Fix demorgan applicable on pattern conditional

Example
---
```rust
fn f() {
    if let 1 = 1 &&$0 true { }
}
```

**Before this PR**

```rust
fn f() {
    if !(!let 1 = 1 || false) { }
}
```

**After this PR**

Assist not applicable

Author: A4-Tacks

crates/ide-assists/src/handlers/apply_demorgan.rs

@@ -3,7 +3,7 @@ use std::collections::VecDeque;
 use ide_db::{
     assists::GroupLabel,
     famous_defs::FamousDefs,
-    syntax_helpers::node_ext::{for_each_tail_expr, walk_expr},
+    syntax_helpers::node_ext::{for_each_tail_expr, is_pattern_cond, walk_expr},
 };
 use syntax::{
     NodeOrToken, SyntaxKind, T,
@@ -69,6 +69,10 @@ pub(crate) fn apply_demorgan(acc: &mut Assists, ctx: &AssistContext<'_>) -> Opti
         }
     }
 
+    if is_pattern_cond(bin_expr.clone().into()) {
+        return None;
+    }
+
     let op = bin_expr.op_kind()?;
     let (inv_token, prec) = match op {
         ast::BinaryOp::LogicOp(ast::LogicOp::And) => (SyntaxKind::PIPE2, ExprPrecedence::LOr),
@@ -375,6 +379,16 @@ fn f() { !(S <= S || S < S) }
         )
     }
 
+    #[test]
+    fn demorgan_doesnt_handles_pattern() {
+        check_assist_not_applicable(
+            apply_demorgan,
+            r#"
+fn f() { if let 1 = 1 &&$0 true { } }
+"#,
+        );
+    }
+
     #[test]
     fn demorgan_on_not() {
         check_assist(