checker: fix unresolved variables error on assignments

vlib/v/checker/checker.v

@@ -31,7 +31,6 @@ pub mut:
 	pref             &pref.Preferences // Preferences shared from V struct
 	in_for_count     int // if checker is currently in an for loop
 	// checked_ident  string // to avoid infinit checker loops
-	var_decl_name    string
 	returns          bool
 	scope_returns    bool
 	mod              string // current module name
@@ -1258,9 +1257,6 @@ pub fn (mut c Checker) assign_stmt(mut assign_stmt ast.AssignStmt) {
 		if is_decl && ident.name != '_' {
 			c.check_valid_snake_case(ident.name, 'variable name', ident.pos)
 		}
-		if assign_stmt.op == .decl_assign {
-			c.var_decl_name = ident.name
-		}
 		mut ident_var_info := ident.var_info()
 		// c.assigned_var_name = ident.name
 		if assign_stmt.op == .assign {
@@ -1282,7 +1278,6 @@ pub fn (mut c Checker) assign_stmt(mut assign_stmt ast.AssignStmt) {
 			c.check_expr_opt_call(assign_stmt.right[i], assign_stmt.right_types[i], true)
 		}
 	}
-	c.var_decl_name = ''
 	c.expected_type = table.void_type
 	// c.assigned_var_name = ''
 }
@@ -1823,11 +1818,6 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
 }
 
 pub fn (mut c Checker) ident(mut ident ast.Ident) table.Type {
-	if ident.name == c.var_decl_name { // c.checked_ident {
-		// Do not allow `x := x`
-		c.error('unresolved: `$ident.name`', ident.pos)
-		return table.void_type
-	}
 	// TODO: move this
 	if c.const_deps.len > 0 {
 		mut name := ident.name

vlib/v/checker/tests/assign_expr_unresolved_variables_err_a.out

@@ -0,0 +1,6 @@
+vlib/v/checker/tests/assign_expr_unresolved_variables_err_a.v:2:7: error: unresolved variables `a`
+    1 | fn main() {
+    2 |     a := a
+      |          ^
+    3 |     println(a)
+    4 | }

vlib/v/checker/tests/assign_expr_unresolved_variables_err_a.vv

@@ -0,0 +1,4 @@
+fn main() {
+	a := a
+	println(a)
+}

vlib/v/checker/tests/assign_expr_unresolved_variables_err_b.out

@@ -0,0 +1,6 @@
+vlib/v/checker/tests/assign_expr_unresolved_variables_err_b.v:2:10: error: unresolved variables `a`
+    1 | fn main() {
+    2 |     a, b := a, b
+      |             ^
+    3 |     println('$a, $b')
+    4 | }

vlib/v/checker/tests/assign_expr_unresolved_variables_err_b.vv

@@ -0,0 +1,4 @@
+fn main() {
+	a, b := a, b
+	println('$a, $b')
+}

vlib/v/checker/tests/assign_expr_unresolved_variables_err_c.out

@@ -0,0 +1,6 @@
+vlib/v/checker/tests/assign_expr_unresolved_variables_err_c.v:2:10: error: unresolved variables `a`
+    1 | fn main() {
+    2 |     a, b := a + 1, b * 3
+      |             ^
+    3 |     println('$a, $b')
+    4 | }

vlib/v/checker/tests/assign_expr_unresolved_variables_err_c.vv

@@ -0,0 +1,4 @@
+fn main() {
+	a, b := a + 1, b * 3
+	println('$a, $b')
+}

vlib/v/parser/assign.v

@@ -9,6 +9,23 @@ fn (mut p Parser) assign_stmt() ast.Stmt {
 	return p.partial_assign_stmt([])
 }
 
+fn (mut p Parser) check_unresolved_variables(idents []ast.Ident, expr ast.Expr) {
+	match expr {
+		ast.Ident {
+			for ident in idents {
+				if ident.name == it.name {
+					p.error_with_pos('unresolved variables `$it.name`', it.pos)
+				}
+			}
+		}
+		ast.InfixExpr {
+			p.check_unresolved_variables(idents, it.left)
+			p.check_unresolved_variables(idents, it.right)
+		}
+		else {}
+	}
+}
+
 fn (mut p Parser) partial_assign_stmt(known_lhs []ast.Ident) ast.Stmt {
 	mut idents := known_lhs
 	mut op := p.tok.kind
@@ -24,6 +41,12 @@ fn (mut p Parser) partial_assign_stmt(known_lhs []ast.Ident) ast.Stmt {
 	pos := p.tok.position()
 	exprs := p.parse_assign_rhs()
 	is_decl := op == .decl_assign
+	if is_decl {
+		// a, b := a + 1, b
+		for expr in exprs {
+			p.check_unresolved_variables(idents, expr)
+		}
+	}
 	for i, ident in idents {
 		known_var := p.scope.known_var(ident.name)
 		if !is_decl && !known_var {