From ede977cf3131caeaac71e36c32390ca3c5b4deda Mon Sep 17 00:00:00 2001
From: F3real <stefan92ff@yandex.com>
Date: Mon, 9 Aug 2021 09:49:55 +0200
Subject: [PATCH] Update suggestion in case of index for unnecessary_operation
lint
---
clippy_lints/src/no_effect.rs | 71 ++++++++++++++++++------
tests/ui/unnecessary_operation.fixed | 4 +-
tests/ui/unnecessary_operation.stderr | 80 +++++++++++++--------------
3 files changed, 95 insertions(+), 60 deletions(-)
diff --git a/clippy_lints/src/no_effect.rs b/clippy_lints/src/no_effect.rs
index e07518b2586..c50980e1cf6 100644
--- a/clippy_lints/src/no_effect.rs
+++ b/clippy_lints/src/no_effect.rs
@@ -94,28 +94,63 @@ impl<'tcx> LateLintPass<'tcx> for NoEffect {
if has_no_effect(cx, expr) {
span_lint_hir(cx, NO_EFFECT, expr.hir_id, stmt.span, "statement with no effect");
} else if let Some(reduced) = reduce_expression(cx, expr) {
- let mut snippet = String::new();
- for e in reduced {
+ for e in &reduced {
if e.span.from_expansion() {
return;
}
- if let Some(snip) = snippet_opt(cx, e.span) {
- snippet.push_str(&snip);
- snippet.push(';');
- } else {
- return;
- }
}
- span_lint_hir_and_then(
- cx,
- UNNECESSARY_OPERATION,
- expr.hir_id,
- stmt.span,
- "statement can be reduced",
- |diag| {
- diag.span_suggestion(stmt.span, "replace it with", snippet, Applicability::MachineApplicable);
- },
- );
+ if let ExprKind::Index(..) = &expr.kind {
+ let snippet;
+ if_chain! {
+ if let Some(arr) = snippet_opt(cx, reduced[0].span);
+ if let Some(func) = snippet_opt(cx, reduced[1].span);
+ then {
+ snippet = format!("assert!({}.len() > {});", &arr, &func);
+ } else {
+ return;
+ }
+ }
+ span_lint_hir_and_then(
+ cx,
+ UNNECESSARY_OPERATION,
+ expr.hir_id,
+ stmt.span,
+ "unnecessary operation",
+ |diag| {
+ diag.span_suggestion(
+ stmt.span,
+ "statement can be written as",
+ snippet,
+ Applicability::MaybeIncorrect,
+ );
+ },
+ );
+ } else {
+ let mut snippet = String::new();
+ for e in reduced {
+ if let Some(snip) = snippet_opt(cx, e.span) {
+ snippet.push_str(&snip);
+ snippet.push(';');
+ } else {
+ return;
+ }
+ }
+ span_lint_hir_and_then(
+ cx,
+ UNNECESSARY_OPERATION,
+ expr.hir_id,
+ stmt.span,
+ "unnecessary operation",
+ |diag| {
+ diag.span_suggestion(
+ stmt.span,
+ "statement can be reduced to",
+ snippet,
+ Applicability::MachineApplicable,
+ );
+ },
+ );
+ }
}
}
}
diff --git a/tests/ui/unnecessary_operation.fixed b/tests/ui/unnecessary_operation.fixed
index 2fca96c4cd5..bf0ec8deb34 100644
--- a/tests/ui/unnecessary_operation.fixed
+++ b/tests/ui/unnecessary_operation.fixed
@@ -62,10 +62,10 @@ fn main() {
get_number();
5;get_number();
42;get_number();
- [42, 55];get_usize();
+ assert!([42, 55].len() > get_usize());
42;get_number();
get_number();
- [42; 55];get_usize();
+ assert!([42; 55].len() > get_usize());
get_number();
String::from("blah");
diff --git a/tests/ui/unnecessary_operation.stderr b/tests/ui/unnecessary_operation.stderr
index f88c9f9908b..f66d08ecb82 100644
--- a/tests/ui/unnecessary_operation.stderr
+++ b/tests/ui/unnecessary_operation.stderr
@@ -1,128 +1,128 @@
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:51:5
|
LL | Tuple(get_number());
- | ^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
|
= note: `-D clippy::unnecessary-operation` implied by `-D warnings`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:52:5
|
LL | Struct { field: get_number() };
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:53:5
|
LL | Struct { ..get_struct() };
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_struct();`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_struct();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:54:5
|
LL | Enum::Tuple(get_number());
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:55:5
|
LL | Enum::Struct { field: get_number() };
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:56:5
|
LL | 5 + get_number();
- | ^^^^^^^^^^^^^^^^^ help: replace it with: `5;get_number();`
+ | ^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `5;get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:57:5
|
LL | *&get_number();
- | ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:58:5
|
LL | &get_number();
- | ^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:59:5
|
LL | (5, 6, get_number());
- | ^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `5;6;get_number();`
+ | ^^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `5;6;get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:60:5
|
LL | box get_number();
- | ^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:61:5
|
LL | get_number()..;
- | ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:62:5
|
LL | ..get_number();
- | ^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:63:5
|
LL | 5..get_number();
- | ^^^^^^^^^^^^^^^^ help: replace it with: `5;get_number();`
+ | ^^^^^^^^^^^^^^^^ help: statement can be reduced to: `5;get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:64:5
|
LL | [42, get_number()];
- | ^^^^^^^^^^^^^^^^^^^ help: replace it with: `42;get_number();`
+ | ^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `42;get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:65:5
|
LL | [42, 55][get_usize()];
- | ^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `[42, 55];get_usize();`
+ | ^^^^^^^^^^^^^^^^^^^^^^ help: statement can be written as: `assert!([42, 55].len() > get_usize());`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:66:5
|
LL | (42, get_number()).1;
- | ^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `42;get_number();`
+ | ^^^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `42;get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:67:5
|
LL | [get_number(); 55];
- | ^^^^^^^^^^^^^^^^^^^ help: replace it with: `get_number();`
+ | ^^^^^^^^^^^^^^^^^^^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:68:5
|
LL | [42; 55][get_usize()];
- | ^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `[42; 55];get_usize();`
+ | ^^^^^^^^^^^^^^^^^^^^^^ help: statement can be written as: `assert!([42; 55].len() > get_usize());`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:69:5
|
LL | / {
LL | | get_number()
LL | | };
- | |______^ help: replace it with: `get_number();`
+ | |______^ help: statement can be reduced to: `get_number();`
-error: statement can be reduced
+error: unnecessary operation
--> $DIR/unnecessary_operation.rs:72:5
|
LL | / FooString {
LL | | s: String::from("blah"),
LL | | };
- | |______^ help: replace it with: `String::from("blah");`
+ | |______^ help: statement can be reduced to: `String::from("blah");`
error: aborting due to 20 previous errors