fix a bug that caused internal test fail

Author: J-ZhengLi

clippy_lints/src/matches/nop_match.rs

@@ -80,26 +80,29 @@ pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>) {
 }
 
 fn check_if_let(cx: &LateContext<'_>, if_let: &higher::IfLet<'_>) -> bool {
-    if let Some(else_block) = if_let.if_else {
+    if let Some(if_else) = if_let.if_else {
         if !pat_same_as_expr(if_let.let_pat, peel_blocks_with_stmt(if_let.if_then)) {
             return false;
         }
 
-        let else_expr = peel_blocks_with_stmt(else_block);
         // Recurrsively check for each `else if let` phrase,
-        if let Some(ref nested_if_let) = higher::IfLet::hir(cx, else_expr) {
+        if let Some(ref nested_if_let) = higher::IfLet::hir(cx, if_else) {
             return check_if_let(cx, nested_if_let);
         }
-        let ret = strip_return(else_expr);
-        let let_expr_ty = cx.typeck_results().expr_ty(if_let.let_expr);
-        if is_type_diagnostic_item(cx, let_expr_ty, sym::Option) {
-            if let ExprKind::Path(ref qpath) = ret.kind {
-                return is_lang_ctor(cx, qpath, OptionNone) || eq_expr_value(cx, if_let.let_expr, ret);
+
+        if matches!(if_else.kind, ExprKind::Block(..)) {
+            let else_expr = peel_blocks_with_stmt(if_else);
+            let ret = strip_return(else_expr);
+            let let_expr_ty = cx.typeck_results().expr_ty(if_let.let_expr);
+            if is_type_diagnostic_item(cx, let_expr_ty, sym::Option) {
+                if let ExprKind::Path(ref qpath) = ret.kind {
+                    return is_lang_ctor(cx, qpath, OptionNone) || eq_expr_value(cx, if_let.let_expr, ret);
+                }
+            } else {
+                return eq_expr_value(cx, if_let.let_expr, ret);
             }
-        } else {
-            return eq_expr_value(cx, if_let.let_expr, ret);
+            return true;
         }
-        return true;
     }
     false
 }

tests/ui/nop_match.fixed

@@ -3,6 +3,7 @@
 #![allow(clippy::manual_map)]
 #![allow(dead_code)]
 
+#[derive(Clone, Copy)]
 enum Choice {
     A,
     B,
@@ -60,8 +61,16 @@ fn if_let_result(x: Result<(), i32>) {
     let _: Result<(), i32> = if let Err(e) = Ok(1) { Err(e) } else { x };
 }
 
-fn custom_enum_a(x: Choice) -> Choice {
-    x
+fn if_let_custom_enum(x: Choice) {
+    let _: Choice = x;
+    // Don't trigger
+    let _: Choice = if let Choice::A = x {
+        Choice::A
+    } else if true {
+        Choice::B
+    } else {
+        x
+    };
 }
 
 fn main() {}

tests/ui/nop_match.rs

@@ -3,6 +3,7 @@
 #![allow(clippy::manual_map)]
 #![allow(dead_code)]
 
+#[derive(Clone, Copy)]
 enum Choice {
     A,
     B,
@@ -79,16 +80,24 @@ fn if_let_result(x: Result<(), i32>) {
     let _: Result<(), i32> = if let Err(e) = Ok(1) { Err(e) } else { x };
 }
 
-fn custom_enum_a(x: Choice) -> Choice {
-    if let Choice::A = x {
+fn if_let_custom_enum(x: Choice) {
+    let _: Choice = if let Choice::A = x {
         Choice::A
     } else if let Choice::B = x {
         Choice::B
     } else if let Choice::C = x {
         Choice::C
     } else {
         x
-    }
+    };
+    // Don't trigger
+    let _: Choice = if let Choice::A = x {
+        Choice::A
+    } else if true {
+        Choice::B
+    } else {
+        x
+    };
 }
 
 fn main() {}

tests/ui/nop_match.stderr

@@ -1,5 +1,5 @@
 error: this match expression is unnecessary
-  --> $DIR/nop_match.rs:14:18
+  --> $DIR/nop_match.rs:15:18
    |
 LL |       let _: i32 = match x {
    |  __________________^
@@ -13,7 +13,7 @@ LL | |     };
    = note: `-D clippy::nop-match` implied by `-D warnings`
 
 error: this match expression is unnecessary
-  --> $DIR/nop_match.rs:23:21
+  --> $DIR/nop_match.rs:24:21
    |
 LL |       let _: Choice = match se {
    |  _____________________^
@@ -25,7 +25,7 @@ LL | |     };
    | |_____^ help: replace it with: `se`
 
 error: this match expression is unnecessary
-  --> $DIR/nop_match.rs:45:26
+  --> $DIR/nop_match.rs:46:26
    |
 LL |       let _: Option<i32> = match x {
    |  __________________________^
@@ -35,7 +35,7 @@ LL | |     };
    | |_____^ help: replace it with: `x`
 
 error: this match expression is unnecessary
-  --> $DIR/nop_match.rs:61:31
+  --> $DIR/nop_match.rs:62:31
    |
 LL |       let _: Result<i32, i32> = match Ok(1) {
    |  _______________________________^
@@ -45,7 +45,7 @@ LL | |     };
    | |_____^ help: replace it with: `Ok(1)`
 
 error: this match expression is unnecessary
-  --> $DIR/nop_match.rs:65:31
+  --> $DIR/nop_match.rs:66:31
    |
 LL |       let _: Result<i32, i32> = match func_ret_err(0_i32) {
    |  _______________________________^
@@ -55,33 +55,34 @@ LL | |     };
    | |_____^ help: replace it with: `func_ret_err(0_i32)`
 
 error: this if-let expression is unnecessary
-  --> $DIR/nop_match.rs:72:5
+  --> $DIR/nop_match.rs:73:5
    |
 LL |     if let Some(a) = Some(1) { Some(a) } else { None }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `Some(1)`
 
 error: this if-let expression is unnecessary
-  --> $DIR/nop_match.rs:76:30
+  --> $DIR/nop_match.rs:77:30
    |
 LL |     let _: Result<(), i32> = if let Err(e) = x { Err(e) } else { x };
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `x`
 
 error: this if-let expression is unnecessary
-  --> $DIR/nop_match.rs:77:30
+  --> $DIR/nop_match.rs:78:30
    |
 LL |     let _: Result<(), i32> = if let Ok(val) = x { Ok(val) } else { x };
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `x`
 
 error: this if-let expression is unnecessary
-  --> $DIR/nop_match.rs:83:5
+  --> $DIR/nop_match.rs:84:21
    |
-LL | /     if let Choice::A = x {
+LL |       let _: Choice = if let Choice::A = x {
+   |  _____________________^
 LL | |         Choice::A
 LL | |     } else if let Choice::B = x {
 LL | |         Choice::B
 ...  |
 LL | |         x
-LL | |     }
+LL | |     };
    | |_____^ help: replace it with: `x`
 
 error: aborting due to 9 previous errors