stop evaluating constants in Relate

compiler/rustc_middle/src/ty/relate.rs

@@ -594,10 +594,6 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
         );
     }
 
-    let eagerly_eval = |x: ty::Const<'tcx>| x.eval(tcx, relation.param_env());
-    let a = eagerly_eval(a);
-    let b = eagerly_eval(b);
-
     // Currently, the values that can be unified are primitive types,
     // and those that derive both `PartialEq` and `Eq`, corresponding
     // to structural-match types.

compiler/rustc_trait_selection/src/traits/project.rs

@@ -635,7 +635,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
 
     #[instrument(skip(self), level = "debug")]
     fn fold_const(&mut self, constant: ty::Const<'tcx>) -> ty::Const<'tcx> {
-        if self.selcx.tcx().lazy_normalization() || !self.eager_inference_replacement {
+        if self.selcx.tcx().lazy_normalization() {
             constant
         } else {
             let constant = constant.super_fold_with(self);

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -495,13 +495,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     pub fn to_const(&self, ast_c: &hir::AnonConst) -> ty::Const<'tcx> {
         let const_def_id = self.tcx.hir().local_def_id(ast_c.hir_id);
+        let span = self.tcx.hir().span(ast_c.hir_id);
         let c = ty::Const::from_anon_const(self.tcx, const_def_id);
-        self.register_wf_obligation(
-            c.into(),
-            self.tcx.hir().span(ast_c.hir_id),
-            ObligationCauseCode::WellFormed(None),
-        );
-        c
+        self.register_wf_obligation(c.into(), span, ObligationCauseCode::WellFormed(None));
+        self.normalize_associated_types_in(span, c)
     }
 
     pub fn const_arg_to_const(

src/test/ui/closures/issue-52437.rs

@@ -2,5 +2,4 @@ fn main() {
     [(); &(&'static: loop { |x| {}; }) as *const _ as usize]
     //~^ ERROR: invalid label name `'static`
     //~| ERROR: type annotations needed
-    //~| ERROR mismatched types
 }

src/test/ui/closures/issue-52437.stderr

@@ -15,15 +15,6 @@ help: consider giving this closure parameter an explicit type
 LL |     [(); &(&'static: loop { |x: _| {}; }) as *const _ as usize]
    |                               +++
 
-error[E0308]: mismatched types
-  --> $DIR/issue-52437.rs:2:5
-   |
-LL | fn main() {
-   |           - expected `()` because of default return type
-LL |     [(); &(&'static: loop { |x| {}; }) as *const _ as usize]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[(); _]`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0282, E0308.
-For more information about an error, try `rustc --explain E0282`.
+For more information about this error, try `rustc --explain E0282`.

src/test/ui/issues/issue-66706.rs

@@ -2,7 +2,6 @@ fn a() {
     [0; [|_: _ &_| ()].len()]
     //~^ ERROR expected `,`, found `&`
     //~| ERROR type annotations needed
-    //~| ERROR mismatched types
 }
 
 fn b() {
@@ -13,13 +12,11 @@ fn b() {
 fn c() {
     [0; [|&_: _ &_| {}; 0 ].len()]
     //~^ ERROR expected `,`, found `&`
-    //~| ERROR mismatched types
 }
 
 fn d() {
     [0; match [|f @ &ref _| () ] {} ]
     //~^ ERROR expected identifier, found reserved identifier `_`
-    //~| ERROR mismatched types
 }
 
 fn main() {}

src/test/ui/issues/issue-66706.stderr

@@ -7,21 +7,21 @@ LL |     [0; [|_: _ &_| ()].len()]
    |               help: missing `,`
 
 error: expected identifier, found reserved identifier `_`
-  --> $DIR/issue-66706.rs:9:20
+  --> $DIR/issue-66706.rs:8:20
    |
 LL |     [0; [|f @ &ref _| {} ; 0 ].len() ];
    |                    ^ expected identifier, found reserved identifier
 
 error: expected `,`, found `&`
-  --> $DIR/issue-66706.rs:14:17
+  --> $DIR/issue-66706.rs:13:17
    |
 LL |     [0; [|&_: _ &_| {}; 0 ].len()]
    |                -^ expected `,`
    |                |
    |                help: missing `,`
 
 error: expected identifier, found reserved identifier `_`
-  --> $DIR/issue-66706.rs:20:26
+  --> $DIR/issue-66706.rs:18:26
    |
 LL |     [0; match [|f @ &ref _| () ] {} ]
    |                          ^ expected identifier, found reserved identifier
@@ -32,31 +32,6 @@ error[E0282]: type annotations needed
 LL |     [0; [|_: _ &_| ()].len()]
    |           ^ cannot infer type
 
-error[E0308]: mismatched types
-  --> $DIR/issue-66706.rs:2:5
-   |
-LL | fn a() {
-   |        - help: try adding a return type: `-> [i32; _]`
-LL |     [0; [|_: _ &_| ()].len()]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
-
-error[E0308]: mismatched types
-  --> $DIR/issue-66706.rs:14:5
-   |
-LL | fn c() {
-   |        - help: try adding a return type: `-> [i32; _]`
-LL |     [0; [|&_: _ &_| {}; 0 ].len()]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
-
-error[E0308]: mismatched types
-  --> $DIR/issue-66706.rs:20:5
-   |
-LL | fn d() {
-   |        - help: try adding a return type: `-> [i32; _]`
-LL |     [0; match [|f @ &ref _| () ] {} ]
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found array `[{integer}; _]`
-
-error: aborting due to 8 previous errors
+error: aborting due to 5 previous errors
 
-Some errors have detailed explanations: E0282, E0308.
-For more information about an error, try `rustc --explain E0282`.
+For more information about this error, try `rustc --explain E0282`.