cgen: remove double string cloning (#23331)

Author: felipensp

vlib/v/gen/c/array.v

@@ -46,7 +46,7 @@ fn (mut g Gen) array_init(node ast.ArrayInit, var_name string) {
 		}
 		for i, expr in node.exprs {
 			if node.expr_types[i] == ast.string_type
-				&& expr !in [ast.StringLiteral, ast.StringInterLiteral] {
+				&& expr !in [ast.IndexExpr, ast.CallExpr, ast.StringLiteral, ast.StringInterLiteral, ast.InfixExpr] {
 				g.write('string_clone(')
 				g.expr(expr)
 				g.write(')')
@@ -1035,12 +1035,14 @@ fn (mut g Gen) gen_array_insert(node ast.CallExpr) {
 		g.expr(node.args[1].expr)
 		g.write('.len)')
 	} else {
+		needs_clone := left_info.elem_type == ast.string_type
+			&& node.args[1].expr !in [ast.IndexExpr, ast.CallExpr, ast.StringLiteral, ast.StringInterLiteral, ast.InfixExpr]
 		g.write(', &(${elem_type_str}[]){')
-		if left_info.elem_type == ast.string_type {
+		if needs_clone {
 			g.write('string_clone(')
 		}
 		g.expr_with_cast(node.args[1].expr, node.args[1].typ, left_info.elem_type)
-		if left_info.elem_type == ast.string_type {
+		if needs_clone {
 			g.write(')')
 		}
 		g.write('})')

vlib/v/gen/c/assert.v

@@ -229,7 +229,8 @@ fn (mut g Gen) gen_assert_single_expr(expr ast.Expr, typ ast.Type) {
 		}
 		else {
 			mut should_clone := true
-			if typ == ast.string_type && expr is ast.StringLiteral {
+			if typ == ast.string_type
+				&& expr in [ast.IndexExpr, ast.CallExpr, ast.StringLiteral, ast.StringInterLiteral] {
 				should_clone = false
 			}
 			if expr is ast.CTempVar {

vlib/v/gen/c/infix.v

@@ -1054,6 +1054,7 @@ fn (mut g Gen) infix_expr_left_shift_op(node ast.InfixExpr) {
 				needs_clone := !g.is_builtin_mod
 					&& array_info.elem_type.idx() == ast.string_type_idx
 					&& array_info.elem_type.nr_muls() == 0
+					&& node.right !in [ast.StringLiteral, ast.StringInterLiteral, ast.CallExpr, ast.IndexExpr, ast.InfixExpr]
 				if needs_clone {
 					g.write('string_clone(')
 				}