diff --git a/clippy_lints/src/entry.rs b/clippy_lints/src/entry.rs
index a5ec6777b434..6bfaffdddf4d 100644
--- a/clippy_lints/src/entry.rs
+++ b/clippy_lints/src/entry.rs
@@ -4,7 +4,7 @@ use clippy_utils::ty::is_copy;
 use clippy_utils::visitors::for_each_expr;
 use clippy_utils::{
     SpanlessEq, can_move_expr_to_closure_no_visit, higher, is_expr_final_block_expr, is_expr_used_or_unified,
-    peel_hir_expr_while,
+    peel_hir_expr_while, span_contains_non_whitespace,
 };
 use core::fmt::{self, Write};
 use rustc_errors::Applicability;
@@ -13,7 +13,7 @@ use rustc_hir::intravisit::{Visitor, walk_body, walk_expr};
 use rustc_hir::{Block, Expr, ExprKind, HirId, Pat, Stmt, StmtKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
-use rustc_span::{DUMMY_SP, Span, SyntaxContext, sym};
+use rustc_span::{BytePos, DUMMY_SP, Pos, Span, SyntaxContext, sym};
 use std::ops::ControlFlow;
 
 declare_clippy_lint! {
@@ -166,7 +166,11 @@ impl<'tcx> LateLintPass<'tcx> for HashMapPass {
                     "if let {}::{entry_kind} = {map_str}.entry({key_str}) {body_str}",
                     map_ty.entry_path(),
                 ))
-            } else if let Some(insertion) = then_search.as_single_insertion() {
+            } else if let Some(insertion) = then_search.as_single_insertion()
+                && let span_in_between = then_expr.span.shrink_to_lo().between(insertion.call.span)
+                && let span_in_between = span_in_between.with_lo(span_in_between.lo() + BytePos::from_usize(1))
+                && !span_contains_non_whitespace(cx, span_in_between, true)
+            {
                 let value_str = snippet_with_context(cx, insertion.value.span, then_expr.span.ctxt(), "..", &mut app).0;
                 if contains_expr.negated {
                     if insertion.value.can_have_side_effects() {
diff --git a/tests/ui/entry.fixed b/tests/ui/entry.fixed
index f2df9f0204ea..c621c059c5ab 100644
--- a/tests/ui/entry.fixed
+++ b/tests/ui/entry.fixed
@@ -249,3 +249,13 @@ mod issue14449 {
 }
 
 fn main() {}
+
+fn issue15781(m: &mut std::collections::HashMap<i32, i32>, k: i32, v: i32) {
+    fn very_important_fn() {}
+    m.entry(k).or_insert_with(|| {
+        //~^ map_entry
+        #[cfg(test)]
+        very_important_fn();
+        v
+    });
+}
diff --git a/tests/ui/entry.rs b/tests/ui/entry.rs
index 166eea417ac2..e60215116950 100644
--- a/tests/ui/entry.rs
+++ b/tests/ui/entry.rs
@@ -255,3 +255,13 @@ mod issue14449 {
 }
 
 fn main() {}
+
+fn issue15781(m: &mut std::collections::HashMap<i32, i32>, k: i32, v: i32) {
+    fn very_important_fn() {}
+    if !m.contains_key(&k) {
+        //~^ map_entry
+        #[cfg(test)]
+        very_important_fn();
+        m.insert(k, v);
+    }
+}
diff --git a/tests/ui/entry.stderr b/tests/ui/entry.stderr
index 009b78d29073..22fbc959782a 100644
--- a/tests/ui/entry.stderr
+++ b/tests/ui/entry.stderr
@@ -246,5 +246,26 @@ LL +         e.insert(42);
 LL +     }
    |
 
-error: aborting due to 11 previous errors
+error: usage of `contains_key` followed by `insert` on a `HashMap`
+  --> tests/ui/entry.rs:261:5
+   |
+LL | /     if !m.contains_key(&k) {
+LL | |
+LL | |         #[cfg(test)]
+LL | |         very_important_fn();
+LL | |         m.insert(k, v);
+LL | |     }
+   | |_____^
+   |
+help: try
+   |
+LL ~     m.entry(k).or_insert_with(|| {
+LL +
+LL +         #[cfg(test)]
+LL +         very_important_fn();
+LL +         v
+LL +     });
+   |
+
+error: aborting due to 12 previous errors