diff --git a/internal/repo/patch.go b/internal/repo/patch.go
index 32e324b..6f2e3c6 100644
--- a/internal/repo/patch.go
+++ b/internal/repo/patch.go
@@ -665,9 +665,9 @@ func splitByAnchor(lines []string, current hunk) []hunk {
 	return parts
 }
 
-// locate finds the one place block occurs in lines. A short block that
-// appears more than once is ambiguous, and picking one would risk editing
-// the wrong part of the file, so it is refused instead.
+// locate finds the one place block occurs in lines. A block that appears
+// more than once is ambiguous, however long it is, and picking one would
+// risk editing the wrong part of the file, so it is refused instead.
 func locate(lines, block []string) (int, *HunkError) {
 	matches := findAll(lines, block, func(a, b string) bool { return a == b })
 	if len(matches) == 0 {
@@ -720,7 +720,7 @@ func locate(lines, block []string) (int, *HunkError) {
 			detail += fmt.Sprintf("\n\nthe closest match is at line %d, where it differs:\n  expected: %q\n  in file:  %q", at, expected, found)
 		}
 		return 0, &HunkError{Reason: reason, Expected: expected, Found: found, Detail: detail, Block: block}
-	case len(matches) > 1 && len(block) < 3:
+	case len(matches) > 1:
 		reason := fmt.Sprintf("this hunk's lines appear %d times, too ambiguous to place", len(matches))
 		return 0, &HunkError{Reason: reason, Detail: fmt.Sprintf("%s:\n%s%s", reason, preview(block), disambiguate(lines, matches, block))}
 	default:
diff --git a/internal/repo/patch_test.go b/internal/repo/patch_test.go
index c080b66..da08c5d 100644
--- a/internal/repo/patch_test.go
+++ b/internal/repo/patch_test.go
@@ -147,6 +147,34 @@ func TestAmbiguousHunkErrorPointsAtEachMatch(t *testing.T) {
 	}
 }
 
+func TestApplyIsRefusedWhenALongerHunkIsAmbiguous(t *testing.T) {
+	// Length does not make a block unique. Go's three-line error check
+	// appears in almost every function, and a hunk made of exactly that
+	// could mean any of them: placing it at the first one edits a function
+	// nobody asked about and reports the patch as applied.
+	root := t.TempDir()
+	original := "func a() error {\n\tif err != nil {\n\t\treturn err\n\t}\n\treturn nil\n}\n\n" +
+		"func b() error {\n\tif err != nil {\n\t\treturn err\n\t}\n\treturn nil\n}\n"
+	writeFile(t, root, "a.go", original)
+	repository := &Repository{Root: root}
+	patch := "@a.go\n" +
+		" \tif err != nil {\n" +
+		"-\t\treturn err\n" +
+		"+\t\treturn fmt.Errorf(\"b: %w\", err)\n" +
+		" \t}\n"
+	err := repository.Apply(patch)
+	if err == nil {
+		t.Fatal("expected a hunk that matches two places to be refused")
+	}
+	if !strings.Contains(err.Error(), "ambiguous") {
+		t.Fatalf("err = %v, want it to explain the ambiguity", err)
+	}
+	content, _ := os.ReadFile(filepath.Join(root, "a.go"))
+	if string(content) != original {
+		t.Fatalf("file was modified despite the refusal: %q", content)
+	}
+}
+
 func TestApplyLeavesFilesAloneWhenAHunkCannotBePlaced(t *testing.T) {
 	patch := "--- a/index.html\n+++ b/index.html\n@@ -1,1 +1,1 @@\n" +
 		"-  <title>Something Else Entirely</title>\n" +