From 9306e9a4df2e6f8ed577fff3c82006c532ca51d2 Mon Sep 17 00:00:00 2001
From: Dany Marcoux <dmarcoux@posteo.de>
Date: Wed, 18 May 2022 20:28:11 +0200
Subject: [PATCH 01/10] Ignore bodies containing `todo!()` in
 `clippy::if_same_then_else`

---
 clippy_lints/src/copies.rs    | 18 +++++++++++++++++-
 tests/ui/if_same_then_else.rs |  3 +++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 1deff9684a1..6f92caf7391 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -12,7 +12,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::walk_chain;
 use rustc_span::source_map::SourceMap;
-use rustc_span::{BytePos, Span, Symbol};
+use rustc_span::{sym, BytePos, Span, Symbol};
 use std::borrow::Cow;
 
 declare_clippy_lint! {
@@ -365,6 +365,21 @@ fn eq_stmts(
         .all(|b| get_stmt(b).map_or(false, |s| eq.eq_stmt(s, stmt)))
 }
 
+fn block_contains_todo_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
+    dbg!(block);
+    if let Some(macro_def_id) = block.span.ctxt().outer_expn_data().macro_def_id {
+        dbg!(macro_def_id);
+        if let Some(diagnostic_name) = cx.tcx.get_diagnostic_name(macro_def_id) {
+            dbg!(diagnostic_name);
+            diagnostic_name == sym::todo_macro
+        } else {
+            false
+        }
+    } else {
+        false
+    }
+}
+
 fn scan_block_for_eq(cx: &LateContext<'_>, _conds: &[&Expr<'_>], block: &Block<'_>, blocks: &[&Block<'_>]) -> BlockEq {
     let mut eq = SpanlessEq::new(cx);
     let mut eq = eq.inter_expr();
@@ -398,6 +413,7 @@ fn scan_block_for_eq(cx: &LateContext<'_>, _conds: &[&Expr<'_>], block: &Block<'
             moved_locals,
         };
     }
+
     let end_search_start = block.stmts[start_end_eq..]
         .iter()
         .rev()
diff --git a/tests/ui/if_same_then_else.rs b/tests/ui/if_same_then_else.rs
index ef956745500..767185c207b 100644
--- a/tests/ui/if_same_then_else.rs
+++ b/tests/ui/if_same_then_else.rs
@@ -126,6 +126,9 @@ fn if_same_then_else() {
             _ => 4,
         };
     }
+
+    // Issue #8836
+    if true { todo!() } else { todo!() }
 }
 
 // Issue #2423. This was causing an ICE.

From 7cb4cef123a53534aaaa3956d4edf079d8482c6b Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Thu, 16 Jun 2022 21:29:43 +0900
Subject: [PATCH 02/10] feat(fix): ignore todo! and unimplemented! in
 if_same_then_else

---
 clippy_lints/src/copies.rs        | 51 ++++++++++++++++--------
 tests/ui/if_same_then_else.rs     | 64 +++++++++++++++++++++++++++++--
 tests/ui/if_same_then_else.stderr | 20 +++++-----
 3 files changed, 106 insertions(+), 29 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 6f92caf7391..a771656c20f 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::{span_lint_and_note, span_lint_and_then};
+use clippy_utils::macros::macro_backtrace;
 use clippy_utils::source::{first_line_of_span, indent_of, reindent_multiline, snippet, snippet_opt};
 use clippy_utils::{
     eq_expr_value, get_enclosing_block, hash_expr, hash_stmt, if_sequence, is_else_clause, is_lint_allowed,
@@ -7,14 +8,16 @@ use clippy_utils::{
 use core::iter;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit;
-use rustc_hir::{BinOpKind, Block, Expr, ExprKind, HirId, Stmt, StmtKind};
+use rustc_hir::{BinOpKind, Block, Expr, ExprKind, HirId, QPath, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::walk_chain;
 use rustc_span::source_map::SourceMap;
-use rustc_span::{sym, BytePos, Span, Symbol};
+use rustc_span::{BytePos, Span, Symbol};
 use std::borrow::Cow;
 
+const ACCEPTABLE_MACRO: [&str; 2] = ["todo", "unimplemented"];
+
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for consecutive `if`s with the same condition.
@@ -195,7 +198,12 @@ fn lint_if_same_then_else(cx: &LateContext<'_>, conds: &[&Expr<'_>], blocks: &[&
         .array_windows::<2>()
         .enumerate()
         .fold(true, |all_eq, (i, &[lhs, rhs])| {
-            if eq.eq_block(lhs, rhs) && !contains_let(conds[i]) && conds.get(i + 1).map_or(true, |e| !contains_let(e)) {
+            if eq.eq_block(lhs, rhs)
+                && !contains_acceptable_macro(cx, lhs)
+                && !contains_acceptable_macro(cx, rhs)
+                && !contains_let(conds[i])
+                && conds.get(i + 1).map_or(true, |e| !contains_let(e))
+            {
                 span_lint_and_note(
                     cx,
                     IF_SAME_THEN_ELSE,
@@ -365,19 +373,33 @@ fn eq_stmts(
         .all(|b| get_stmt(b).map_or(false, |s| eq.eq_stmt(s, stmt)))
 }
 
-fn block_contains_todo_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
-    dbg!(block);
-    if let Some(macro_def_id) = block.span.ctxt().outer_expn_data().macro_def_id {
-        dbg!(macro_def_id);
-        if let Some(diagnostic_name) = cx.tcx.get_diagnostic_name(macro_def_id) {
-            dbg!(diagnostic_name);
-            diagnostic_name == sym::todo_macro
-        } else {
-            false
+fn contains_acceptable_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
+    for stmt in block.stmts {
+        match stmt.kind {
+            StmtKind::Semi(semi_expr) if acceptable_macro(cx, semi_expr) => return true,
+            _ => {},
         }
-    } else {
-        false
     }
+
+    if let Some(block_expr) = block.expr
+        && acceptable_macro(cx, block_expr)
+    {
+        return true
+    }
+
+    false
+}
+
+fn acceptable_macro(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+    if let ExprKind::Call(call_expr, _)  = expr.kind
+        && let ExprKind::Path(QPath::Resolved(None, path)) = call_expr.kind
+        && macro_backtrace(path.span).any(|macro_call| {
+            ACCEPTABLE_MACRO.contains(&cx.tcx.item_name(macro_call.def_id).as_str())
+    }) {
+        return true;
+    }
+
+    false
 }
 
 fn scan_block_for_eq(cx: &LateContext<'_>, _conds: &[&Expr<'_>], block: &Block<'_>, blocks: &[&Block<'_>]) -> BlockEq {
@@ -413,7 +435,6 @@ fn scan_block_for_eq(cx: &LateContext<'_>, _conds: &[&Expr<'_>], block: &Block<'
             moved_locals,
         };
     }
-
     let end_search_start = block.stmts[start_end_eq..]
         .iter()
         .rev()
diff --git a/tests/ui/if_same_then_else.rs b/tests/ui/if_same_then_else.rs
index 767185c207b..2598c2ab426 100644
--- a/tests/ui/if_same_then_else.rs
+++ b/tests/ui/if_same_then_else.rs
@@ -6,7 +6,9 @@
     clippy::no_effect,
     clippy::unused_unit,
     clippy::zero_divided_by_zero,
-    clippy::branches_sharing_code
+    clippy::branches_sharing_code,
+    dead_code,
+    unreachable_code
 )]
 
 struct Foo {
@@ -126,9 +128,6 @@ fn if_same_then_else() {
             _ => 4,
         };
     }
-
-    // Issue #8836
-    if true { todo!() } else { todo!() }
 }
 
 // Issue #2423. This was causing an ICE.
@@ -158,4 +157,61 @@ mod issue_5698 {
     }
 }
 
+mod issue_8836 {
+    fn do_not_lint() {
+        if true {
+            todo!()
+        } else {
+            todo!()
+        }
+        if true {
+            todo!();
+        } else {
+            todo!();
+        }
+        if true {
+            unimplemented!()
+        } else {
+            unimplemented!()
+        }
+        if true {
+            unimplemented!();
+        } else {
+            unimplemented!();
+        }
+
+        if true {
+            println!("FOO");
+            todo!();
+        } else {
+            println!("FOO");
+            todo!();
+        }
+
+        if true {
+            println!("FOO");
+            unimplemented!();
+        } else {
+            println!("FOO");
+            unimplemented!();
+        }
+
+        if true {
+            println!("FOO");
+            todo!()
+        } else {
+            println!("FOO");
+            todo!()
+        }
+
+        if true {
+            println!("FOO");
+            unimplemented!()
+        } else {
+            println!("FOO");
+            unimplemented!()
+        }
+    }
+}
+
 fn main() {}
diff --git a/tests/ui/if_same_then_else.stderr b/tests/ui/if_same_then_else.stderr
index 2f38052fc20..2cdf442486a 100644
--- a/tests/ui/if_same_then_else.stderr
+++ b/tests/ui/if_same_then_else.stderr
@@ -1,5 +1,5 @@
 error: this `if` has identical blocks
-  --> $DIR/if_same_then_else.rs:21:13
+  --> $DIR/if_same_then_else.rs:23:13
    |
 LL |       if true {
    |  _____________^
@@ -13,7 +13,7 @@ LL | |     } else {
    |
    = note: `-D clippy::if-same-then-else` implied by `-D warnings`
 note: same as this
-  --> $DIR/if_same_then_else.rs:29:12
+  --> $DIR/if_same_then_else.rs:31:12
    |
 LL |       } else {
    |  ____________^
@@ -26,7 +26,7 @@ LL | |     }
    | |_____^
 
 error: this `if` has identical blocks
-  --> $DIR/if_same_then_else.rs:65:21
+  --> $DIR/if_same_then_else.rs:67:21
    |
 LL |       let _ = if true {
    |  _____________________^
@@ -35,7 +35,7 @@ LL | |     } else {
    | |_____^
    |
 note: same as this
-  --> $DIR/if_same_then_else.rs:67:12
+  --> $DIR/if_same_then_else.rs:69:12
    |
 LL |       } else {
    |  ____________^
@@ -45,7 +45,7 @@ LL | |     };
    | |_____^
 
 error: this `if` has identical blocks
-  --> $DIR/if_same_then_else.rs:72:21
+  --> $DIR/if_same_then_else.rs:74:21
    |
 LL |       let _ = if true {
    |  _____________________^
@@ -54,7 +54,7 @@ LL | |     } else {
    | |_____^
    |
 note: same as this
-  --> $DIR/if_same_then_else.rs:74:12
+  --> $DIR/if_same_then_else.rs:76:12
    |
 LL |       } else {
    |  ____________^
@@ -64,7 +64,7 @@ LL | |     };
    | |_____^
 
 error: this `if` has identical blocks
-  --> $DIR/if_same_then_else.rs:88:21
+  --> $DIR/if_same_then_else.rs:90:21
    |
 LL |       let _ = if true {
    |  _____________________^
@@ -73,7 +73,7 @@ LL | |     } else {
    | |_____^
    |
 note: same as this
-  --> $DIR/if_same_then_else.rs:90:12
+  --> $DIR/if_same_then_else.rs:92:12
    |
 LL |       } else {
    |  ____________^
@@ -83,7 +83,7 @@ LL | |     };
    | |_____^
 
 error: this `if` has identical blocks
-  --> $DIR/if_same_then_else.rs:95:13
+  --> $DIR/if_same_then_else.rs:97:13
    |
 LL |       if true {
    |  _____________^
@@ -96,7 +96,7 @@ LL | |     } else {
    | |_____^
    |
 note: same as this
-  --> $DIR/if_same_then_else.rs:102:12
+  --> $DIR/if_same_then_else.rs:104:12
    |
 LL |       } else {
    |  ____________^

From a5b6d25ca4f1600a158ffb68301dd816c8eda3cf Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Fri, 17 Jun 2022 10:10:40 +0900
Subject: [PATCH 03/10] use get_diagnostic_name for checking macro_call

---
 clippy_lints/src/copies.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index a771656c20f..9d1ca3588b3 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -13,11 +13,9 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::walk_chain;
 use rustc_span::source_map::SourceMap;
-use rustc_span::{BytePos, Span, Symbol};
+use rustc_span::{sym, BytePos, Span, Symbol};
 use std::borrow::Cow;
 
-const ACCEPTABLE_MACRO: [&str; 2] = ["todo", "unimplemented"];
-
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for consecutive `if`s with the same condition.
@@ -394,7 +392,10 @@ fn acceptable_macro(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     if let ExprKind::Call(call_expr, _)  = expr.kind
         && let ExprKind::Path(QPath::Resolved(None, path)) = call_expr.kind
         && macro_backtrace(path.span).any(|macro_call| {
-            ACCEPTABLE_MACRO.contains(&cx.tcx.item_name(macro_call.def_id).as_str())
+            matches!(
+                &cx.tcx.get_diagnostic_name(macro_call.def_id),
+                Some(sym::todo_macro | sym::unimplemented_macro)
+            )
     }) {
         return true;
     }

From 697c75ef4b39f1560bf087841aebc8799b5c64d6 Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Sat, 18 Jun 2022 00:19:30 +0900
Subject: [PATCH 04/10] check only the end

---
 clippy_lints/src/copies.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 9d1ca3588b3..f0f2c742034 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -391,12 +391,12 @@ fn contains_acceptable_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
 fn acceptable_macro(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     if let ExprKind::Call(call_expr, _)  = expr.kind
         && let ExprKind::Path(QPath::Resolved(None, path)) = call_expr.kind
-        && macro_backtrace(path.span).any(|macro_call| {
+        && macro_backtrace(path.span).last().map_or(false, |macro_call|
             matches!(
                 &cx.tcx.get_diagnostic_name(macro_call.def_id),
                 Some(sym::todo_macro | sym::unimplemented_macro)
             )
-    }) {
+    ) {
         return true;
     }
 

From f411c18a734a0c4d020ac578ccc3b5b8a7814f8f Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Sat, 18 Jun 2022 17:41:26 +0900
Subject: [PATCH 05/10] check macro_backtrace only

---
 clippy_lints/src/copies.rs | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index f0f2c742034..673744d90b8 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -8,7 +8,7 @@ use clippy_utils::{
 use core::iter;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit;
-use rustc_hir::{BinOpKind, Block, Expr, ExprKind, HirId, QPath, Stmt, StmtKind};
+use rustc_hir::{BinOpKind, Block, Expr, ExprKind, HirId, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::walk_chain;
@@ -389,13 +389,11 @@ fn contains_acceptable_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
 }
 
 fn acceptable_macro(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
-    if let ExprKind::Call(call_expr, _)  = expr.kind
-        && let ExprKind::Path(QPath::Resolved(None, path)) = call_expr.kind
-        && macro_backtrace(path.span).last().map_or(false, |macro_call|
-            matches!(
-                &cx.tcx.get_diagnostic_name(macro_call.def_id),
-                Some(sym::todo_macro | sym::unimplemented_macro)
-            )
+    if macro_backtrace(expr.span).last().map_or(false, |macro_call|
+        matches!(
+            &cx.tcx.get_diagnostic_name(macro_call.def_id),
+            Some(sym::todo_macro | sym::unimplemented_macro)
+        )
     ) {
         return true;
     }

From 7a83809c8c63b135bf5d2d1c9e42d0a94ea5c5ad Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Sat, 18 Jun 2022 17:49:03 +0900
Subject: [PATCH 06/10] check only first statement

---
 clippy_lints/src/copies.rs    | 12 +++++++-----
 tests/ui/if_same_then_else.rs | 32 --------------------------------
 2 files changed, 7 insertions(+), 37 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 673744d90b8..9b64d1631bd 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -372,11 +372,13 @@ fn eq_stmts(
 }
 
 fn contains_acceptable_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
-    for stmt in block.stmts {
-        match stmt.kind {
-            StmtKind::Semi(semi_expr) if acceptable_macro(cx, semi_expr) => return true,
-            _ => {},
-        }
+    if block.stmts.first().map_or(false, |stmt|
+        matches!(
+            stmt.kind,
+            StmtKind::Semi(semi_expr) if acceptable_macro(cx, semi_expr)
+        )
+    ) {
+        return true;
     }
 
     if let Some(block_expr) = block.expr
diff --git a/tests/ui/if_same_then_else.rs b/tests/ui/if_same_then_else.rs
index 2598c2ab426..4110d1a9c01 100644
--- a/tests/ui/if_same_then_else.rs
+++ b/tests/ui/if_same_then_else.rs
@@ -179,38 +179,6 @@ mod issue_8836 {
         } else {
             unimplemented!();
         }
-
-        if true {
-            println!("FOO");
-            todo!();
-        } else {
-            println!("FOO");
-            todo!();
-        }
-
-        if true {
-            println!("FOO");
-            unimplemented!();
-        } else {
-            println!("FOO");
-            unimplemented!();
-        }
-
-        if true {
-            println!("FOO");
-            todo!()
-        } else {
-            println!("FOO");
-            todo!()
-        }
-
-        if true {
-            println!("FOO");
-            unimplemented!()
-        } else {
-            println!("FOO");
-            unimplemented!()
-        }
     }
 }
 

From 040d45e41253aeb6f8efbf3f07f737ea1fb961df Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Sat, 18 Jun 2022 18:24:39 +0900
Subject: [PATCH 07/10] check macro in eq_block

---
 clippy_lints/src/copies.rs    | 33 +----------------------------
 clippy_utils/src/hir_utils.rs | 39 +++++++++++++++++++++++++++++++++--
 2 files changed, 38 insertions(+), 34 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 9b64d1631bd..f6e4d9a4f5c 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -1,5 +1,4 @@
 use clippy_utils::diagnostics::{span_lint_and_note, span_lint_and_then};
-use clippy_utils::macros::macro_backtrace;
 use clippy_utils::source::{first_line_of_span, indent_of, reindent_multiline, snippet, snippet_opt};
 use clippy_utils::{
     eq_expr_value, get_enclosing_block, hash_expr, hash_stmt, if_sequence, is_else_clause, is_lint_allowed,
@@ -13,7 +12,7 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::hygiene::walk_chain;
 use rustc_span::source_map::SourceMap;
-use rustc_span::{sym, BytePos, Span, Symbol};
+use rustc_span::{BytePos, Span, Symbol};
 use std::borrow::Cow;
 
 declare_clippy_lint! {
@@ -197,8 +196,6 @@ fn lint_if_same_then_else(cx: &LateContext<'_>, conds: &[&Expr<'_>], blocks: &[&
         .enumerate()
         .fold(true, |all_eq, (i, &[lhs, rhs])| {
             if eq.eq_block(lhs, rhs)
-                && !contains_acceptable_macro(cx, lhs)
-                && !contains_acceptable_macro(cx, rhs)
                 && !contains_let(conds[i])
                 && conds.get(i + 1).map_or(true, |e| !contains_let(e))
             {
@@ -371,37 +368,9 @@ fn eq_stmts(
         .all(|b| get_stmt(b).map_or(false, |s| eq.eq_stmt(s, stmt)))
 }
 
-fn contains_acceptable_macro(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
-    if block.stmts.first().map_or(false, |stmt|
-        matches!(
-            stmt.kind,
-            StmtKind::Semi(semi_expr) if acceptable_macro(cx, semi_expr)
-        )
-    ) {
-        return true;
-    }
 
-    if let Some(block_expr) = block.expr
-        && acceptable_macro(cx, block_expr)
-    {
-        return true
-    }
 
-    false
-}
 
-fn acceptable_macro(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
-    if macro_backtrace(expr.span).last().map_or(false, |macro_call|
-        matches!(
-            &cx.tcx.get_diagnostic_name(macro_call.def_id),
-            Some(sym::todo_macro | sym::unimplemented_macro)
-        )
-    ) {
-        return true;
-    }
-
-    false
-}
 
 fn scan_block_for_eq(cx: &LateContext<'_>, _conds: &[&Expr<'_>], block: &Block<'_>, blocks: &[&Block<'_>]) -> BlockEq {
     let mut eq = SpanlessEq::new(cx);
diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs
index 39f970dc420..f21098f95f7 100644
--- a/clippy_utils/src/hir_utils.rs
+++ b/clippy_utils/src/hir_utils.rs
@@ -1,5 +1,6 @@
 use crate::consts::constant_simple;
 use crate::source::snippet_opt;
+use crate::macros::macro_backtrace;
 use rustc_ast::ast::InlineAsmTemplatePiece;
 use rustc_data_structures::fx::FxHasher;
 use rustc_hir::def::Res;
@@ -12,7 +13,7 @@ use rustc_hir::{
 use rustc_lexer::{tokenize, TokenKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::TypeckResults;
-use rustc_span::Symbol;
+use rustc_span::{sym, Symbol};
 use std::hash::{Hash, Hasher};
 
 /// Type used to check whether two ast are the same. This is different from the
@@ -65,7 +66,9 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     }
 
     pub fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
-        self.inter_expr().eq_block(left, right)
+        !self.cannot_be_compared_block(left)
+            && !self.cannot_be_compared_block(right)
+            && self.inter_expr().eq_block(left, right)
     }
 
     pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
@@ -83,6 +86,38 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
         self.inter_expr().eq_path_segments(left, right)
     }
+
+    fn cannot_be_compared_block(&mut self, block: &Block<'_>) -> bool {
+        if block.stmts.first().map_or(false, |stmt|
+            matches!(
+                stmt.kind,
+                StmtKind::Semi(semi_expr) if self.should_ignore(semi_expr)
+            )
+        ) {
+            return true;
+        }
+
+        if let Some(block_expr) = block.expr
+            && self.should_ignore(block_expr)
+        {
+            return true
+        }
+
+        false
+    }
+
+    fn should_ignore(&mut self, expr: &Expr<'_>) -> bool {
+        if macro_backtrace(expr.span).last().map_or(false, |macro_call|
+            matches!(
+                &self.cx.tcx.get_diagnostic_name(macro_call.def_id),
+                Some(sym::todo_macro | sym::unimplemented_macro)
+            )
+        ) {
+            return true;
+        }
+
+        false
+    }
 }
 
 pub struct HirEqInterExpr<'a, 'b, 'tcx> {

From 4a02ae9636d57dd4b5b93e5d2688f9eec5de39e9 Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Sat, 18 Jun 2022 18:29:39 +0900
Subject: [PATCH 08/10] cargo dev fmt

---
 clippy_lints/src/copies.rs    |  9 +--------
 clippy_utils/src/hir_utils.rs | 10 +++++-----
 2 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index f6e4d9a4f5c..1deff9684a1 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -195,10 +195,7 @@ fn lint_if_same_then_else(cx: &LateContext<'_>, conds: &[&Expr<'_>], blocks: &[&
         .array_windows::<2>()
         .enumerate()
         .fold(true, |all_eq, (i, &[lhs, rhs])| {
-            if eq.eq_block(lhs, rhs)
-                && !contains_let(conds[i])
-                && conds.get(i + 1).map_or(true, |e| !contains_let(e))
-            {
+            if eq.eq_block(lhs, rhs) && !contains_let(conds[i]) && conds.get(i + 1).map_or(true, |e| !contains_let(e)) {
                 span_lint_and_note(
                     cx,
                     IF_SAME_THEN_ELSE,
@@ -368,10 +365,6 @@ fn eq_stmts(
         .all(|b| get_stmt(b).map_or(false, |s| eq.eq_stmt(s, stmt)))
 }
 
-
-
-
-
 fn scan_block_for_eq(cx: &LateContext<'_>, _conds: &[&Expr<'_>], block: &Block<'_>, blocks: &[&Block<'_>]) -> BlockEq {
     let mut eq = SpanlessEq::new(cx);
     let mut eq = eq.inter_expr();
diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs
index f21098f95f7..97a15108d0c 100644
--- a/clippy_utils/src/hir_utils.rs
+++ b/clippy_utils/src/hir_utils.rs
@@ -1,6 +1,6 @@
 use crate::consts::constant_simple;
-use crate::source::snippet_opt;
 use crate::macros::macro_backtrace;
+use crate::source::snippet_opt;
 use rustc_ast::ast::InlineAsmTemplatePiece;
 use rustc_data_structures::fx::FxHasher;
 use rustc_hir::def::Res;
@@ -88,12 +88,12 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     }
 
     fn cannot_be_compared_block(&mut self, block: &Block<'_>) -> bool {
-        if block.stmts.first().map_or(false, |stmt|
+        if block.stmts.first().map_or(false, |stmt| {
             matches!(
                 stmt.kind,
                 StmtKind::Semi(semi_expr) if self.should_ignore(semi_expr)
             )
-        ) {
+        }) {
             return true;
         }
 
@@ -107,12 +107,12 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     }
 
     fn should_ignore(&mut self, expr: &Expr<'_>) -> bool {
-        if macro_backtrace(expr.span).last().map_or(false, |macro_call|
+        if macro_backtrace(expr.span).last().map_or(false, |macro_call| {
             matches!(
                 &self.cx.tcx.get_diagnostic_name(macro_call.def_id),
                 Some(sym::todo_macro | sym::unimplemented_macro)
             )
-        ) {
+        }) {
             return true;
         }
 

From 46d056e2eb7c5cab767c91383cf7ef1828809fd9 Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Mon, 20 Jun 2022 11:05:40 +0900
Subject: [PATCH 09/10] check last statement

---
 clippy_utils/src/hir_utils.rs |  2 +-
 tests/ui/if_same_then_else.rs | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs
index 97a15108d0c..3eb01bf75a6 100644
--- a/clippy_utils/src/hir_utils.rs
+++ b/clippy_utils/src/hir_utils.rs
@@ -88,7 +88,7 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     }
 
     fn cannot_be_compared_block(&mut self, block: &Block<'_>) -> bool {
-        if block.stmts.first().map_or(false, |stmt| {
+        if block.stmts.last().map_or(false, |stmt| {
             matches!(
                 stmt.kind,
                 StmtKind::Semi(semi_expr) if self.should_ignore(semi_expr)
diff --git a/tests/ui/if_same_then_else.rs b/tests/ui/if_same_then_else.rs
index 4110d1a9c01..2598c2ab426 100644
--- a/tests/ui/if_same_then_else.rs
+++ b/tests/ui/if_same_then_else.rs
@@ -179,6 +179,38 @@ mod issue_8836 {
         } else {
             unimplemented!();
         }
+
+        if true {
+            println!("FOO");
+            todo!();
+        } else {
+            println!("FOO");
+            todo!();
+        }
+
+        if true {
+            println!("FOO");
+            unimplemented!();
+        } else {
+            println!("FOO");
+            unimplemented!();
+        }
+
+        if true {
+            println!("FOO");
+            todo!()
+        } else {
+            println!("FOO");
+            todo!()
+        }
+
+        if true {
+            println!("FOO");
+            unimplemented!()
+        } else {
+            println!("FOO");
+            unimplemented!()
+        }
     }
 }
 

From 39ffda014debd9d1d4126a8996d39af934fe8d94 Mon Sep 17 00:00:00 2001
From: kyoto7250 <50972773+kyoto7250@users.noreply.github.com>
Date: Mon, 20 Jun 2022 11:14:52 +0900
Subject: [PATCH 10/10] check macro in HitEqInterExpr

---
 clippy_utils/src/hir_utils.rs | 71 ++++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 35 deletions(-)

diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs
index 3eb01bf75a6..46b615c04f3 100644
--- a/clippy_utils/src/hir_utils.rs
+++ b/clippy_utils/src/hir_utils.rs
@@ -66,9 +66,7 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     }
 
     pub fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
-        !self.cannot_be_compared_block(left)
-            && !self.cannot_be_compared_block(right)
-            && self.inter_expr().eq_block(left, right)
+        self.inter_expr().eq_block(left, right)
     }
 
     pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
@@ -86,38 +84,6 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
         self.inter_expr().eq_path_segments(left, right)
     }
-
-    fn cannot_be_compared_block(&mut self, block: &Block<'_>) -> bool {
-        if block.stmts.last().map_or(false, |stmt| {
-            matches!(
-                stmt.kind,
-                StmtKind::Semi(semi_expr) if self.should_ignore(semi_expr)
-            )
-        }) {
-            return true;
-        }
-
-        if let Some(block_expr) = block.expr
-            && self.should_ignore(block_expr)
-        {
-            return true
-        }
-
-        false
-    }
-
-    fn should_ignore(&mut self, expr: &Expr<'_>) -> bool {
-        if macro_backtrace(expr.span).last().map_or(false, |macro_call| {
-            matches!(
-                &self.cx.tcx.get_diagnostic_name(macro_call.def_id),
-                Some(sym::todo_macro | sym::unimplemented_macro)
-            )
-        }) {
-            return true;
-        }
-
-        false
-    }
 }
 
 pub struct HirEqInterExpr<'a, 'b, 'tcx> {
@@ -156,6 +122,9 @@ impl HirEqInterExpr<'_, '_, '_> {
 
     /// Checks whether two blocks are the same.
     fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
+        if self.cannot_be_compared_block(left) || self.cannot_be_compared_block(right) {
+            return false;
+        }
         match (left.stmts, left.expr, right.stmts, right.expr) {
             ([], None, [], None) => {
                 // For empty blocks, check to see if the tokens are equal. This will catch the case where a macro
@@ -206,6 +175,38 @@ impl HirEqInterExpr<'_, '_, '_> {
         }
     }
 
+    fn cannot_be_compared_block(&mut self, block: &Block<'_>) -> bool {
+        if block.stmts.last().map_or(false, |stmt| {
+            matches!(
+                stmt.kind,
+                StmtKind::Semi(semi_expr) if self.should_ignore(semi_expr)
+            )
+        }) {
+            return true;
+        }
+
+        if let Some(block_expr) = block.expr
+            && self.should_ignore(block_expr)
+        {
+            return true
+        }
+
+        false
+    }
+
+    fn should_ignore(&mut self, expr: &Expr<'_>) -> bool {
+        if macro_backtrace(expr.span).last().map_or(false, |macro_call| {
+            matches!(
+                &self.inner.cx.tcx.get_diagnostic_name(macro_call.def_id),
+                Some(sym::todo_macro | sym::unimplemented_macro)
+            )
+        }) {
+            return true;
+        }
+
+        false
+    }
+
     pub fn eq_array_length(&mut self, left: ArrayLen, right: ArrayLen) -> bool {
         match (left, right) {
             (ArrayLen::Infer(..), ArrayLen::Infer(..)) => true,