checker: cleanup the const variable evaluate for fixed array fields o…

…f structs (#20503)

vlib/v/checker/containers.v

@@ -247,9 +247,13 @@ fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 		node.elem_type = elem_type
 	} else if node.is_fixed && node.exprs.len == 1 && node.elem_type != ast.void_type {
 		// `[50]u8`
-		mut init_expr := node.exprs[0]
-		node.typ = c.eval_array_fixed_sizes(mut init_expr, 0, node.elem_type)
-		node.elem_type = (c.table.sym(node.typ).info as ast.ArrayFixed).elem_type
+		sym := c.table.sym(node.typ)
+		if sym.info !is ast.ArrayFixed
+			|| c.array_fixed_has_unresolved_size(sym.info as ast.ArrayFixed) {
+			mut size_expr := node.exprs[0]
+			node.typ = c.eval_array_fixed_sizes(mut size_expr, 0, node.elem_type)
+			node.elem_type = (c.table.sym(node.typ).info as ast.ArrayFixed).elem_type
+		}
 		if node.has_init {
 			c.check_array_init_default_expr(mut node)
 		}
@@ -381,6 +385,26 @@ fn (mut c Checker) eval_array_fixed_sizes(mut size_expr ast.Expr, size int, elem
 	}
 }
 
+fn (mut c Checker) array_fixed_has_unresolved_size(info &ast.ArrayFixed) bool {
+	if info.size <= 0 {
+		return true
+	}
+	mut elem_type := info.elem_type
+	mut elem_sym := c.table.sym(elem_type)
+	for {
+		if mut elem_sym.info is ast.ArrayFixed {
+			if elem_sym.info.size <= 0 {
+				return true
+			}
+			elem_type = elem_sym.info.elem_type
+			elem_sym = c.table.sym(elem_type)
+		} else {
+			break
+		}
+	}
+	return false
+}
+
 fn (mut c Checker) map_init(mut node ast.MapInit) ast.Type {
 	// `map = {}`
 	if node.keys.len == 0 && node.vals.len == 0 && node.typ == 0 {

vlib/v/checker/struct.v

@@ -5,7 +5,6 @@ module checker
 import v.ast
 import v.util
 import v.token
-import v.transformer
 
 fn (mut c Checker) struct_decl(mut node ast.StructDecl) {
 	util.timing_start(@METHOD)
@@ -57,56 +56,9 @@ fn (mut c Checker) struct_decl(mut node ast.StructDecl) {
 		// Evaluate the size of the unresolved fixed array
 		for mut field in node.fields {
 			sym := c.table.sym(field.typ)
-			if sym.kind == .array_fixed {
-				info := sym.info as ast.ArrayFixed
-				if info.size > 0 {
-					continue
-				}
-				mut fixed_size := 0
-				match info.size_expr {
-					ast.Ident {
-						if mut const_field := c.table.global_scope.find_const('${c.mod}.${info.size_expr.name}') {
-							if mut const_field.expr is ast.IntegerLiteral {
-								fixed_size = const_field.expr.val.int()
-							} else if mut const_field.expr is ast.InfixExpr {
-								mut t := transformer.new_transformer_with_table(c.table,
-									c.pref)
-								folded_expr := t.infix_expr(mut const_field.expr)
-								if folded_expr is ast.IntegerLiteral {
-									fixed_size = folded_expr.val.int()
-								}
-							}
-						}
-						if fixed_size <= 0 {
-							c.error('non-constant array bound `${info.size_expr.name}`',
-								info.size_expr.pos)
-						}
-					}
-					ast.InfixExpr {
-						mut t := transformer.new_transformer_with_table(c.table, c.pref)
-						mut size_expr := unsafe { &info.size_expr }
-						folded_expr := t.infix_expr(mut size_expr)
-
-						if folded_expr is ast.IntegerLiteral {
-							fixed_size = folded_expr.val.int()
-						}
-						if fixed_size <= 0 {
-							c.error('fixed array size cannot use non-constant eval value',
-								info.size_expr.pos)
-						}
-					}
-					else {}
-				}
-				if fixed_size <= 0 {
-					c.error('fixed size cannot be zero or negative', info.size_expr.pos())
-				}
-				idx := c.table.find_or_register_array_fixed(info.elem_type, fixed_size,
-					info.size_expr, false)
-				if info.elem_type.has_flag(.generic) {
-					field.typ = ast.new_type(idx).set_flag(.generic)
-				} else {
-					field.typ = ast.new_type(idx)
-				}
+			if sym.info is ast.ArrayFixed && c.array_fixed_has_unresolved_size(sym.info) {
+				mut size_expr := unsafe { sym.info.size_expr }
+				field.typ = c.eval_array_fixed_sizes(mut size_expr, 0, sym.info.elem_type)
 				for mut symfield in struct_sym.info.fields {
 					if symfield.name == field.name {
 						symfield.typ = field.typ

vlib/v/tests/constant_array_size_test.v

@@ -9,21 +9,24 @@ fn test_consant_array_size() {
 	b = [1, 2]!
 }
 
+// for 19593
 // test const was declared below struct fixed array fields declaration
 struct Foo {
-	posts [max_posts_count]int
+	arr [width][2][width + 1]f64
 }
 
-const max_posts_count = 5
-
 fn test_const_below_at_struct_fixed_array_fields() {
 	foo := Foo{}
-	assert foo.posts == [0, 0, 0, 0, 0]!
+	assert foo.arr.len == 2
+	assert foo.arr[0].len == 2
+	assert foo.arr[0][0].len == 3
+	assert foo.arr == [[[0.0, 0.0, 0.0]!, [0.0, 0.0, 0.0]!]!,
+		[[0.0, 0.0, 0.0]!, [0.0, 0.0, 0.0]!]!]!
 }
 
 // for issue 20311
-// When using a static variable to define a fixed array size,
-// if the static variable is defined below or in another module, the size value will not be calculated correctly.
+// when using a const variable to define a fixed array size,
+// if the const variable is defined below or in another module, the size value will not be calculated correctly.
 fn test_const_below_at_fixed_array() {
 	arr := [width][2][width + 1]f64{}
 	assert arr.len == 2
@@ -33,5 +36,6 @@ fn test_const_below_at_fixed_array() {
 		[0.0, 0.0, 0.0]!]!]!
 }
 
-// Do not move this definition; it must be below `fn test_const_below_at_fixed_array()`.
+// do not move this definition,
+// it must be below `struct Foo {...}` and `fn test_const_below_at_fixed_array()`.
 const width = 2