From: Robert Findley <rfindley@google.com>
Date: Tue, 9 Nov 2021 19:56:39 +0000 (-0500)
Subject: go/types: don't return an array type with invalid length
X-Git-Tag: go1.18beta1~416
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=cb908f1d4dd24dad17105022df7b0e96ac1d6988;p=gostls13.git

go/types: don't return an array type with invalid length

In preparation for porting CL 361412, fix a discrepancy in go/types,
where [-1]T is returned for an array type with invalid length.

Change-Id: Ia32f5b66c9c561ccf0c32af1922fc4690c66dbc3
Reviewed-on: https://go-review.googlesource.com/c/go/+/362738
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
---

diff --git a/src/go/types/api_test.go b/src/go/types/api_test.go
index 807bffbff6..3e10be5985 100644
--- a/src/go/types/api_test.go
+++ b/src/go/types/api_test.go
@@ -342,7 +342,7 @@ func TestTypesInfo(t *testing.T) {
 		{broken + `x2; func _() { var a, b string; type x struct {f string}; z := &x{f: a; f: b;}}`, `b`, `string`},
 		{broken + `x3; var x = panic("");`, `panic`, `func(interface{})`},
 		{`package x4; func _() { panic("") }`, `panic`, `func(interface{})`},
-		{broken + `x5; func _() { var x map[string][...]int; x = map[string][...]int{"": {1,2,3}} }`, `x`, `map[string][-1]int`},
+		{broken + `x5; func _() { var x map[string][...]int; x = map[string][...]int{"": {1,2,3}} }`, `x`, `map[string]invalid type`},
 
 		// parameterized functions
 		{genericPkg + `p0; func f[T any](T) {}; var _ = f[int]`, `f`, `func[T interface{}](T)`},
diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
index e1d942a5c6..cc2bd62209 100644
--- a/src/go/types/typexpr.go
+++ b/src/go/types/typexpr.go
@@ -271,18 +271,20 @@ func (check *Checker) typInternal(e0 ast.Expr, def *Named) (T Type) {
 		return check.definedType(e.X, def)
 
 	case *ast.ArrayType:
-		if e.Len != nil {
-			typ := new(Array)
+		if e.Len == nil {
+			typ := new(Slice)
 			def.setUnderlying(typ)
-			typ.len = check.arrayLength(e.Len)
 			typ.elem = check.varType(e.Elt)
 			return typ
 		}
 
-		typ := new(Slice)
+		typ := new(Array)
 		def.setUnderlying(typ)
+		typ.len = check.arrayLength(e.Len)
 		typ.elem = check.varType(e.Elt)
-		return typ
+		if typ.len >= 0 {
+			return typ
+		}
 
 	case *ast.Ellipsis:
 		// dots are handled explicitly where they are legal