From 27f637a8dcb84709477cfe02f302e4cec57a40ab Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Mon, 20 Jan 2025 12:28:19 -0300
Subject: [PATCH] checker: simplify unwrap nested selector fix (#23526)

---
 vlib/v/ast/ast.v                              |  5 +-
 vlib/v/ast/scope.v                            | 10 ----
 vlib/v/checker/checker.v                      | 32 ++++---------
 .../option_generic_selector_unwrap_test.v     | 33 +++++++++++++
 .../option_selector_nested_unwrap_test.v      | 46 +++++++++++++++++++
 5 files changed, 91 insertions(+), 35 deletions(-)
 create mode 100644 vlib/v/tests/options/option_generic_selector_unwrap_test.v
 create mode 100644 vlib/v/tests/options/option_selector_nested_unwrap_test.v

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 67ff7914e4..8936dadd39 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -925,9 +925,8 @@ pub:
 	name        string
 	pos         token.Pos
 	typ         Type
-	orig_type   Type // original sumtype type; 0 if it's not a sumtype
-pub mut:
-	smartcasts []Type // nested sum types require nested smart casting, for that a list of types is needed
+	orig_type   Type   // original sumtype type; 0 if it's not a sumtype
+	smartcasts  []Type // nested sum types require nested smart casting, for that a list of types is needed
 	// TODO: move this to a real docs site later
 	// 10 <- original type (orig_type)
 	//   [11, 12, 13] <- cast order (smartcasts)
diff --git a/vlib/v/ast/scope.v b/vlib/v/ast/scope.v
index 9980befaca..127240c624 100644
--- a/vlib/v/ast/scope.v
+++ b/vlib/v/ast/scope.v
@@ -157,16 +157,6 @@ pub fn (mut s Scope) register_struct_field(name string, field ScopeStructField)
 	s.struct_fields[name] = field
 }
 
-pub fn (mut s Scope) register_or_update_struct_field(name string, field ScopeStructField) {
-	if mut f := s.struct_fields[name] {
-		if f.struct_type == field.struct_type && f.name == field.name {
-			s.struct_fields[name].smartcasts = field.smartcasts
-			return
-		}
-	}
-	s.struct_fields[name] = field
-}
-
 pub fn (mut s Scope) register(obj ScopeObject) {
 	if !(obj.name == '_' || obj.name in s.objects) {
 		s.objects[obj.name] = obj
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 91fbb36485..532bede4f3 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -4286,33 +4286,21 @@ fn (mut c Checker) smartcast(mut expr ast.Expr, cur_type ast.Type, to_type_ ast.
 					orig_type = field.typ
 				}
 			}
-			mut nested_unwrap := false
-			if mut field := scope.find_struct_field(expr.expr.str(), expr.expr_type, expr.field_name) {
+			expr_str := expr.expr.str()
+			if mut field := scope.find_struct_field(expr_str, expr.expr_type, expr.field_name) {
 				smartcasts << field.smartcasts
-				nested_unwrap = smartcasts.len > 1
 			}
 			// smartcast either if the value is immutable or if the mut argument is explicitly given
 			if !is_mut || expr.is_mut || is_option_unwrap || orig_type.has_flag(.option) {
 				smartcasts << to_type
-				if nested_unwrap {
-					scope.register_or_update_struct_field(expr.expr.str(), ast.ScopeStructField{
-						struct_type: expr.expr_type
-						name:        expr.field_name
-						typ:         cur_type
-						smartcasts:  smartcasts
-						pos:         expr.pos
-						orig_type:   orig_type
-					})
-				} else {
-					scope.register_struct_field(expr.expr.str(), ast.ScopeStructField{
-						struct_type: expr.expr_type
-						name:        expr.field_name
-						typ:         cur_type
-						smartcasts:  smartcasts
-						pos:         expr.pos
-						orig_type:   orig_type
-					})
-				}
+				scope.register_struct_field(expr_str, ast.ScopeStructField{
+					struct_type: expr.expr_type
+					name:        expr.field_name
+					typ:         cur_type
+					smartcasts:  smartcasts
+					pos:         expr.pos
+					orig_type:   orig_type
+				})
 			} else {
 				c.smartcast_mut_pos = expr.pos
 			}
diff --git a/vlib/v/tests/options/option_generic_selector_unwrap_test.v b/vlib/v/tests/options/option_generic_selector_unwrap_test.v
new file mode 100644
index 0000000000..8da51ebf76
--- /dev/null
+++ b/vlib/v/tests/options/option_generic_selector_unwrap_test.v
@@ -0,0 +1,33 @@
+type SumType = int | string | f64
+
+struct Foo[T] {
+	field ?SumType
+}
+
+fn t[T](val Foo[T]) {
+	if val.field != none {
+		if val.field is string {
+			dump(val.field)
+			assert val.field == 'foo'
+		} else if val.field is int {
+			dump(val.field)
+			assert val.field == 1
+		} else if val.field is f64 {
+			dump(val.field)
+			assert val.field == 1.23
+		}
+	} else {
+		dump(val.field)
+		assert val.field == none
+	}
+}
+
+fn test_main() {
+	t(Foo[int]{})
+	t(Foo[string]{})
+	t(Foo[f64]{})
+
+	t(Foo[int]{ field: 1 })
+	t(Foo[string]{ field: 'foo' })
+	t(Foo[f64]{ field: 1.23 })
+}
diff --git a/vlib/v/tests/options/option_selector_nested_unwrap_test.v b/vlib/v/tests/options/option_selector_nested_unwrap_test.v
new file mode 100644
index 0000000000..466578db3a
--- /dev/null
+++ b/vlib/v/tests/options/option_selector_nested_unwrap_test.v
@@ -0,0 +1,46 @@
+module main
+
+type Foo = string | int | f32
+
+struct Svc {
+mut:
+	log ?Foo
+}
+
+fn t(v string) !string {
+	return v
+}
+
+fn Svc.init(log ?Foo) Svc {
+	mut svc := Svc{
+		log: log
+	}
+	if svc.log != none {
+		if svc.log is string {
+			assert svc.log.str() == 'foo'
+			_ := t(svc.log) or { panic(err) }
+		} else {
+			assert false
+		}
+		assert true
+	}
+	return svc
+}
+
+struct CSvc {
+	Svc
+pub mut:
+	log ?Foo
+}
+
+pub fn CSvc.init(log ?Foo) CSvc {
+	mut c := CSvc{
+		log: log
+	}
+	c.Svc = Svc.init(log)
+	return c
+}
+
+fn test_main() {
+	CSvc.init('foo')
+}