Rollup merge of rust-lang#85800 - BoxyUwU:const-param-default-diagnos…

…tics, r=oli-obk Fix some diagnostic issues with const_generics_defaults feature gate This PR makes a few changes: - print out const param defaults in "lifetime ordering" errors rather than discarding them - update `is_simple_text` to account for const params when checking if a type has no generics, this was causing a note to be failed to add to an error message - fixes some diagnostic wording that incorrectly said there was ordering restrictions between type/const params despite the `const_generics_defaults` feature gate is active
Dylan-DPC-zz · Jun 11, 2021 · 1e8c685 · 1e8c685
2 parents 66ba810 + 47fe696
commit 1e8c685
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Showing 8 changed files with 47 additions and 16 deletions.
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -938,8 +938,11 @@ fn validate_generic_param_order(
  }
  GenericParamKind::Type { default: None } => (),
  GenericParamKind::Lifetime => (),
- // FIXME(const_generics_defaults)
- GenericParamKind::Const { ty: _, kw_span: _, default: _ } => (),
+ GenericParamKind::Const { ty: _, kw_span: _, default: Some(default) } => {
+ ordered_params += " = ";
+ ordered_params += &pprust::expr_to_string(&*default.value);
+ }
+ GenericParamKind::Const { ty: _, kw_span: _, default: None } => (),
  }
  first = false;
  }
@@ -959,7 +962,7 @@ fn validate_generic_param_order(
  span,
  &format!(
  "reorder the parameters: lifetimes, {}",
- if sess.features_untracked().const_generics {
+ if sess.features_untracked().unordered_const_ty_params() {
  "then consts and types"
  } else {
  "then types, then consts"

diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs
@@ -54,7 +54,7 @@ impl<'tcx> TyS<'tcx> {
  /// ADTs with no type arguments.
  pub fn is_simple_text(&self) -> bool {
  match self.kind() {
- Adt(_, substs) => substs.types().next().is_none(),
+ Adt(_, substs) => substs.non_erasable_generics().next().is_none(),
  Ref(_, ty, _) => ty.is_simple_text(),
  _ => self.is_simple_ty(),
  }

diff --git a/src/test/ui/const-generics/defaults/intermixed-lifetime.min.stderr b/src/test/ui/const-generics/defaults/intermixed-lifetime.min.stderr
@@ -2,13 +2,13 @@ error: lifetime parameters must be declared prior to const parameters
  --> $DIR/intermixed-lifetime.rs:7:28
  |
 LL | struct Foo<const N: usize, 'a, T = u32>(&'a (), T);
- | -----------------^^---------- help: reorder the parameters: lifetimes, then types, then consts: `<'a, const N: usize, T = u32>`
+ | -----------------^^---------- help: reorder the parameters: lifetimes, then consts and types: `<'a, const N: usize, T = u32>`
 
 error: lifetime parameters must be declared prior to type parameters
  --> $DIR/intermixed-lifetime.rs:10:37
  |
 LL | struct Bar<const N: usize, T = u32, 'a>(&'a (), T);
- | --------------------------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, const N: usize, T = u32>`
+ | --------------------------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, const N: usize, T = u32>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/const-generics/defaults/mismatch.full.stderr b/src/test/ui/const-generics/defaults/mismatch.full.stderr
@@ -5,9 +5,12 @@ LL | let e: Example::<13> = ();
  | ------------- ^^ expected struct `Example`, found `()`
  | |
  | expected due to this
+ |
+ = note: expected struct `Example`
+ found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:14:34
+ --> $DIR/mismatch.rs:15:34
  |
 LL | let e: Example2::<u32, 13> = ();
  | ------------------- ^^ expected struct `Example2`, found `()`
@@ -18,7 +21,7 @@ LL | let e: Example2::<u32, 13> = ();
  found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:16:34
+ --> $DIR/mismatch.rs:18:34
  |
 LL | let e: Example3::<13, u32> = ();
  | ------------------- ^^ expected struct `Example3`, found `()`
@@ -29,7 +32,7 @@ LL | let e: Example3::<13, u32> = ();
  found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:18:28
+ --> $DIR/mismatch.rs:21:28
  |
 LL | let e: Example3::<7> = ();
  | ------------- ^^ expected struct `Example3`, found `()`
@@ -40,12 +43,15 @@ LL | let e: Example3::<7> = ();
  found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:22:28
+ --> $DIR/mismatch.rs:24:28
  |
 LL | let e: Example4::<7> = ();
  | ------------- ^^ expected struct `Example4`, found `()`
  | |
  | expected due to this
+ |
+ = note: expected struct `Example4<7_usize>`
+ found unit type `()`
 
 error: aborting due to 5 previous errors
 

diff --git a/src/test/ui/const-generics/defaults/mismatch.min.stderr b/src/test/ui/const-generics/defaults/mismatch.min.stderr
@@ -5,9 +5,12 @@ LL | let e: Example::<13> = ();
  | ------------- ^^ expected struct `Example`, found `()`
  | |
  | expected due to this
+ |
+ = note: expected struct `Example`
+ found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:14:34
+ --> $DIR/mismatch.rs:15:34
  |
 LL | let e: Example2::<u32, 13> = ();
  | ------------------- ^^ expected struct `Example2`, found `()`
@@ -18,7 +21,7 @@ LL | let e: Example2::<u32, 13> = ();
  found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:16:34
+ --> $DIR/mismatch.rs:18:34
  |
 LL | let e: Example3::<13, u32> = ();
  | ------------------- ^^ expected struct `Example3`, found `()`
@@ -29,7 +32,7 @@ LL | let e: Example3::<13, u32> = ();
  found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:18:28
+ --> $DIR/mismatch.rs:21:28
  |
 LL | let e: Example3::<7> = ();
  | ------------- ^^ expected struct `Example3`, found `()`
@@ -40,12 +43,15 @@ LL | let e: Example3::<7> = ();
  found unit type `()`
 
 error[E0308]: mismatched types
- --> $DIR/mismatch.rs:22:28
+ --> $DIR/mismatch.rs:24:28
  |
 LL | let e: Example4::<7> = ();
  | ------------- ^^ expected struct `Example4`, found `()`
  | |
  | expected due to this
+ |
+ = note: expected struct `Example4<7_usize>`
+ found unit type `()`
 
 error: aborting due to 5 previous errors
 

diff --git a/src/test/ui/const-generics/defaults/mismatch.rs b/src/test/ui/const-generics/defaults/mismatch.rs
@@ -11,14 +11,17 @@ pub struct Example4<const N: usize=13, const M: usize=4>;
 fn main() {
  let e: Example::<13> = ();
  //~^ Error: mismatched types
+ //~| expected struct `Example`
  let e: Example2::<u32, 13> = ();
  //~^ Error: mismatched types
+ //~| expected struct `Example2`
  let e: Example3::<13, u32> = ();
  //~^ Error: mismatched types
+ //~| expected struct `Example3`
  let e: Example3::<7> = ();
  //~^ Error: mismatched types
- // FIXME(const_generics_defaults): There should be a note for the error below, but it is
- // missing.
+ //~| expected struct `Example3<7_usize>`
  let e: Example4::<7> = ();
  //~^ Error: mismatched types
+ //~| expected struct `Example4<7_usize>`
 }
diff --git a/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs b/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.rs
@@ -0,0 +1,5 @@
+#![feature(const_generics_defaults)]
+struct Foo<const M: usize = 10, 'a>(&'a u32);
+//~^ Error lifetime parameters must be declared prior to const parameters
+
+fn main() {}
diff --git a/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr b/src/test/ui/const-generics/defaults/param-order-err-pretty-prints-default.stderr
@@ -0,0 +1,8 @@
+error: lifetime parameters must be declared prior to const parameters
+ --> $DIR/param-order-err-pretty-prints-default.rs:2:33
+ |
+LL | struct Foo<const M: usize = 10, 'a>(&'a u32);
+ | ----------------------^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, const M: usize = 10>`
+
+error: aborting due to previous error
+