cgen: fix fixed array init with `it` (#14251)

vlib/v/gen/c/array.v

@@ -5,7 +5,7 @@ module c
 import strings
 import v.ast
 
-fn (mut g Gen) array_init(node ast.ArrayInit) {
+fn (mut g Gen) array_init(node ast.ArrayInit, var_name string) {
 	array_type := g.unwrap(node.typ)
 	mut array_styp := ''
 	elem_type := g.unwrap(node.elem_type)
@@ -24,10 +24,10 @@ fn (mut g Gen) array_init(node ast.ArrayInit) {
 	}
 	len := node.exprs.len
 	if array_type.unaliased_sym.kind == .array_fixed {
-		g.fixed_array_init(node, array_type)
+		g.fixed_array_init(node, array_type, var_name)
 	} else if len == 0 {
 		// `[]int{len: 6, cap:10, init:22}`
-		g.array_init_with_fields(node, elem_type, is_amp, shared_styp)
+		g.array_init_with_fields(node, elem_type, is_amp, shared_styp, var_name)
 	} else {
 		// `[1, 2, 3]`
 		elem_styp := g.typ(elem_type.typ)
@@ -70,17 +70,24 @@ fn (mut g Gen) array_init(node ast.ArrayInit) {
 	}
 }
 
-fn (mut g Gen) fixed_array_init(node ast.ArrayInit, array_type Type) {
+fn (mut g Gen) fixed_array_init(node ast.ArrayInit, array_type Type, var_name string) {
 	if node.has_it {
 		g.inside_lambda = true
-		tmp := g.new_tmp_var()
+		mut tmp := g.new_tmp_var()
-		mut s := g.go_before_stmt(0)
+		mut s := ''
+		if var_name.len != 0 {
+			tmp = var_name
+		} else {
+			s = g.go_before_stmt(0)
+		}
 		s_ends_with_ln := s.ends_with('\n')
 		s = s.trim_space()
 		ret_typ := g.typ(node.typ)
 		elem_typ := g.typ(node.elem_type)
 		g.empty_line = true
+		if var_name.len == 0 {
 			g.write('$ret_typ $tmp =')
+		}
 		g.write('{')
 		if node.has_val {
 			for i, expr in node.exprs {
@@ -117,12 +124,14 @@ fn (mut g Gen) fixed_array_init(node ast.ArrayInit, array_type Type) {
 		g.writeln('}')
 		g.indent--
 		g.writeln('}')
+		if var_name.len == 0 {
 			if s_ends_with_ln {
 				g.writeln(s)
 			} else {
 				g.write(s)
 			}
 			g.write(tmp)
+		}
 		g.inside_lambda = false
 		return
 	}
@@ -166,21 +175,28 @@ fn (mut g Gen) fixed_array_init(node ast.ArrayInit, array_type Type) {
 }
 
 // `[]int{len: 6, cap: 10, init: it * it}`
-fn (mut g Gen) array_init_with_fields(node ast.ArrayInit, elem_type Type, is_amp bool, shared_styp string) {
+fn (mut g Gen) array_init_with_fields(node ast.ArrayInit, elem_type Type, is_amp bool, shared_styp string, var_name string) {
 	elem_styp := g.typ(elem_type.typ)
 	noscan := g.check_noscan(elem_type.typ)
 	is_default_array := elem_type.unaliased_sym.kind == .array && node.has_default
 	is_default_map := elem_type.unaliased_sym.kind == .map && node.has_default
 	if node.has_it { // []int{len: 6, init: it * it} when variable it is used in init expression
 		g.inside_lambda = true
-		tmp := g.new_tmp_var()
+		mut tmp := g.new_tmp_var()
-		mut s := g.go_before_stmt(0)
+		mut s := ''
+		if var_name.len != 0 {
+			tmp = var_name
+		} else {
+			s = g.go_before_stmt(0)
+		}
 		s_ends_with_ln := s.ends_with('\n')
 		s = s.trim_space()
 		ret_typ := g.typ(node.typ)
 		elem_typ := g.typ(node.elem_type)
 		g.empty_line = true
+		if var_name.len == 0 {
 			g.write('$ret_typ $tmp =')
+		}
 		if is_default_array {
 			g.write('__new_array_with_array_default${noscan}(')
 		} else if is_default_map {
@@ -238,12 +254,14 @@ fn (mut g Gen) array_init_with_fields(node ast.ArrayInit, elem_type Type, is_amp
 		g.writeln('}')
 		g.indent--
 		g.writeln('}')
+		if var_name.len == 0 {
 			if s_ends_with_ln {
 				g.writeln(s)
 			} else {
 				g.write(s)
 			}
 			g.write(tmp)
+		}
 		g.inside_lambda = false
 		return
 	}

vlib/v/gen/c/assign.v

@@ -440,7 +440,7 @@ fn (mut g Gen) gen_assign_stmt(node_ ast.AssignStmt) {
 				} else if is_decl {
 					if is_fixed_array_init && !has_val {
 						if val is ast.ArrayInit {
-							g.array_init(val)
+							g.array_init(val, ident.name)
 						} else {
 							g.write('{0}')
 						}
@@ -451,7 +451,11 @@ fn (mut g Gen) gen_assign_stmt(node_ ast.AssignStmt) {
 						if val.is_auto_deref_var() {
 							g.write('*')
 						}
+						if val is ast.ArrayInit {
+							g.array_init(val, ident.name)
+						} else {
 							g.expr(val)
+						}
 						if is_auto_heap {
 							g.write('))')
 						}

vlib/v/gen/c/cgen.v

@@ -2879,7 +2879,7 @@ fn (mut g Gen) expr(node_ ast.Expr) {
 			g.expr(node.expr)
 		}
 		ast.ArrayInit {
-			g.array_init(node)
+			g.array_init(node, '')
 		}
 		ast.AsCast {
 			g.as_cast(node)

vlib/v/tests/array_with_it_test.v

@@ -1,6 +1,17 @@
 fn test_array_with_it() {
 	assert [0, 1, 2, 3, 4, 5]! == [6]int{init: it}
+	a1 := [6]int{init: it}
+	assert a1 == [0, 1, 2, 3, 4, 5]!
+
 	assert [0, 1, 4, 9, 16, 25] == []int{len: 6, init: it * it}
+	a2 := []int{len: 6, init: it * it}
+	assert a2 == [0, 1, 4, 9, 16, 25]
+
 	assert [1, 2, 3, 4, 5] == []int{len: 5, init: it + 1}
+	a3 := []int{len: 5, init: it + 1}
+	assert a3 == [1, 2, 3, 4, 5]
+
 	assert [5, 4, 3, 2, 1] == []int{len: 5, init: 5 - it}
+	a4 := []int{len: 5, init: 5 - it}
+	assert a4 == [5, 4, 3, 2, 1]
 }