Rollup merge of #134314 - compiler-errors:default-struct-value-const, r=estebank

Make sure to use normalized ty for unevaluated const in default struct value

This cleans up the way that we construct the `mir::Const::Unevaluated` for default struct values. We were previously using `from_unevaluated`, which doesn't normalize the type, and is really only used for inline assembly. Other codepaths (such as `ExprKind::NamedConst`) use the type from the body.

Also, let's stop using `literal_operand`, which also is really not meant for calls other than for literal comparisons in pattern lowering.

Also move all of the tests to a separate subdirectory so they don't need to have the same prefix on all the test files.

Fixes #134298
r? estebank or reassign

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

@@ -367,14 +367,20 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             .collect()
                     }
                     AdtExprBase::DefaultFields(field_types) => {
-                        itertools::zip_eq(field_names, &**field_types)
+                        itertools::zip_eq(field_names, field_types)
-                            .map(|(n, ty)| match fields_map.get(&n) {
+                            .map(|(n, &ty)| match fields_map.get(&n) {
                                 Some(v) => v.clone(),
                                 None => match variant.fields[n].value {
                                     Some(def) => {
-                                        let value = Const::from_unevaluated(this.tcx, def)
+                                        let value = Const::Unevaluated(
-                                            .instantiate(this.tcx, args);
+                                            UnevaluatedConst::new(def, args),
-                                        this.literal_operand(expr_span, value)
+                                            ty,
+                                        );
+                                        Operand::Constant(Box::new(ConstOperand {
+                                            span: expr_span,
+                                            user_ty: None,
+                                            const_: value,
+                                        }))
                                     }
                                     None => {
                                         let name = variant.fields[n].name;

tests/ui/structs/default-field-values/failures.stderr

@@ -1,5 +1,5 @@
 error: the `#[default]` attribute may only be used on unit enum variants or variants where every field has a default value
-  --> $DIR/default-field-values-failures.rs:47:5
+  --> $DIR/failures.rs:47:5
    |
 LL |     Variant {}
    |     ^^^^^^^
@@ -7,7 +7,7 @@ LL |     Variant {}
    = help: consider a manual implementation of `Default`
 
 error: generic parameters may not be used in const operations
-  --> $DIR/default-field-values-failures.rs:22:23
+  --> $DIR/failures.rs:22:23
    |
 LL |     bat: i32 = <Qux<{ C }> as T>::K,
    |                       ^ cannot perform const operation using `C`
@@ -16,19 +16,19 @@ LL |     bat: i32 = <Qux<{ C }> as T>::K,
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: default fields are not supported in tuple structs
-  --> $DIR/default-field-values-failures.rs:26:22
+  --> $DIR/failures.rs:26:22
    |
 LL | pub struct Rak(i32 = 42);
    |                      ^^ default fields are only supported on structs
 
 error: generic `Self` types are currently not permitted in anonymous constants
-  --> $DIR/default-field-values-failures.rs:20:14
+  --> $DIR/failures.rs:20:14
    |
 LL |     bar: S = Self::S,
    |              ^^^^
 
 error[E0277]: the trait bound `S: Default` is not satisfied
-  --> $DIR/default-field-values-failures.rs:14:5
+  --> $DIR/failures.rs:14:5
    |
 LL | #[derive(Debug, Default)]
    |                 ------- in this derive macro expansion
@@ -44,13 +44,13 @@ LL | pub struct S;
    |
 
 error: missing mandatory field `bar`
-  --> $DIR/default-field-values-failures.rs:53:21
+  --> $DIR/failures.rs:53:21
    |
 LL |     let _ = Bar { .. };
    |                     ^
 
 error[E0308]: mismatched types
-  --> $DIR/default-field-values-failures.rs:57:17
+  --> $DIR/failures.rs:57:17
    |
 LL |     let _ = Rak(..);
    |             --- ^^ expected `i32`, found `RangeFull`
@@ -58,29 +58,29 @@ LL |     let _ = Rak(..);
    |             arguments to this struct are incorrect
    |
 note: tuple struct defined here
-  --> $DIR/default-field-values-failures.rs:26:12
+  --> $DIR/failures.rs:26:12
    |
 LL | pub struct Rak(i32 = 42);
    |            ^^^
 help: you might have meant to use `..` to skip providing a value for expected fields, but this is only supported on non-tuple struct literals; it is instead interpreted as a `std::ops::RangeFull` literal
-  --> $DIR/default-field-values-failures.rs:57:17
+  --> $DIR/failures.rs:57:17
    |
 LL |     let _ = Rak(..);
    |                 ^^
 
 error[E0061]: this struct takes 1 argument but 2 arguments were supplied
-  --> $DIR/default-field-values-failures.rs:59:13
+  --> $DIR/failures.rs:59:13
    |
 LL |     let _ = Rak(0, ..);
    |             ^^^    -- unexpected argument #2 of type `RangeFull`
    |
 help: you might have meant to use `..` to skip providing a value for expected fields, but this is only supported on non-tuple struct literals; it is instead interpreted as a `std::ops::RangeFull` literal
-  --> $DIR/default-field-values-failures.rs:59:20
+  --> $DIR/failures.rs:59:20
    |
 LL |     let _ = Rak(0, ..);
    |                    ^^
 note: tuple struct defined here
-  --> $DIR/default-field-values-failures.rs:26:12
+  --> $DIR/failures.rs:26:12
    |
 LL | pub struct Rak(i32 = 42);
    |            ^^^
@@ -91,18 +91,18 @@ LL +     let _ = Rak(0);
    |
 
 error[E0061]: this struct takes 1 argument but 2 arguments were supplied
-  --> $DIR/default-field-values-failures.rs:61:13
+  --> $DIR/failures.rs:61:13
    |
 LL |     let _ = Rak(.., 0);
    |             ^^^ -- unexpected argument #1 of type `RangeFull`
    |
 help: you might have meant to use `..` to skip providing a value for expected fields, but this is only supported on non-tuple struct literals; it is instead interpreted as a `std::ops::RangeFull` literal
-  --> $DIR/default-field-values-failures.rs:61:17
+  --> $DIR/failures.rs:61:17
    |
 LL |     let _ = Rak(.., 0);
    |                 ^^
 note: tuple struct defined here
-  --> $DIR/default-field-values-failures.rs:26:12
+  --> $DIR/failures.rs:26:12
    |
 LL | pub struct Rak(i32 = 42);
    |            ^^^

tests/ui/structs/default-field-values/invalid-const.stderr

@@ -1,13 +1,13 @@
 error[E0080]: evaluation of constant value failed
-  --> $DIR/default-field-values-invalid-const.rs:5:19
+  --> $DIR/invalid-const.rs:5:19
    |
 LL |     pub bax: u8 = panic!("asdf"),
-   |                   ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/default-field-values-invalid-const.rs:5:19
+   |                   ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/invalid-const.rs:5:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0080]: evaluation of `Baz::<C>::bat::{constant#0}` failed
-  --> $DIR/default-field-values-invalid-const.rs:11:19
+  --> $DIR/invalid-const.rs:11:19
    |
 LL |     pub bat: u8 = 130 + 130,
    |                   ^^^^^^^^^ attempt to compute `130_u8 + 130_u8`, which would overflow

tests/ui/structs/default-field-values/use-normalized-ty-for-default-struct-value.rs

@@ -0,0 +1,17 @@
+//@ check-pass
+
+#![feature(default_field_values)]
+
+struct Value<const VALUE: u8>;
+
+impl<const VALUE: u8> Value<VALUE> {
+    pub const VALUE: Self = Self;
+}
+
+pub struct WithUse {
+    _use: Value<{ 0 + 0 }> = Value::VALUE
+}
+
+const _: WithUse = WithUse { .. };
+
+fn main() {}