checker/cgen: fix `v := rlock m { m[key] or { default_val } }` (#9666)

vlib/v/ast/ast.v

@@ -77,9 +77,9 @@ pub:
 	expr     Expr
 	pos      token.Position
 	comments []Comment
-	is_expr  bool
 pub mut:
-	typ Type
+	is_expr bool
+	typ     Type
 }
 
 pub struct IntegerLiteral {

vlib/v/checker/checker.v

@@ -3504,7 +3504,23 @@ fn (mut c Checker) stmt(node ast.Stmt) {
 		ast.ExprStmt {
 			node.typ = c.expr(node.expr)
 			c.expected_type = ast.void_type
-			c.check_expr_opt_call(node.expr, ast.void_type)
+			mut or_typ := ast.void_type
+			match node.expr {
+				ast.IndexExpr {
+					if node.expr.or_expr.kind != .absent {
+						node.is_expr = true
+						or_typ = node.typ
+					}
+				}
+				ast.PrefixExpr {
+					if node.expr.or_block.kind != .absent {
+						node.is_expr = true
+						or_typ = node.typ
+					}
+				}
+				else {}
+			}
+			c.check_expr_opt_call(node.expr, or_typ)
 			// TODO This should work, even if it's prolly useless .-.
 			// node.typ = c.check_expr_opt_call(node.expr, ast.void_type)
 		}

vlib/v/gen/c/cgen.v

@@ -3832,6 +3832,9 @@ fn (mut g Gen) lock_expr(node ast.LockExpr) {
 	}
 	g.writeln('/*lock*/ {')
 	g.stmts_with_tmp_var(node.stmts, tmp_result)
+	if node.is_expr {
+		g.writeln(';')
+	}
 	g.writeln('}')
 	if node.lockeds.len == 0 {
 		// this should not happen

vlib/v/tests/shared_lock_expr_test.v

@@ -65,3 +65,59 @@ fn test_mult_ret_method() {
 	assert b == 13.125
 	assert c == -7.5
 }
+
+fn test_shared_lock_map_index_expr() {
+	shared m := map{
+		'qwe': 'asd'
+	}
+	for key in ['fdf', 'qwe'] {
+		v := rlock m {
+			m[key] or { 'key not found' }
+		}
+		if key == 'qwe' {
+			assert v == 'asd'
+		} else {
+			assert v == 'key not found'
+		}
+	}
+}
+
+fn test_shared_lock_array_index_expr() {
+	shared a := [-12.5, 6.25]
+	for i in -2 .. 4 {
+		v := rlock a {
+			a[i] or { 23.75 }
+		}
+		if i == 0 {
+			assert v == -12.5
+		} else if i == 1 {
+			assert v == 6.25
+		} else {
+			assert v == 23.75
+		}
+	}
+}
+
+struct DummySt {
+	a int
+}
+
+fn test_shared_lock_chan_rec_expr() {
+	ch := chan int{cap: 10}
+	shared st := DummySt{}
+	ch <- 7
+	ch <- -13
+	ch.close()
+	for i in 0 .. 3 {
+		v := rlock st {
+			<-ch or { -17 }
+		}
+		if i == 0 {
+			assert v == 7
+		} else if i == 1 {
+			assert v == -13
+		} else {
+			assert v == -17
+		}
+	}
+}