40 lines
1.6 KiB
Rust
40 lines
1.6 KiB
Rust
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use syntax::ast::*;
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use rustc::lint::{Context, LintPass, LintArray};
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use rustc::middle::ty;
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use utils::{span_lint, match_def_path, walk_ptrs_ty};
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#[derive(Copy,Clone)]
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pub struct MethodsPass;
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declare_lint!(pub OPTION_UNWRAP_USED, Warn,
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"Warn on using unwrap() on an Option value");
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declare_lint!(pub RESULT_UNWRAP_USED, Allow,
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"Warn on using unwrap() on a Result value");
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impl LintPass for MethodsPass {
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fn get_lints(&self) -> LintArray {
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lint_array!(OPTION_UNWRAP_USED, RESULT_UNWRAP_USED)
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}
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fn check_expr(&mut self, cx: &Context, expr: &Expr) {
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if let ExprMethodCall(ref ident, _, ref args) = expr.node {
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if ident.node.name == "unwrap" {
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if let ty::TyEnum(did, _) = walk_ptrs_ty(cx.tcx.expr_ty(&*args[0])).sty {
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if match_def_path(cx, did.did, &["core", "option", "Option"]) {
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span_lint(cx, OPTION_UNWRAP_USED, expr.span,
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"used unwrap() on an Option value. If you don't want \
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to handle the None case gracefully, consider using
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expect() to provide a better panic message.");
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}
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else if match_def_path(cx, did.did, &["core", "result", "Result"]) {
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span_lint(cx, RESULT_UNWRAP_USED, expr.span,
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"used unwrap() on a Result value. Graceful handling \
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of Err values is preferred.");
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}
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}
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}
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}
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}
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}
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