fix: collapsible_if FP on block stmt before expr

Author: profetia

clippy_lints/src/collapsible_if.rs

@@ -1,9 +1,10 @@
 use clippy_config::Conf;
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::peel_blocks_with_stmt;
 use clippy_utils::source::{IntoSpan as _, SpanRangeExt, snippet, snippet_block, snippet_block_with_applicability};
 use rustc_ast::BinOpKind;
 use rustc_errors::Applicability;
-use rustc_hir::{Block, Expr, ExprKind, StmtKind};
+use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::impl_lint_pass;
@@ -90,9 +91,10 @@ impl CollapsibleIf {
         }
     }
 
-    fn check_collapsible_else_if(cx: &LateContext<'_>, then_span: Span, else_block: &Block<'_>) {
+    fn check_collapsible_else_if(cx: &LateContext<'_>, then_span: Span, else_block: &Expr<'_>) {
         if !block_starts_with_comment(cx, else_block)
-            && let Some(else_) = expr_block(else_block)
+            && let else_ = peel_blocks_with_stmt(else_block)
+            && else_.hir_id != else_block.hir_id
             && cx.tcx.hir_attrs(else_.hir_id).is_empty()
             && !else_.span.from_expansion()
             && let ExprKind::If(..) = else_.kind
@@ -123,8 +125,9 @@ impl CollapsibleIf {
         }
     }
 
-    fn check_collapsible_if_if(&self, cx: &LateContext<'_>, expr: &Expr<'_>, check: &Expr<'_>, then: &Block<'_>) {
-        if let Some(inner) = expr_block(then)
+    fn check_collapsible_if_if(&self, cx: &LateContext<'_>, expr: &Expr<'_>, check: &Expr<'_>, then: &Expr<'_>) {
+        let inner = peel_blocks_with_stmt(then);
+        if inner.hir_id != then.hir_id
             && cx.tcx.hir_attrs(inner.hir_id).is_empty()
             && let ExprKind::If(check_inner, _, None) = &inner.kind
             && self.eligible_condition(check_inner)
@@ -176,43 +179,27 @@ impl LateLintPass<'_> for CollapsibleIf {
             && !expr.span.from_expansion()
         {
             if let Some(else_) = else_
-                && let ExprKind::Block(else_, None) = else_.kind
+                && let ExprKind::Block(_, None) = else_.kind
             {
                 Self::check_collapsible_else_if(cx, then.span, else_);
             } else if else_.is_none()
                 && self.eligible_condition(cond)
-                && let ExprKind::Block(then, None) = then.kind
+                && let ExprKind::Block(_, None) = then.kind
             {
                 self.check_collapsible_if_if(cx, expr, cond, then);
             }
         }
     }
 }
 
-fn block_starts_with_comment(cx: &LateContext<'_>, block: &Block<'_>) -> bool {
+fn block_starts_with_comment(cx: &LateContext<'_>, block: &Expr<'_>) -> bool {
     // We trim all opening braces and whitespaces and then check if the next string is a comment.
     let trimmed_block_text = snippet_block(cx, block.span, "..", None)
         .trim_start_matches(|c: char| c.is_whitespace() || c == '{')
         .to_owned();
     trimmed_block_text.starts_with("//") || trimmed_block_text.starts_with("/*")
 }
 
-/// If `block` is a block with either one expression or a statement containing an expression,
-/// return the expression. We don't peel blocks recursively, as extra blocks might be intentional.
-fn expr_block<'tcx>(block: &Block<'tcx>) -> Option<&'tcx Expr<'tcx>> {
-    match block.stmts {
-        [] => block.expr,
-        [stmt] => {
-            if let StmtKind::Semi(expr) = stmt.kind {
-                Some(expr)
-            } else {
-                None
-            }
-        },
-        _ => None,
-    }
-}
-
 /// If the expression is a `||`, suggest parentheses around it.
 fn parens_around(expr: &Expr<'_>) -> Vec<(Span, String)> {
     if let ExprKind::Binary(op, _, _) = expr.peel_drop_temps().kind

tests/ui/collapsible_if.fixed

@@ -162,3 +162,14 @@ fn layout_check() -> u32 {
     ; 3
     //~^^^^^ collapsible_if
 }
+
+fn issue14722() {
+    let x = if true {
+        Some(1)
+    } else {
+        if true {
+            println!("Some debug information");
+        };
+        None
+    };
+}

tests/ui/collapsible_if.rs

@@ -172,3 +172,14 @@ fn layout_check() -> u32 {
     }; 3
     //~^^^^^ collapsible_if
 }
+
+fn issue14722() {
+    let x = if true {
+        Some(1)
+    } else {
+        if true {
+            println!("Some debug information");
+        };
+        None
+    };
+}