From 14d378c33043f51c371a4f154249d323b9bc5a3a Mon Sep 17 00:00:00 2001 From: yuyi Date: Mon, 8 Jul 2024 14:52:01 +0800 Subject: [PATCH] checker: check expr evaluated but not used (fix #21436) (#21816) --- vlib/v/checker/checker.v | 6 ++++++ vlib/v/checker/tests/expr_evaluated_but_not_used.out | 7 +++++++ vlib/v/checker/tests/expr_evaluated_but_not_used.vv | 10 ++++++++++ 3 files changed, 23 insertions(+) create mode 100644 vlib/v/checker/tests/expr_evaluated_but_not_used.out create mode 100644 vlib/v/checker/tests/expr_evaluated_but_not_used.vv diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v index 626e60ea1..4acbf3ea1 100644 --- a/vlib/v/checker/checker.v +++ b/vlib/v/checker/checker.v @@ -2219,6 +2219,12 @@ fn (mut c Checker) block(mut node ast.Block) { c.stmts(mut node.stmts) c.inside_unsafe = prev_unsafe } else { + if node.stmts.len > 0 && node.stmts.last() is ast.ExprStmt { + last_stmt := node.stmts.last() as ast.ExprStmt + if last_stmt.expr !in [ast.CallExpr, ast.IfExpr, ast.MatchExpr, ast.InfixExpr] { + c.warn('expression evaluated but not used', node.stmts.last().pos) + } + } c.stmts(mut node.stmts) } } diff --git a/vlib/v/checker/tests/expr_evaluated_but_not_used.out b/vlib/v/checker/tests/expr_evaluated_but_not_used.out new file mode 100644 index 000000000..97c40823d --- /dev/null +++ b/vlib/v/checker/tests/expr_evaluated_but_not_used.out @@ -0,0 +1,7 @@ +vlib/v/checker/tests/expr_evaluated_but_not_used.vv:7:3: warning: expression evaluated but not used + 5 | println(3) + 6 | println(4) + 7 | 5 + | ^ + 8 | } + 9 | println('works') diff --git a/vlib/v/checker/tests/expr_evaluated_but_not_used.vv b/vlib/v/checker/tests/expr_evaluated_but_not_used.vv new file mode 100644 index 000000000..40ddfe9fd --- /dev/null +++ b/vlib/v/checker/tests/expr_evaluated_but_not_used.vv @@ -0,0 +1,10 @@ +fn main() { + { + println(1) + println(2) + println(3) + println(4) + 5 + } + println('works') +} -- 2.39.5