diff options
Diffstat (limited to 'go')
| -rw-r--r-- | go/types/stmt.go | 9 | ||||
| -rw-r--r-- | go/types/testdata/stmt0.src | 1 |
2 files changed, 9 insertions, 1 deletions
diff --git a/go/types/stmt.go b/go/types/stmt.go index fa60f64..3917336 100644 --- a/go/types/stmt.go +++ b/go/types/stmt.go @@ -456,7 +456,14 @@ func (check *Checker) stmt(ctxt stmtContext, s ast.Stmt) { check.invalidAST(s.Pos(), "incorrect form of type switch guard") return } - check.recordDef(lhs, nil) // lhs variable is implicitly declared in each cause clause + + if lhs.Name == "_" { + // _ := x.(type) is an invalid short variable declaration + check.softErrorf(lhs.Pos(), "no new variable on left side of :=") + lhs = nil // avoid declared but not used error below + } else { + check.recordDef(lhs, nil) // lhs variable is implicitly declared in each cause clause + } rhs = guard.Rhs[0] diff --git a/go/types/testdata/stmt0.src b/go/types/testdata/stmt0.src index 4c84036..073e83b 100644 --- a/go/types/testdata/stmt0.src +++ b/go/types/testdata/stmt0.src @@ -540,6 +540,7 @@ func typeswitches() { } switch x /* ERROR "declared but not used" */ := x.(type) {} + switch _ /* ERROR "no new variable on left side of :=" */ := x.(type) {} switch x := x.(type) { case int: |