cgen: automatic dereference and match fix

vlib/v/ast/ast.v

@@ -355,7 +355,7 @@ mut:
 	is_expr       bool // returns a value
 	return_type   table.Type
 	cond_type     table.Type // type of `x` in `match x {`
-	// expected_type table.Type // for debugging only
+	expected_type table.Type // for debugging only
 	is_sum_type   bool
 }
 

vlib/v/checker/checker.v

@@ -456,6 +456,7 @@ pub fn (c mut Checker) assign_stmt(assign_stmt mut ast.AssignStmt) {
 			})
 		}
 	}
+	c.expected_type = table.void_type
 }
 
 pub fn (c mut Checker) array_init(array_init mut ast.ArrayInit) table.Type {
@@ -839,7 +840,7 @@ pub fn (c mut Checker) ident(ident mut ast.Ident) table.Type {
 
 pub fn (c mut Checker) match_expr(node mut ast.MatchExpr) table.Type {
 	node.is_expr = c.expected_type != table.void_type
-	// node.expected_type = c.expected_type
+	node.expected_type = c.expected_type
 	cond_type := c.expr(node.cond)
 	if cond_type == 0 {
 		c.error('match 0 cond type', node.pos)

vlib/v/gen/cgen.v

@@ -1054,11 +1054,12 @@ fn (g mut Gen) match_expr(node ast.MatchExpr) {
 				g.writeln(') {')
 			}
 		}
-		if node.is_sum_type && branch.exprs.len > 0 {
+		// g.writeln('/* M sum_type=$node.is_sum_type is_expr=$node.is_expr exp_type=${g.typ(node.expected_type)}*/')
+		if node.is_sum_type && branch.exprs.len > 0 && !node.is_expr {
 			// The first node in expr is an ast.Type
 			// Use it to generate `it` variable.
-			fe := branch.exprs[0]
-			match fe {
+			first_expr := branch.exprs[0]
+			match first_expr {
 				ast.Type {
 					it_type := g.typ(it.typ)
 					// g.writeln('$it_type* it = ($it_type*)${tmp}.obj; // ST it')
@@ -1302,6 +1303,10 @@ fn (g mut Gen) return_statement(it ast.Return) {
 			}
 			// g.write('/*OPTIONAL*/')
 		}
+		if !table.type_is_ptr(g.fn_decl.return_type) && table.type_is_ptr(it.types[0]) {
+			// Automatic Dereference
+			g.write('*')
+		}
 		g.expr_with_cast(it.types[0], g.fn_decl.return_type, it.exprs[0])
 	}
 	g.writeln(';')