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diff --git a/‎src/go/types/expr.go‎
Lines changed: 3 additions & 0 deletions b/‎src/go/types/expr.go‎
Lines changed: 3 additions & 0 deletions
diff --git a/‎src/go/types/predicates.go‎
Lines changed: 3 additions & 1 deletion b/‎src/go/types/predicates.go‎
Lines changed: 3 additions & 1 deletion
diff --git a/‎src/go/types/type.go‎
Lines changed: 3 additions & 0 deletions b/‎src/go/types/type.go‎
Lines changed: 3 additions & 0 deletions
@@ -679,6 +679,9 @@ func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, const
 	case *TypeParam:
 		// TODO(gri) review this code - doesn't look quite right
 		ok := u.underIs(func(t Type) bool {
+			if t == nil {
+				return false
+			}
 			target, _, _ := check.implicitTypeAndValue(x, t)
 			return target != nil
 		})
 
@@ -149,7 +149,9 @@ func hasNil(t Type) bool {
 	case *Slice, *Pointer, *Signature, *Interface, *Map, *Chan:
 		return true
 	case *TypeParam:
-		return u.underIs(hasNil)
+		return u.underIs(func(u Type) bool {
+			return u != nil && hasNil(u)
+		})
 	}
 	return false
 }
 
@@ -65,6 +65,9 @@ func match(x, y Type) Type {
 func structuralType(typ Type) Type {
 	var su Type
 	if underIs(typ, func(u Type) bool {
+		if u == nil {
+			return false
+		}
 		if su != nil {
 			u = match(su, u)
 			if u == nil {
Original file line number	Diff line number	Diff line change
`@@ -149,7 +149,9 @@ func hasNil(t Type) bool {`
`149`	`149`	`case Slice, Pointer, Signature, Interface, Map, Chan:`
`150`	`150`	`return true`
`151`	`151`	`case *TypeParam:`
`152`		`- return u.underIs(hasNil)`
	`152`	`+ return u.underIs(func(u Type) bool {`
	`153`	`+ return u != nil && hasNil(u)`
	`154`	`+ })`
`153`	`155`	`}`
`154`	`156`	`return false`
`155`	`157`	`}`