Invalid]
  }
- lhs.used = true
  return nil
  }
 

diff --git a/src/go/types/decl.go b/src/go/types/decl.go
@@ -504,20 +504,6 @@ func (check *Checker) constDecl(obj *Const, typ, init ast.Expr, inherited bool)
 func (check *Checker) varDecl(obj *Var, lhs []*Var, typ, init ast.Expr) {
  assert(obj.typ == nil)
 
- // If we have undefined variable types due to errors,
- // mark variables as used to avoid follow-on errors.
- // Matches compiler behavior.
- defer func() {
- if obj.typ == Typ[Invalid] {
- obj.used = true
- }
- for _, lhs := range lhs {
- if lhs.typ == Typ[Invalid] {
- lhs.used = true
- }
- }
- }()
-
  // determine type, if any
  if typ != nil {
  obj.typ = check.typ(typ)

diff --git a/src/go/types/testdata/vardecl.src b/src/go/types/testdata/vardecl.src
@@ -158,18 +158,6 @@ func _() {
  }
 }
 
-
-// Invalid variable declarations must not lead to "declared but not used errors".
-func _() {
- var a x // ERROR undeclared name: x
- var b = x // ERROR undeclared name: x
- var c int = x // ERROR undeclared name: x
- var d, e, f x /* ERROR x */ /* ERROR x */ /* ERROR x */
- var g, h, i = x /* ERROR x */, x /* ERROR x */, x /* ERROR x */
- var j, k, l float32 = x /* ERROR x */, x /* ERROR x */, x /* ERROR x */
- // but no "declared but not used" errors
-}
-
 // Invalid (unused) expressions must not lead to spurious "declared but not used errors"
 func _() {
  var a, b, c int
@@ -215,4 +203,4 @@ func _() {
  _, _, _ = x, y, z
 }
 
-// TODO(gri) consolidate other var decl checks in this file
+// TODO(gri) consolidate other var decl checks in this file