diff --git a/src/cmd/compile/internal/typecheck/typecheck.go b/src/cmd/compile/internal/typecheck/typecheck.go
index ab493e0caa..00dd44b96b 100644
--- a/src/cmd/compile/internal/typecheck/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@@ -596,6 +596,10 @@ func typecheck1(n ir.Node, top int) ir.Node {
 	case ir.OANDAND, ir.OOROR:
 		n := n.(*ir.LogicalExpr)
 		n.X, n.Y = Expr(n.X), Expr(n.Y)
+		if n.X.Type() == nil || n.Y.Type() == nil {
+			n.SetType(nil)
+			return n
+		}
 		// For "x == x && len(s)", it's better to report that "len(s)" (type int)
 		// can't be used with "&&" than to report that "x == x" (type untyped bool)
 		// can't be converted to int (see issue #41500).
diff --git a/test/fixedbugs/issue45804.go b/test/fixedbugs/issue45804.go
new file mode 100644
index 0000000000..28d42c8d81
--- /dev/null
+++ b/test/fixedbugs/issue45804.go
@@ -0,0 +1,19 @@
+// errorcheck
+
+// Copyright 2021 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
+
+func g() int
+func h(int)
+
+var b bool
+
+func f() {
+	did := g()
+	if !did && b { // ERROR "invalid operation"
+		h(x) // ERROR "undefined"
+	}
+}