Fix for issue 91058

Author: compiler-errors

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -1695,11 +1695,23 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             }
             _ => exp_found,
         };
-        debug!("exp_found {:?} terr {:?}", exp_found, terr);
+        debug!("exp_found {:?} terr {:?} cause.code {:?}", exp_found, terr, cause.code);
         if let Some(exp_found) = exp_found {
-            self.suggest_as_ref_where_appropriate(span, &exp_found, diag);
-            self.suggest_accessing_field_where_appropriate(cause, &exp_found, diag);
-            self.suggest_await_on_expect_found(cause, span, &exp_found, diag);
+            let should_suggest_fixes = if let ObligationCauseCode::Pattern { root_ty, .. } =
+                &cause.code
+            {
+                // Skip if the root_ty of the pattern is not the same as the expected_ty.
+                // If these types aren't equal then we've probably peeled off a layer of arrays.
+                same_type_modulo_infer(self.resolve_vars_if_possible(*root_ty), exp_found.expected)
+            } else {
+                true
+            };
+
+            if should_suggest_fixes {
+                self.suggest_as_ref_where_appropriate(span, &exp_found, diag);
+                self.suggest_accessing_field_where_appropriate(cause, &exp_found, diag);
+                self.suggest_await_on_expect_found(cause, span, &exp_found, diag);
+            }
         }
 
         // In some (most?) cases cause.body_id points to actual body, but in some cases

src/test/ui/half-open-range-patterns/exclusive_range_pattern_syntax_collision.stderr

@@ -8,10 +8,6 @@ LL |         [_, 99.., _] => {},
    |
    = note: expected struct `std::ops::Range<{integer}>`
                 found type `{integer}`
-help: you might have meant to use field `start` whose type is `{integer}`
-   |
-LL |     match [5..4, 99..105, 43..44].start {
-   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 

src/test/ui/half-open-range-patterns/exclusive_range_pattern_syntax_collision2.stderr

@@ -14,10 +14,6 @@ LL |         [_, 99..] => {},
    |
    = note: expected struct `std::ops::Range<{integer}>`
                 found type `{integer}`
-help: you might have meant to use field `start` whose type is `{integer}`
-   |
-LL |     match [5..4, 99..105, 43..44].start {
-   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 

src/test/ui/half-open-range-patterns/exclusive_range_pattern_syntax_collision3.stderr

@@ -8,10 +8,6 @@ LL |         [..9, 99..100, _] => {},
    |
    = note: expected struct `std::ops::Range<{integer}>`
                 found type `{integer}`
-help: you might have meant to use field `start` whose type is `{integer}`
-   |
-LL |     match [5..4, 99..105, 43..44].start {
-   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/exclusive_range_pattern_syntax_collision3.rs:6:15
@@ -25,10 +21,6 @@ LL |         [..9, 99..100, _] => {},
    |
    = note: expected struct `std::ops::Range<{integer}>`
                 found type `{integer}`
-help: you might have meant to use field `start` whose type is `{integer}`
-   |
-LL |     match [5..4, 99..105, 43..44].start {
-   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0308]: mismatched types
   --> $DIR/exclusive_range_pattern_syntax_collision3.rs:6:19
@@ -42,10 +34,6 @@ LL |         [..9, 99..100, _] => {},
    |
    = note: expected struct `std::ops::Range<{integer}>`
                 found type `{integer}`
-help: you might have meant to use field `start` whose type is `{integer}`
-   |
-LL |     match [5..4, 99..105, 43..44].start {
-   |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 3 previous errors
 

src/test/ui/match/issue-91058.rs

@@ -0,0 +1,11 @@
+struct S(());
+
+fn main() {
+    let array = [S(())];
+
+    match array {
+        [()] => {}
+        //~^ ERROR mismatched types [E0308]
+        _ => {}
+    }
+}

src/test/ui/match/issue-91058.stderr

@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-91058.rs:7:10
+   |
+LL |     match array {
+   |           ----- this expression has type `[S; 1]`
+LL |         [()] => {}
+   |          ^^ expected struct `S`, found `()`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.