diff --git a/src/cmd/compile/internal/types2/expr.go b/src/cmd/compile/internal/types2/expr.go
index 17e120f9488..40d6e5da695 100644
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -943,9 +943,10 @@ func (check *Checker) shift(x, y *operand, e syntax.Expr, op syntax.Operator) {
 
 	// Check that constants are representable by uint, but do not convert them
 	// (see also issue #47243).
+	var yval constant.Value
 	if y.mode == constant_ {
 		// Provide a good error message for negative shift counts.
-		yval := constant.ToInt(y.val) // consider -1, 1.0, but not -1.1
+		yval = constant.ToInt(y.val) // consider -1, 1.0, but not -1.1
 		if yval.Kind() == constant.Int && constant.Sign(yval) < 0 {
 			check.errorf(y, InvalidShiftCount, invalidOp+"negative shift count %s", y)
 			x.mode = invalid
@@ -998,7 +999,7 @@ func (check *Checker) shift(x, y *operand, e syntax.Expr, op syntax.Operator) {
 			}
 			// rhs must be within reasonable bounds in constant shifts
 			const shiftBound = 1023 - 1 + 52 // so we can express smallestFloat64 (see issue #44057)
-			s, ok := constant.Uint64Val(y.val)
+			s, ok := constant.Uint64Val(yval)
 			if !ok || s > shiftBound {
 				check.errorf(y, InvalidShiftCount, invalidOp+"invalid shift count %s", y)
 				x.mode = invalid
diff --git a/src/go/types/expr.go b/src/go/types/expr.go
index f11632fd6b5..da9cd67826f 100644
--- a/src/go/types/expr.go
+++ b/src/go/types/expr.go
@@ -920,9 +920,10 @@ func (check *Checker) shift(x, y *operand, e ast.Expr, op token.Token) {
 
 	// Check that constants are representable by uint, but do not convert them
 	// (see also issue #47243).
+	var yval constant.Value
 	if y.mode == constant_ {
 		// Provide a good error message for negative shift counts.
-		yval := constant.ToInt(y.val) // consider -1, 1.0, but not -1.1
+		yval = constant.ToInt(y.val) // consider -1, 1.0, but not -1.1
 		if yval.Kind() == constant.Int && constant.Sign(yval) < 0 {
 			check.errorf(y, InvalidShiftCount, invalidOp+"negative shift count %s", y)
 			x.mode = invalid
@@ -975,7 +976,7 @@ func (check *Checker) shift(x, y *operand, e ast.Expr, op token.Token) {
 			}
 			// rhs must be within reasonable bounds in constant shifts
 			const shiftBound = 1023 - 1 + 52 // so we can express smallestFloat64 (see issue #44057)
-			s, ok := constant.Uint64Val(y.val)
+			s, ok := constant.Uint64Val(yval)
 			if !ok || s > shiftBound {
 				check.errorf(y, InvalidShiftCount, invalidOp+"invalid shift count %s", y)
 				x.mode = invalid
diff --git a/src/internal/types/testdata/fixedbugs/issue56425.go b/src/internal/types/testdata/fixedbugs/issue56425.go
new file mode 100644
index 00000000000..d85733faaac
--- /dev/null
+++ b/src/internal/types/testdata/fixedbugs/issue56425.go
@@ -0,0 +1,8 @@
+// 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.
+
+package p
+
+const s float32 = 0
+var _ = 0 << s