1 files changed, 129 insertions, 0 deletions
diff --git a/src/tools/rustfmt/tests/target/let_chains.rs b/src/tools/rustfmt/tests/target/let_chains.rs
new file mode 100644
index 000000000..1ceecac8a
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/let_chains.rs
@@ -0,0 +1,129 @@
+fn main() {
+    if let x = x
+        && x
+    {}
+
+    if xxx && let x = x {}
+
+    if aaaaaaaaaaaaaaaaaaaaa
+        && aaaaaaaaaaaaaaa
+        && aaaaaaaaa
+        && let Some(x) = xxxxxxxxxxxx
+        && aaaaaaa
+        && let None = aaaaaaaaaa
+    {}
+
+    if aaaaaaaaaaaaaaaaaaaaa
+        && aaaaaaaaaaaaaaa
+        && aaaaaaaaa
+        && let Some(x) = xxxxxxxxxxxx
+        && aaaaaaa
+        && let None = aaaaaaaaaa
+    {}
+
+    if let Some(Struct { x: TS(1, 2) }) = path::to::<_>(hehe)
+        && let [Simple, people] = /* get ready */
+            create_universe(/* hi */ GreatPowers)
+                .initialize_badminton()
+                .populate_swamps()
+        && let everybody = (Loops {
+            hi, /*hi*/
+            ..loopy()
+        })
+        && summons::triumphantly()
+    {
+        todo!()
+    }
+
+    if let XXXXXXXXX {
+        xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx,
+        yyyyyyyyyyyyy,
+        zzzzzzzzzzzzz,
+    } = xxxxxxx()
+        && let Foo = bar()
+    {
+        todo!()
+    }
+}
+
+fn test_single_line_let_chain() {
+    // first item in let-chain is an ident
+    if a && let Some(b) = foo() {}
+
+    // first item in let-chain is a unary ! with an ident
+    let unary_not = if !from_hir_call && let Some(p) = parent {};
+
+    // first item in let-chain is a unary * with an ident
+    let unary_deref = if *some_deref && let Some(p) = parent {};
+
+    // first item in let-chain is a unary - (neg) with an ident
+    let unary_neg = if -some_ident && let Some(p) = parent {};
+
+    // first item in let-chain is a try (?) with an ident
+    let try_ = if some_try? && let Some(p) = parent {};
+
+    // first item in let-chain is an ident wrapped in parens
+    let in_parens = if (some_ident) && let Some(p) = parent {};
+
+    // first item in let-chain is a ref & with an ident
+    let _ref = if &some_ref && let Some(p) = parent {};
+
+    // first item in let-chain is a ref &mut with an ident
+    let mut_ref = if &mut some_ref && let Some(p) = parent {};
+
+    // chain unary ref and try
+    let chain_of_unary_ref_and_try = if !&*some_ref? && let Some(p) = parent {};
+}
+
+fn test_multi_line_let_chain() {
+    // Can only single line the let-chain if the first item is an ident
+    if let Some(x) = y
+        && a
+    {}
+
+    // More than one let-chain must be formatted on multiple lines
+    if let Some(x) = y
+        && let Some(a) = b
+    {}
+
+    // The ident isn't long enough so we don't wrap the first let-chain
+    if a && let Some(x) = y
+        && let Some(a) = b
+    {}
+
+    // The ident is long enough so both let-chains are wrapped
+    if aaa
+        && let Some(x) = y
+        && let Some(a) = b
+    {}
+
+    // function call
+    if a()
+        && let Some(x) = y
+    {}
+
+    // bool literal
+    if true
+        && let Some(x) = y
+    {}
+
+    // cast to a bool
+    if 1 as bool
+        && let Some(x) = y
+    {}
+
+    // matches! macro call
+    if matches!(a, some_type)
+        && let Some(x) = y
+    {}
+
+    // block expression returning bool
+    if { true }
+        && let Some(x) = y
+    {}
+
+    // field access
+    if a.x
+        && let Some(x) = y
+    {}
+}