From 0b6565c12aed9084b741cfda033d6bccf27c1efe Mon Sep 17 00:00:00 2001
From: parrrate <alisa@parrrate.com>
Date: Fri, 12 Sep 2025 18:33:45 +0000
Subject: [PATCH] `multiple_blanket.md`

---
 .gitignore                        | 13 +++++++
 Cargo.toml                        |  8 ++++
 src/SUMMARY.md                    |  1 +
 src/exercises/multiple_blanket.md | 64 +++++++++++++++++++++++++++++++
 src/lib.rs                        | 14 +++++++
 5 files changed, 100 insertions(+)
 create mode 100644 Cargo.toml
 create mode 100644 src/exercises/multiple_blanket.md
 create mode 100644 src/lib.rs

diff --git a/.gitignore b/.gitignore
index 7585238..ef05725 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,14 @@
 book
+
+
+# Added by cargo
+
+/target
+
+
+# Added by cargo
+#
+# already existing elements were commented out
+
+#/target
+/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..d51cd24
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "exercises"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index 7390c82..d6e08d3 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -1,3 +1,4 @@
 # Summary
 
 - [Chapter 1](./chapter_1.md)
+  - [`A`/`A1`/`A2`](./exercises/multiple_blanket.md)
diff --git a/src/exercises/multiple_blanket.md b/src/exercises/multiple_blanket.md
new file mode 100644
index 0000000..bc601f0
--- /dev/null
+++ b/src/exercises/multiple_blanket.md
@@ -0,0 +1,64 @@
+```rust
+trait A {
+    fn a_ref(&self) -> u64;
+    fn a_mut(&mut self) -> bool;
+    fn a_move(self) -> Self;
+}
+
+fn test(x: impl A) {
+    x.a_ref();
+    let mut x = x.a_move();
+    x.a_mut();
+}
+
+fn test1(x: impl A1) {
+    test(x)
+}
+
+fn test2(x: impl A2) {
+    test(x)
+}
+# use std::marker::PhantomData;
+# trait Wrapper<T>: Sized {}
+# #[repr(transparent)]
+# struct Wrapped<T, V: ?Sized>(PhantomData<V>, T);
+# trait AProxy {
+# type T;
+# fn ap_ref(t: &Self::T) -> u64;
+# fn ap_mut(t: &mut Self::T) -> bool;
+# fn ap_move(t: Self::T) -> Self::T;
+# }
+# trait AWrapper: Wrapper<Self::AWrapped> { type AWrapped; }
+# impl<T: AWrapper> A for T where T::AWrapped: AProxy<T = T>,
+# {
+# fn a_ref(&self) -> u64 { <T::AWrapped as AProxy>::ap_ref(self) }
+# fn a_mut(&mut self) -> bool { <T::AWrapped as AProxy>::ap_mut(self) }
+# fn a_move(self) -> Self { <T::AWrapped as AProxy>::ap_move(self) }
+# }
+# trait A1: AWrapper<AWrapped = Aw1<Self>> {
+# fn a1_ref(&self) -> u64;
+# fn a1_mut(&mut self) -> bool;
+# fn a1_move(self) -> Self;
+# }
+# trait A2: AWrapper<AWrapped = Aw2<Self>> {
+# fn a2_ref(&self) -> u64;
+# fn a2_mut(&mut self) -> bool;
+# fn a2_move(self) -> Self;
+# }
+# struct Av1;
+# struct Av2;
+# type Aw1<T> = Wrapped<T, Av1>;
+# type Aw2<T> = Wrapped<T, Av2>;
+# impl<T: ?Sized + A1> AProxy for Aw1<T> {
+# type T = T;
+# fn ap_ref(t: &Self::T) -> u64 { t.a1_ref() }
+# fn ap_mut(t: &mut Self::T) -> bool { t.a1_mut() }
+# fn ap_move(t: Self::T) -> Self::T { t.a1_move() }
+# }
+# impl<T: ?Sized + A2> AProxy for Aw2<T> {
+# type T = T;
+# fn ap_ref(t: &Self::T) -> u64 { t.a2_ref() }
+# fn ap_mut(t: &mut Self::T) -> bool { t.a2_mut() }
+# fn ap_move(t: Self::T) -> Self::T { t.a2_move() }
+# }
+```
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..7d12d9a
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,14 @@
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn it_works() {
+        let result = add(2, 2);
+        assert_eq!(result, 4);
+    }
+}