diff --git a/src/go/types/builtins.go b/src/go/types/builtins.go
index cc50f677c7..a445ebf1c6 100644
--- a/src/go/types/builtins.go
+++ b/src/go/types/builtins.go
@@ -441,10 +441,13 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 			check.errorf(call.Pos(), "%v expects %d or %d arguments; found %d", call, min, min+1, nargs)
 			return
 		}
+		types := []Type{T}
 		var sizes []int64 // constant integer arguments, if any
 		for _, arg := range call.Args[1:] {
-			if s, ok := check.index(arg, -1); ok && s >= 0 {
-				sizes = append(sizes, s)
+			typ, size := check.index(arg, -1) // ok to continue with typ == Typ[Invalid]
+			types = append(types, typ)
+			if size >= 0 {
+				sizes = append(sizes, size)
 			}
 		}
 		if len(sizes) == 2 && sizes[0] > sizes[1] {
@@ -454,8 +457,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		x.mode = value
 		x.typ = T
 		if check.Types != nil {
-			params := [...]Type{T, Typ[Int], Typ[Int]}
-			check.recordBuiltinType(call.Fun, makeSig(x.typ, params[:nargs]...))
+			check.recordBuiltinType(call.Fun, makeSig(x.typ, types...))
 		}
 
 	case _New:
diff --git a/src/go/types/builtins_test.go b/src/go/types/builtins_test.go
index ac0145ea87..cfd19d5e28 100644
--- a/src/go/types/builtins_test.go
+++ b/src/go/types/builtins_test.go
@@ -79,14 +79,13 @@ var builtinCalls = []struct {
 	{"make", `var    c int; _ = make([]int, 0, c)`, `func([]int, int, int) []int`},
 	{"make", `var l, c int; _ = make([]int, l, c)`, `func([]int, int, int) []int`},
 
-	// TODO(gri) enable once the issue is fixed
 	// issue #37393
-	// {"make", `                _ = make([]int       , 0   )`, `func([]int, int) []int`},
-	// {"make", `var l    byte ; _ = make([]int8      , l   )`, `func([]int8, byte) []int8`},
-	// {"make", `                _ = make([]int16     , 0, 0)`, `func([]int16, int, int) []int16`},
-	// {"make", `var l    int16; _ = make([]string    , l, 0)`, `func([]string, int16, int) []string`},
-	// {"make", `var    c int32; _ = make([]float64   , 0, c)`, `func([]float64, int, int32) []float64`},
-	// {"make", `var l, c uint ; _ = make([]complex128, l, c)`, `func([]complex128, uint, uint) []complex128`},
+	{"make", `                _ = make([]int       , 0   )`, `func([]int, int) []int`},
+	{"make", `var l    byte ; _ = make([]int8      , l   )`, `func([]int8, byte) []int8`},
+	{"make", `                _ = make([]int16     , 0, 0)`, `func([]int16, int, int) []int16`},
+	{"make", `var l    int16; _ = make([]string    , l, 0)`, `func([]string, int16, int) []string`},
+	{"make", `var    c int32; _ = make([]float64   , 0, c)`, `func([]float64, int, int32) []float64`},
+	{"make", `var l, c uint ; _ = make([]complex128, l, c)`, `func([]complex128, uint, uint) []complex128`},
 
 	{"new", `_ = new(int)`, `func(int) *int`},
 	{"new", `type T struct{}; _ = new(T)`, `func(p.T) *p.T`},
diff --git a/src/go/types/expr.go b/src/go/types/expr.go
index d49ccdf67e..165778c2f7 100644
--- a/src/go/types/expr.go
+++ b/src/go/types/expr.go
@@ -868,8 +868,12 @@ func (check *Checker) binary(x *operand, e *ast.BinaryExpr, lhs, rhs ast.Expr, o
 
 // index checks an index expression for validity.
 // If max >= 0, it is the upper bound for index.
-// If index is valid and the result i >= 0, then i is the constant value of index.
-func (check *Checker) index(index ast.Expr, max int64) (i int64, valid bool) {
+// If the result typ is != Typ[Invalid], index is valid and typ is its (possibly named) integer type.
+// If the result val >= 0, index is valid and val is its constant int value.
+func (check *Checker) index(index ast.Expr, max int64) (typ Type, val int64) {
+	typ = Typ[Invalid]
+	val = -1
+
 	var x operand
 	check.expr(&x, index)
 	if x.mode == invalid {
@@ -888,22 +892,24 @@ func (check *Checker) index(index ast.Expr, max int64) (i int64, valid bool) {
 		return
 	}
 
-	// a constant index i must be in bounds
-	if x.mode == constant_ {
-		if constant.Sign(x.val) < 0 {
-			check.invalidArg(x.pos(), "index %s must not be negative", &x)
-			return
-		}
-		i, valid = constant.Int64Val(constant.ToInt(x.val))
-		if !valid || max >= 0 && i >= max {
-			check.errorf(x.pos(), "index %s is out of bounds", &x)
-			return i, false
-		}
-		// 0 <= i [ && i < max ]
-		return i, true
+	if x.mode != constant_ {
+		return x.typ, -1
 	}
 
-	return -1, true
+	// a constant index i must be in bounds
+	if constant.Sign(x.val) < 0 {
+		check.invalidArg(x.pos(), "index %s must not be negative", &x)
+		return
+	}
+
+	v, valid := constant.Int64Val(constant.ToInt(x.val))
+	if !valid || max >= 0 && v >= max {
+		check.errorf(x.pos(), "index %s is out of bounds", &x)
+		return
+	}
+
+	// 0 <= v [ && v < max ]
+	return Typ[Int], v
 }
 
 // indexElts checks the elements (elts) of an array or slice composite literal
@@ -919,7 +925,7 @@ func (check *Checker) indexedElts(elts []ast.Expr, typ Type, length int64) int64
 		validIndex := false
 		eval := e
 		if kv, _ := e.(*ast.KeyValueExpr); kv != nil {
-			if i, ok := check.index(kv.Key, length); ok {
+			if typ, i := check.index(kv.Key, length); typ != Typ[Invalid] {
 				if i >= 0 {
 					index = i
 					validIndex = true
@@ -1411,8 +1417,8 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
 				if length >= 0 {
 					max = length + 1
 				}
-				if t, ok := check.index(expr, max); ok && t >= 0 {
-					x = t
+				if _, v := check.index(expr, max); v >= 0 {
+					x = v
 				}
 			case i == 0:
 				// default is 0 for the first index