+// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
use crate::rustc::hir;
use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use if_chain::if_chain;
use crate::rustc::ty;
+use crate::rustc::{declare_tool_lint, lint_array};
use crate::rustc_errors::Applicability;
use crate::syntax::source_map::Span;
-use crate::utils::{in_macro, iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then};
use crate::utils::paths;
+use crate::utils::{in_macro, iter_input_pats, match_type, method_chain_args, snippet, span_lint_and_then};
+use if_chain::if_chain;
#[derive(Clone)]
pub struct Pass;
"using `result.map(f)`, where f is a function or closure that returns ()"
}
-
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(OPTION_MAP_UNIT_FN, RESULT_MAP_UNIT_FN)
let ty = cx.tables.expr_ty(expr);
if let ty::FnDef(id, _) = ty.sty {
- if let Some(fn_type) = cx.tcx.fn_sig(id).no_late_bound_regions() {
+ if let Some(fn_type) = cx.tcx.fn_sig(id).no_bound_vars() {
return is_unit_type(fn_type.output());
}
}
}
match expr.node {
- hir::ExprKind::Call(_, _) |
- hir::ExprKind::MethodCall(_, _, _) => {
+ hir::ExprKind::Call(_, _) | hir::ExprKind::MethodCall(_, _, _) => {
// Calls can't be reduced any more
Some(expr.span)
},
//
// We do not attempt to build a suggestion for those right now.
None
- }
+ },
}
},
_ => None,
None
}
-/// Builds a name for the let binding variable (var_arg)
+/// Builds a name for the let binding variable (`var_arg`)
///
/// `x.field` => `x_field`
/// `y` => `_y`
match &var_arg.node {
hir::ExprKind::Field(_, _) => snippet(cx, var_arg.span, "_").replace(".", "_"),
hir::ExprKind::Path(_) => format!("_{}", snippet(cx, var_arg.span, "")),
- _ => "_".to_string()
+ _ => "_".to_string(),
}
}
fn suggestion_msg(function_type: &str, map_type: &str) -> String {
format!(
"called `map(f)` on an {0} value where `f` is a unit {1}",
- map_type,
- function_type
+ map_type, function_type
)
}
let var_arg = &map_args[0];
let fn_arg = &map_args[1];
- let (map_type, variant, lint) =
- if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) {
- ("Option", "Some", OPTION_MAP_UNIT_FN)
- } else if match_type(cx, cx.tables.expr_ty(var_arg), &paths::RESULT) {
- ("Result", "Ok", RESULT_MAP_UNIT_FN)
- } else {
- return
- };
+ let (map_type, variant, lint) = if match_type(cx, cx.tables.expr_ty(var_arg), &paths::OPTION) {
+ ("Option", "Some", OPTION_MAP_UNIT_FN)
+ } else if match_type(cx, cx.tables.expr_ty(var_arg), &paths::RESULT) {
+ ("Result", "Ok", RESULT_MAP_UNIT_FN)
+ } else {
+ return;
+ };
if is_unit_function(cx, fn_arg) {
let msg = suggestion_msg("function", map_type);
- let suggestion = format!("if let {0}({1}) = {2} {{ {3}(...) }}",
- variant,
- let_binding_name(cx, var_arg),
- snippet(cx, var_arg.span, "_"),
- snippet(cx, fn_arg.span, "_"));
+ let suggestion = format!(
+ "if let {0}({1}) = {2} {{ {3}(...) }}",
+ variant,
+ let_binding_name(cx, var_arg),
+ snippet(cx, var_arg.span, "_"),
+ snippet(cx, fn_arg.span, "_")
+ );
span_lint_and_then(cx, lint, expr.span, &msg, |db| {
- db.span_suggestion_with_applicability(stmt.span,
- "try this",
- suggestion,
- Applicability::Unspecified);
+ db.span_suggestion_with_applicability(stmt.span, "try this", suggestion, Applicability::Unspecified);
});
} else if let Some((binding, closure_expr)) = unit_closure(cx, fn_arg) {
let msg = suggestion_msg("closure", map_type);
span_lint_and_then(cx, lint, expr.span, &msg, |db| {
if let Some(reduced_expr_span) = reduce_unit_expression(cx, closure_expr) {
- let suggestion = format!("if let {0}({1}) = {2} {{ {3} }}",
- variant,
- snippet(cx, binding.pat.span, "_"),
- snippet(cx, var_arg.span, "_"),
- snippet(cx, reduced_expr_span, "_"));
- db.span_suggestion(stmt.span, "try this", suggestion);
+ let suggestion = format!(
+ "if let {0}({1}) = {2} {{ {3} }}",
+ variant,
+ snippet(cx, binding.pat.span, "_"),
+ snippet(cx, var_arg.span, "_"),
+ snippet(cx, reduced_expr_span, "_")
+ );
+ db.span_suggestion_with_applicability(
+ stmt.span,
+ "try this",
+ suggestion,
+ Applicability::MachineApplicable, // snippet
+ );
} else {
- let suggestion = format!("if let {0}({1}) = {2} {{ ... }}",
- variant,
- snippet(cx, binding.pat.span, "_"),
- snippet(cx, var_arg.span, "_"));
- db.span_suggestion_with_applicability(stmt.span,
- "try this",
- suggestion,
- Applicability::Unspecified);
+ let suggestion = format!(
+ "if let {0}({1}) = {2} {{ ... }}",
+ variant,
+ snippet(cx, binding.pat.span, "_"),
+ snippet(cx, var_arg.span, "_")
+ );
+ db.span_suggestion_with_applicability(stmt.span, "try this", suggestion, Applicability::Unspecified);
}
});
}
projects / rust.git / blobdiff