Auto merge of rust-lang#10013 - Jarcho:issue_9886, r=Manishearth

Don't lint `manual_assert` in `else if`

fixes rust-lang#9886
changelog: `manual_assert`: Don't lint in `else if`

clippy_lints/src/manual_assert.rs

@@ -2,7 +2,7 @@ use crate::rustc_lint::LintContext;
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::macros::{root_macro_call, FormatArgsExpn};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{peel_blocks_with_stmt, span_extract_comment, sugg};
+use clippy_utils::{is_else_clause, peel_blocks_with_stmt, span_extract_comment, sugg};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
@@ -47,6 +47,10 @@ impl<'tcx> LateLintPass<'tcx> for ManualAssert {
             if cx.tcx.item_name(macro_call.def_id) == sym::panic;
             if !cx.tcx.sess.source_map().is_multiline(cond.span);
             if let Some(format_args) = FormatArgsExpn::find_nested(cx, then, macro_call.expn);
+            // Don't change `else if foo { panic!(..) }` to `else { assert!(foo, ..) }` as it just
+            // shuffles the condition around.
+            // Should this have a config value?
+            if !is_else_clause(cx.tcx, expr);
             then {
                 let mut applicability = Applicability::MachineApplicable;
                 let format_args_snip = snippet_with_applicability(cx, format_args.inputs_span(), "..", &mut applicability);

tests/ui/manual_assert.edition2018.fixed

@@ -62,6 +62,11 @@ fn main() {
         panic!("panic5");
     }
     assert!(!a.is_empty(), "with expansion {}", one!());
+    if a.is_empty() {
+        let _ = 0;
+    } else if a.len() == 1 {
+        panic!("panic6");
+    }
 }
 
 fn issue7730(a: u8) {

tests/ui/manual_assert.edition2021.fixed

@@ -50,6 +50,11 @@ fn main() {
     assert!(!(b.is_empty() || a.is_empty()), "panic4");
     assert!(!(a.is_empty() || !b.is_empty()), "panic5");
     assert!(!a.is_empty(), "with expansion {}", one!());
+    if a.is_empty() {
+        let _ = 0;
+    } else if a.len() == 1 {
+        panic!("panic6");
+    }
 }
 
 fn issue7730(a: u8) {

tests/ui/manual_assert.edition2021.stderr

@@ -65,7 +65,7 @@ LL | |     }
    | |_____^ help: try instead: `assert!(!a.is_empty(), "with expansion {}", one!());`
 
 error: only a `panic!` in `if`-then statement
-  --> $DIR/manual_assert.rs:73:5
+  --> $DIR/manual_assert.rs:78:5
    |
 LL | /     if a > 2 {
 LL | |         // comment

tests/ui/manual_assert.rs

@@ -66,6 +66,11 @@ fn main() {
     if a.is_empty() {
         panic!("with expansion {}", one!())
     }
+    if a.is_empty() {
+        let _ = 0;
+    } else if a.len() == 1 {
+        panic!("panic6");
+    }
 }
 
 fn issue7730(a: u8) {