Rollup merge of #111841 - matthewjasper:validate-match-guards, r=compiler-errors

Run AST validation on match guards correctly

AST validation was being skipped on match guards other than `if let` guards.

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -736,11 +736,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         this.visit_expr(&arm.body);
                         this.visit_pat(&arm.pat);
                         walk_list!(this, visit_attribute, &arm.attrs);
-                        if let Some(guard) = &arm.guard && let ExprKind::Let(_, guard_expr, _) = &guard.kind {
+                        if let Some(guard) = &arm.guard {
                             this.with_let_management(None, |this, _| {
-                                this.visit_expr(guard_expr)
+                                this.visit_expr(guard)
                             });
-                            return;
                         }
                     }
                 }

compiler/rustc_mir_build/src/build/expr/as_operand.rs

@@ -118,7 +118,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let category = Category::of(&expr.kind).unwrap();
         debug!(?category, ?expr.kind);
         match category {
-            Category::Constant if let NeedsTemporary::No = needs_temporary || !expr.ty.needs_drop(this.tcx, this.param_env) => {
+            Category::Constant
+                if matches!(needs_temporary, NeedsTemporary::No)
+                    || !expr.ty.needs_drop(this.tcx, this.param_env) =>
+            {
                 let constant = this.as_constant(expr);
                 block.and(Operand::Constant(Box::new(constant)))
             }
@@ -126,7 +129,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let operand = unpack!(block = this.as_temp(block, scope, expr, Mutability::Mut));
                 // Overwrite temp local info if we have something more interesting to record.
                 if !matches!(local_info, LocalInfo::Boring) {
-                    let decl_info = this.local_decls[operand].local_info.as_mut().assert_crate_local();
+                    let decl_info =
+                        this.local_decls[operand].local_info.as_mut().assert_crate_local();
                     if let LocalInfo::Boring | LocalInfo::BlockTailTemp(_) = **decl_info {
                         **decl_info = local_info;
                     }

tests/ui/rfc-2294-if-let-guard/feature-gate.rs

@@ -10,10 +10,12 @@ fn _if_let_guard() {
         () if (let 0 = 1) => {}
         //~^ ERROR `let` expressions in this position are unstable
         //~| ERROR expected expression, found `let` statement
+        //~| ERROR `let` expressions are not supported here
 
         () if (((let 0 = 1))) => {}
         //~^ ERROR `let` expressions in this position are unstable
         //~| ERROR expected expression, found `let` statement
+        //~| ERROR `let` expressions are not supported here
 
         () if true && let 0 = 1 => {}
         //~^ ERROR `if let` guards are experimental
@@ -26,16 +28,20 @@ fn _if_let_guard() {
         () if (let 0 = 1) && true => {}
         //~^ ERROR `let` expressions in this position are unstable
         //~| ERROR expected expression, found `let` statement
+        //~| ERROR `let` expressions are not supported here
 
         () if true && (let 0 = 1) => {}
         //~^ ERROR `let` expressions in this position are unstable
         //~| ERROR expected expression, found `let` statement
+        //~| ERROR `let` expressions are not supported here
 
         () if (let 0 = 1) && (let 0 = 1) => {}
         //~^ ERROR `let` expressions in this position are unstable
         //~| ERROR `let` expressions in this position are unstable
         //~| ERROR expected expression, found `let` statement
         //~| ERROR expected expression, found `let` statement
+        //~| ERROR `let` expressions are not supported here
+        //~| ERROR `let` expressions are not supported here
 
         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
         //~^ ERROR `if let` guards are experimental
@@ -47,6 +53,10 @@ fn _if_let_guard() {
         //~| ERROR expected expression, found `let` statement
         //~| ERROR expected expression, found `let` statement
         //~| ERROR expected expression, found `let` statement
+        //~| ERROR `let` expressions are not supported here
+        //~| ERROR `let` expressions are not supported here
+        //~| ERROR `let` expressions are not supported here
+
 
         () if let Range { start: _, end: _ } = (true..true) && false => {}
         //~^ ERROR `if let` guards are experimental
@@ -68,9 +78,11 @@ fn _macros() {
     use_expr!((let 0 = 1 && 0 == 0));
     //~^ ERROR `let` expressions in this position are unstable
     //~| ERROR expected expression, found `let` statement
+    //~| ERROR `let` expressions are not supported here
     use_expr!((let 0 = 1));
     //~^ ERROR `let` expressions in this position are unstable
     //~| ERROR expected expression, found `let` statement
+    //~| ERROR `let` expressions are not supported here
     match () {
         #[cfg(FALSE)]
         () if let 0 = 1 => {}

tests/ui/rfc-2294-if-let-guard/feature-gate.stderr

@@ -5,67 +5,67 @@ LL |         () if (let 0 = 1) => {}
    |                ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:14:18
+  --> $DIR/feature-gate.rs:15:18
    |
 LL |         () if (((let 0 = 1))) => {}
    |                  ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:26:16
+  --> $DIR/feature-gate.rs:28:16
    |
 LL |         () if (let 0 = 1) && true => {}
    |                ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:30:24
+  --> $DIR/feature-gate.rs:33:24
    |
 LL |         () if true && (let 0 = 1) => {}
    |                        ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:34:16
+  --> $DIR/feature-gate.rs:38:16
    |
 LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    |                ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:34:31
+  --> $DIR/feature-gate.rs:38:31
    |
 LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    |                               ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:40:42
+  --> $DIR/feature-gate.rs:46:42
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                                          ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:40:55
+  --> $DIR/feature-gate.rs:46:55
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                                                       ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:40:68
+  --> $DIR/feature-gate.rs:46:68
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                                                                    ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:68:16
+  --> $DIR/feature-gate.rs:78:16
    |
 LL |     use_expr!((let 0 = 1 && 0 == 0));
    |                ^^^
 
 error: expected expression, found `let` statement
-  --> $DIR/feature-gate.rs:71:16
+  --> $DIR/feature-gate.rs:82:16
    |
 LL |     use_expr!((let 0 = 1));
    |                ^^^
 
 error: no rules expected the token `let`
-  --> $DIR/feature-gate.rs:80:15
+  --> $DIR/feature-gate.rs:92:15
    |
 LL |     macro_rules! use_expr {
    |     --------------------- when calling this macro
@@ -74,11 +74,154 @@ LL |     use_expr!(let 0 = 1);
    |               ^^^ no rules expected this token in macro call
    |
 note: while trying to match meta-variable `$e:expr`
-  --> $DIR/feature-gate.rs:61:10
+  --> $DIR/feature-gate.rs:71:10
    |
 LL |         ($e:expr) => {
    |          ^^^^^^^
 
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:10:16
+   |
+LL |         () if (let 0 = 1) => {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:10:16
+   |
+LL |         () if (let 0 = 1) => {}
+   |                ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:15:18
+   |
+LL |         () if (((let 0 = 1))) => {}
+   |                  ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:15:18
+   |
+LL |         () if (((let 0 = 1))) => {}
+   |                  ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:28:16
+   |
+LL |         () if (let 0 = 1) && true => {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:28:16
+   |
+LL |         () if (let 0 = 1) && true => {}
+   |                ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:33:24
+   |
+LL |         () if true && (let 0 = 1) => {}
+   |                        ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:33:24
+   |
+LL |         () if true && (let 0 = 1) => {}
+   |                        ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:38:16
+   |
+LL |         () if (let 0 = 1) && (let 0 = 1) => {}
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:38:16
+   |
+LL |         () if (let 0 = 1) && (let 0 = 1) => {}
+   |                ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:38:31
+   |
+LL |         () if (let 0 = 1) && (let 0 = 1) => {}
+   |                               ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:38:31
+   |
+LL |         () if (let 0 = 1) && (let 0 = 1) => {}
+   |                               ^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:46:42
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                          ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:46:42
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:46:55
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                                       ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:46:42
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:46:68
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                                                    ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:46:42
+   |
+LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
+   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:78:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:78:16
+   |
+LL |     use_expr!((let 0 = 1 && 0 == 0));
+   |                ^^^^^^^^^^^^^^^^^^^
+
+error: `let` expressions are not supported here
+  --> $DIR/feature-gate.rs:82:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `let`s wrapped in parentheses are not supported in a context with let chains
+  --> $DIR/feature-gate.rs:82:16
+   |
+LL |     use_expr!((let 0 = 1));
+   |                ^^^^^^^^^
+
 error[E0658]: `if let` guards are experimental
   --> $DIR/feature-gate.rs:7:12
    |
@@ -90,7 +233,7 @@ LL |         () if let 0 = 1 => {}
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
 error[E0658]: `if let` guards are experimental
-  --> $DIR/feature-gate.rs:18:12
+  --> $DIR/feature-gate.rs:20:12
    |
 LL |         () if true && let 0 = 1 => {}
    |            ^^^^^^^^^^^^^^^^^^^^
@@ -100,7 +243,7 @@ LL |         () if true && let 0 = 1 => {}
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
 error[E0658]: `if let` guards are experimental
-  --> $DIR/feature-gate.rs:22:12
+  --> $DIR/feature-gate.rs:24:12
    |
 LL |         () if let 0 = 1 && true => {}
    |            ^^^^^^^^^^^^^^^^^^^^
@@ -110,7 +253,7 @@ LL |         () if let 0 = 1 && true => {}
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
 error[E0658]: `if let` guards are experimental
-  --> $DIR/feature-gate.rs:40:12
+  --> $DIR/feature-gate.rs:46:12
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -120,7 +263,7 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
 error[E0658]: `if let` guards are experimental
-  --> $DIR/feature-gate.rs:51:12
+  --> $DIR/feature-gate.rs:61:12
    |
 LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -130,7 +273,7 @@ LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
 error[E0658]: `if let` guards are experimental
-  --> $DIR/feature-gate.rs:76:12
+  --> $DIR/feature-gate.rs:88:12
    |
 LL |         () if let 0 = 1 => {}
    |            ^^^^^^^^^^^^
@@ -149,7 +292,7 @@ LL |         () if (let 0 = 1) => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:14:18
+  --> $DIR/feature-gate.rs:15:18
    |
 LL |         () if (((let 0 = 1))) => {}
    |                  ^^^^^^^^^
@@ -158,7 +301,7 @@ LL |         () if (((let 0 = 1))) => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:18:23
+  --> $DIR/feature-gate.rs:20:23
    |
 LL |         () if true && let 0 = 1 => {}
    |                       ^^^^^^^^^
@@ -167,7 +310,7 @@ LL |         () if true && let 0 = 1 => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:22:15
+  --> $DIR/feature-gate.rs:24:15
    |
 LL |         () if let 0 = 1 && true => {}
    |               ^^^^^^^^^
@@ -176,7 +319,7 @@ LL |         () if let 0 = 1 && true => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:26:16
+  --> $DIR/feature-gate.rs:28:16
    |
 LL |         () if (let 0 = 1) && true => {}
    |                ^^^^^^^^^
@@ -185,7 +328,7 @@ LL |         () if (let 0 = 1) && true => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:30:24
+  --> $DIR/feature-gate.rs:33:24
    |
 LL |         () if true && (let 0 = 1) => {}
    |                        ^^^^^^^^^
@@ -194,7 +337,7 @@ LL |         () if true && (let 0 = 1) => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:34:16
+  --> $DIR/feature-gate.rs:38:16
    |
 LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    |                ^^^^^^^^^
@@ -203,7 +346,7 @@ LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:34:31
+  --> $DIR/feature-gate.rs:38:31
    |
 LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    |                               ^^^^^^^^^
@@ -212,7 +355,7 @@ LL |         () if (let 0 = 1) && (let 0 = 1) => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:40:15
+  --> $DIR/feature-gate.rs:46:15
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |               ^^^^^^^^^
@@ -221,7 +364,7 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:40:28
+  --> $DIR/feature-gate.rs:46:28
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                            ^^^^^^^^^
@@ -230,7 +373,7 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:40:42
+  --> $DIR/feature-gate.rs:46:42
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                                          ^^^^^^^^^
@@ -239,7 +382,7 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:40:55
+  --> $DIR/feature-gate.rs:46:55
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                                                       ^^^^^^^^^
@@ -248,7 +391,7 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:40:68
+  --> $DIR/feature-gate.rs:46:68
    |
 LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 = 5) => {}
    |                                                                    ^^^^^^^^^
@@ -257,7 +400,7 @@ LL |         () if let 0 = 1 && let 1 = 2 && (let 2 = 3 && let 3 = 4 && let 4 =
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:51:15
+  --> $DIR/feature-gate.rs:61:15
    |
 LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -266,7 +409,7 @@ LL |         () if let Range { start: _, end: _ } = (true..true) && false => {}
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:68:16
+  --> $DIR/feature-gate.rs:78:16
    |
 LL |     use_expr!((let 0 = 1 && 0 == 0));
    |                ^^^^^^^^^
@@ -275,7 +418,7 @@ LL |     use_expr!((let 0 = 1 && 0 == 0));
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
 error[E0658]: `let` expressions in this position are unstable
-  --> $DIR/feature-gate.rs:71:16
+  --> $DIR/feature-gate.rs:82:16
    |
 LL |     use_expr!((let 0 = 1));
    |                ^^^^^^^^^
@@ -283,6 +426,6 @@ LL |     use_expr!((let 0 = 1));
    = note: see issue #53667 <https://github.com/rust-lang/rust/issues/53667> for more information
    = help: add `#![feature(let_chains)]` to the crate attributes to enable
 
-error: aborting due to 34 previous errors
+error: aborting due to 45 previous errors
 
 For more information about this error, try `rustc --explain E0658`.

tests/ui/rfc-2497-if-let-chains/ast-validate-guards.rs

@@ -0,0 +1,23 @@
+#![feature(let_chains)]
+
+fn let_or_guard(x: Result<Option<i32>, ()>) {
+    match x {
+        Ok(opt) if let Some(4) = opt || false  => {}
+        //~^ ERROR `let` expressions are not supported here
+        _ => {}
+    }
+}
+
+fn hiding_unsafe_mod(x: Result<Option<i32>, ()>) {
+    match x {
+        Ok(opt)
+            if {
+                unsafe mod a {};
+                //~^ ERROR module cannot be declared unsafe
+                false
+            } => {}
+        _ => {}
+    }
+}
+
+fn main() {}

tests/ui/rfc-2497-if-let-chains/ast-validate-guards.stderr

@@ -0,0 +1,21 @@
+error: `let` expressions are not supported here
+  --> $DIR/ast-validate-guards.rs:5:20
+   |
+LL |         Ok(opt) if let Some(4) = opt || false  => {}
+   |                    ^^^^^^^^^^^^^^^^^
+   |
+   = note: only supported directly in conditions of `if` and `while` expressions
+note: `||` operators are not supported in let chain expressions
+  --> $DIR/ast-validate-guards.rs:5:38
+   |
+LL |         Ok(opt) if let Some(4) = opt || false  => {}
+   |                                      ^^
+
+error: module cannot be declared unsafe
+  --> $DIR/ast-validate-guards.rs:15:17
+   |
+LL |                 unsafe mod a {};
+   |                 ^^^^^^
+
+error: aborting due to 2 previous errors
+