checker, cgen: fix shared non-decl assignment (#14466)

vlib/v/checker/assign.v

@@ -224,7 +224,7 @@ pub fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 							left_type = left_type.set_nr_muls(1)
 						}
 					} else if left_type.has_flag(.shared_f) {
-						left_type = left_type.clear_flag(.shared_f)
+						left_type = left_type.clear_flag(.shared_f).deref()
 					}
 					if ident_var_info.share == .atomic_t {
 						left_type = left_type.set_flag(.atomic_f)

vlib/v/checker/containers.v

@@ -81,7 +81,11 @@ pub fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 		array_info := type_sym.array_info()
 		node.elem_type = array_info.elem_type
 		// clear optional flag incase of: `fn opt_arr ?[]int { return [] }`
-		return c.expected_type.clear_flag(.optional)
+		return if c.expected_type.has_flag(.shared_f) {
+			c.expected_type.clear_flag(.shared_f).deref()
+		} else {
+			c.expected_type
+		}.clear_flag(.optional)
 	}
 	// [1,2,3]
 	if node.exprs.len > 0 && node.elem_type == ast.void_type {

vlib/v/gen/c/assign.v

@@ -389,6 +389,9 @@ fn (mut g Gen) gen_assign_stmt(node_ ast.AssignStmt) {
 							g.write('*')
 						}
 						g.expr(left)
+						if !is_decl && var_type.has_flag(.shared_f) {
+							g.write('->val') // don't reset the mutex, just change the value
+						}
 					}
 				}
 			}
@@ -432,7 +435,6 @@ fn (mut g Gen) gen_assign_stmt(node_ ast.AssignStmt) {
 				}
 				*/
 			}
-			g.is_shared = var_type.has_flag(.shared_f)
 			if !cloned {
 				if is_fixed_array_var {
 					// TODO Instead of the translated check, check if it's a pointer already
@@ -445,6 +447,7 @@ fn (mut g Gen) gen_assign_stmt(node_ ast.AssignStmt) {
 					g.expr(val)
 					g.write(', sizeof($typ_str))')
 				} else if is_decl {
+					g.is_shared = var_type.has_flag(.shared_f)
 					if is_fixed_array_init && !has_val {
 						if val is ast.ArrayInit {
 							g.array_init(val, ident.name)
@@ -476,11 +479,11 @@ fn (mut g Gen) gen_assign_stmt(node_ ast.AssignStmt) {
 						if op_overloaded {
 							g.op_arg(val, op_expected_right, val_type)
 						} else {
-							exp_type := if left.is_auto_deref_var() {
+							exp_type := if left.is_auto_deref_var() || var_type.has_flag(.shared_f) {
 								var_type.deref()
 							} else {
 								var_type
-							}
+							}.clear_flag(.shared_f) // don't reset the mutex, just change the value
 							g.expr_with_cast(val, val_type, exp_type)
 						}
 					}

vlib/v/tests/assign_shared_test.v

@@ -0,0 +1,13 @@
+struct AA {
+	a shared []int
+}
+
+fn test_assign_shared() {
+	a := AA{[1]}
+	lock a.a {
+		a.a = []int{cap: 10}
+	}
+	lock a.a {
+		assert a.a == []
+	}
+}