feat: params.ExtraPayloadGetter.SetOnChainConfig() + Rules equiv

params/config.libevm.go

@@ -158,6 +158,12 @@ func (ExtraPayloadGetter[C, R]) PointerFromChainConfig(c *ChainConfig) *C {
 	return pseudo.MustPointerTo[C](c.extraPayload()).Value.Get()
 }
 
+// SetOnChainConfig sets the ChainConfig's extra payload. It is equivalent to
+// `*e.PointerFromChainConfig(cc) = val`.
+func (e ExtraPayloadGetter[C, R]) SetOnChainConfig(cc *ChainConfig, val C) {
+	*e.PointerFromChainConfig(cc) = val
+}
+
 // hooksFromChainConfig is equivalent to FromChainConfig(), but returns an
 // interface instead of the concrete type implementing it; this allows it to be
 // used in non-generic code.
@@ -176,6 +182,12 @@ func (ExtraPayloadGetter[C, R]) PointerFromRules(r *Rules) *R {
 	return pseudo.MustPointerTo[R](r.extraPayload()).Value.Get()
 }
 
+// SetOnRules sets the Rules' extra payload. It is equivalent to
+// `*e.PointerFromRules(r) = val`.
+func (e ExtraPayloadGetter[C, R]) SetOnRules(r *Rules, val R) {
+	*e.PointerFromRules(r) = val
+}
+
 // hooksFromRules is the [RulesHooks] equivalent of hooksFromChainConfig().
 func (e ExtraPayloadGetter[C, R]) hooksFromRules(r *Rules) RulesHooks {
 	return e.FromRules(r)

params/config.libevm_test.go

@@ -162,11 +162,11 @@ func TestModificationOfZeroExtras(t *testing.T) {
 	assertRulesExtra(t, rulesExtra{X: pi}, "after setting via pointer field")
 
 	ccReplace := ccExtra{X: 142857}
-	*getter.PointerFromChainConfig(config) = ccReplace
+	getter.SetOnChainConfig(config, ccReplace)
 	assertChainConfigExtra(t, ccReplace, "after replacement of entire extra via `*pointer = x`")
 
 	rulesReplace := rulesExtra{X: 18101986}
-	*getter.PointerFromRules(rules) = rulesReplace
+	getter.SetOnRules(rules, rulesReplace)
 	assertRulesExtra(t, rulesReplace, "after replacement of entire extra via `*pointer = x`")
 
 	if t.Failed() {