check_expr_struct_fields: taint context with errors if struct definition is malformed

Author: olafes

compiler/rustc_hir_typeck/src/expr.rs

@@ -1672,7 +1672,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let mut seen_fields = FxHashMap::default();
 
-        let mut error_happened = false;
+        let mut error_happened = if variant.fields.len() > remaining_fields.len() {
+            // Some field is defined more than once. Make sure we don't try to
+            // instantiate this struct in static/const context.
+            let guar = self.dcx().span_delayed_bug(expr.span, "struct fields have non-unique names");
+            self.set_tainted_by_errors(guar);
+
+            true
+        } else {
+            false
+        };
+
 
         // Type-check each field.
         for (idx, field) in hir_fields.iter().enumerate() {

tests/ui/static/issue-125842.rs

@@ -0,0 +1,21 @@
+// Do not try to evaluate static initalizers that reference
+// ill-defined types. This used to be an ICE.
+// See issues #125842 and #124464.
+struct Struct {
+    field: Option<u8>,
+    field: u8,
+//~^ ERROR field `field` is already declared
+}
+
+static STATIC_A: Struct = Struct {
+    field: 1
+};
+
+static STATIC_B: Struct = {
+    let field = 1;
+    Struct {
+        field,
+    }
+};
+
+fn main() {}

tests/ui/static/issue-125842.stderr

@@ -0,0 +1,11 @@
+error[E0124]: field `field` is already declared
+  --> $DIR/issue-125842.rs:6:5
+   |
+LL |     field: Option<u8>,
+   |     ----------------- `field` first declared here
+LL |     field: u8,
+   |     ^^^^^^^^^ field already declared
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0124`.