Rollup merge of #153453 - kpreid:fix-153388, r=fmease,estebank

Fix ICEs due to incomplete typechecking on struct literals with syntax errors.

Fixes #153388.
Followup to #153227.

Today I have learned that when we don’t emit a diagnostic *specifically from typeck*, we need to call `self.infcx.set_tainted_by_errors()` to signal that the type checking is incomplete despite the lack of error.

r? fmease

Author: JonathanBrouwer

compiler/rustc_hir_typeck/src/expr.rs

@@ -2203,14 +2203,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 };
                 self.typeck_results.borrow_mut().fru_field_types_mut().insert(expr.hir_id, fru_tys);
             }
-            rustc_hir::StructTailExpr::NoneWithError(ErrorGuaranteed { .. }) => {
+            rustc_hir::StructTailExpr::NoneWithError(guaranteed) => {
                 // If parsing the struct recovered from a syntax error, do not report missing
                 // fields. This prevents spurious errors when a field is intended to be present
                 // but a preceding syntax error caused it not to be parsed. For example, if a
                 // struct type `StructName` has fields `foo` and `bar`, then
                 //     StructName { foo(), bar: 2 }
                 // will not successfully parse a field `foo`, but we will not mention that,
                 // since the syntax error has already been reported.
+
+                // Signal that type checking has failed, even though we haven’t emitted a diagnostic
+                // about it ourselves.
+                self.infcx.set_tainted_by_errors(guaranteed);
             }
             rustc_hir::StructTailExpr::None => {
                 if adt_kind != AdtKind::Union

tests/ui/structs/syntax-error-not-missing-field.rs

@@ -47,4 +47,21 @@ fn enum_expr_missing_separator() {
     let e = Bar::Baz { a: make_a() b: 2 }; //~ ERROR found `b`
 }
 
+// Should error but not then ICE due to lack of type checking
+fn regression_test_for_issue_153388_a() {
+    struct TheStruct;
+    struct MyStruct {
+        value: i32,
+        s: TheStruct,
+    }
+    static A: MyStruct = MyStruct { ,s: TheStruct }; //~ ERROR expected identifier, found `,`
+}
+
+fn regression_test_for_issue_153388_b() {
+    struct MyStruct {
+        value: i32,
+    }
+    static A: MyStruct = MyStruct {,}; //~ ERROR expected identifier, found `,`
+}
+
 fn main() {}

tests/ui/structs/syntax-error-not-missing-field.stderr

@@ -89,5 +89,27 @@ LL |     let e = Bar::Baz { a: make_a() b: 2 };
    |             |                     help: try adding a comma: `,`
    |             while parsing this struct
 
-error: aborting due to 9 previous errors
+error: expected identifier, found `,`
+  --> $DIR/syntax-error-not-missing-field.rs:57:37
+   |
+LL |     static A: MyStruct = MyStruct { ,s: TheStruct };
+   |                          --------   ^ expected identifier
+   |                          |
+   |                          while parsing this struct
+   |
+help: remove this comma
+   |
+LL -     static A: MyStruct = MyStruct { ,s: TheStruct };
+LL +     static A: MyStruct = MyStruct { s: TheStruct };
+   |
+
+error: expected identifier, found `,`
+  --> $DIR/syntax-error-not-missing-field.rs:64:36
+   |
+LL |     static A: MyStruct = MyStruct {,};
+   |                          --------  ^ expected identifier
+   |                          |
+   |                          while parsing this struct
+
+error: aborting due to 11 previous errors