Rollup merge of #92402 - pr2502:while-let-typo, r=oli-obk

Suggest while let x = y when encountering while x = y

Extends #75931 to also detect where the `let` might be missing from `while let` expressions.

2 files changed, 54 insertions, 0 deletions

diff --git a/src/test/ui/suggestions/while-let-typo.rs b/src/test/ui/suggestions/while-let-typo.rs
new file mode 100644
index 00000000000..dbbcdee3c19
--- /dev/null
+++ b/src/test/ui/suggestions/while-let-typo.rs
@@ -0,0 +1,9 @@
+fn main() {
+    let foo = Some(0);
+    let bar = None;
+    while Some(x) = foo {} //~ ERROR cannot find value `x` in this scope
+    while Some(foo) = bar {}
+    while 3 = foo {} //~ ERROR mismatched types
+    while Some(3) = foo {} //~ ERROR invalid left-hand side of assignment
+    while x = 5 {} //~ ERROR cannot find value `x` in this scope
+}
diff --git a/src/test/ui/suggestions/while-let-typo.stderr b/src/test/ui/suggestions/while-let-typo.stderr
new file mode 100644
index 00000000000..7cc2ed3149b
--- /dev/null
+++ b/src/test/ui/suggestions/while-let-typo.stderr
@@ -0,0 +1,45 @@
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/while-let-typo.rs:4:16
+   |
+LL |     while Some(x) = foo {}
+   |                ^ not found in this scope
+   |
+help: you might have meant to use pattern matching
+   |
+LL |     while let Some(x) = foo {}
+   |           +++
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/while-let-typo.rs:8:11
+   |
+LL |     while x = 5 {}
+   |           ^ not found in this scope
+   |
+help: you might have meant to use pattern matching
+   |
+LL |     while let x = 5 {}
+   |           +++
+
+error[E0308]: mismatched types
+  --> $DIR/while-let-typo.rs:6:11
+   |
+LL |     while 3 = foo {}
+   |           ^^^^^^^ expected `bool`, found `()`
+
+error[E0070]: invalid left-hand side of assignment
+  --> $DIR/while-let-typo.rs:7:19
+   |
+LL |     while Some(3) = foo {}
+   |                -  ^
+   |                |
+   |                cannot assign to this expression
+   |
+help: you might have meant to use pattern destructuring
+   |
+LL |     while let Some(3) = foo {}
+   |           +++
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0070, E0308, E0425.
+For more information about an error, try `rustc --explain E0070`.