Rollup merge of #116073 - compiler-errors:poly-sigs, r=b-naber

matthiaskrgr · web-flow · commit d92a1bd7ccc4 · 2023-09-24T01:14:05.000+02:00
Allow higher-ranked fn sigs in `ValuePairs` For better bookkeeping -- only affects diagnostic path. Allow reporting signature mismatches like "signature"s and not "fn pointer"s. Improves #115897 (comment)
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -1134,7 +1134,10 @@ fn report_trait_method_mismatch<'tcx>(
         &mut diag,
         &cause,
         trait_err_span.map(|sp| (sp, Cow::from("type in trait"))),
-        Some(infer::ValuePairs::Sigs(ExpectedFound { expected: trait_sig, found: impl_sig })),
+        Some(infer::ValuePairs::PolySigs(ExpectedFound {
+            expected: ty::Binder::dummy(trait_sig),
+            found: ty::Binder::dummy(impl_sig),
+        })),
         terr,
         false,
         false,
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -573,10 +573,7 @@ pub fn check_function_signature<'tcx>(
     let norm_cause = ObligationCause::misc(cause.span, local_id);
     let actual_sig = ocx.normalize(&norm_cause, param_env, actual_sig);
 
-    let expected_ty = Ty::new_fn_ptr(tcx, expected_sig);
-    let actual_ty = Ty::new_fn_ptr(tcx, actual_sig);
-
-    match ocx.eq(&cause, param_env, expected_ty, actual_ty) {
+    match ocx.eq(&cause, param_env, expected_sig, actual_sig) {
         Ok(()) => {
             let errors = ocx.select_all_or_error();
             if !errors.is_empty() {
@@ -595,9 +592,9 @@ pub fn check_function_signature<'tcx>(
                 &mut diag,
                 &cause,
                 None,
-                Some(infer::ValuePairs::Sigs(ExpectedFound {
-                    expected: tcx.liberate_late_bound_regions(fn_id, expected_sig),
-                    found: tcx.liberate_late_bound_regions(fn_id, actual_sig),
+                Some(infer::ValuePairs::PolySigs(ExpectedFound {
+                    expected: expected_sig,
+                    found: actual_sig,
                 })),
                 err,
                 false,
diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs
@@ -478,7 +478,28 @@ impl<'tcx> ToTrace<'tcx> for ty::FnSig<'tcx> {
         a: Self,
         b: Self,
     ) -> TypeTrace<'tcx> {
-        TypeTrace { cause: cause.clone(), values: Sigs(ExpectedFound::new(a_is_expected, a, b)) }
+        TypeTrace {
+            cause: cause.clone(),
+            values: PolySigs(ExpectedFound::new(
+                a_is_expected,
+                ty::Binder::dummy(a),
+                ty::Binder::dummy(b),
+            )),
+        }
+    }
+}
+
+impl<'tcx> ToTrace<'tcx> for ty::PolyFnSig<'tcx> {
+    fn to_trace(
+        cause: &ObligationCause<'tcx>,
+        a_is_expected: bool,
+        a: Self,
+        b: Self,
+    ) -> TypeTrace<'tcx> {
+        TypeTrace {
+            cause: cause.clone(),
+            values: PolySigs(ExpectedFound::new(a_is_expected, a, b)),
+        }
     }
 }
 
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -1660,7 +1660,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                             _ => (false, Mismatch::Fixed("type")),
                         }
                     }
-                    ValuePairs::Sigs(infer::ExpectedFound { expected, found }) => {
+                    ValuePairs::PolySigs(infer::ExpectedFound { expected, found }) => {
                         OpaqueTypesVisitor::visit_expected_found(self.tcx, expected, found, span)
                             .report(diag);
                         (false, Mismatch::Fixed("signature"))
@@ -2232,15 +2232,12 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     ret => ret,
                 }
             }
-            infer::Sigs(exp_found) => {
+            infer::PolySigs(exp_found) => {
                 let exp_found = self.resolve_vars_if_possible(exp_found);
                 if exp_found.references_error() {
                     return None;
                 }
-                let (exp, fnd) = self.cmp_fn_sig(
-                    &ty::Binder::dummy(exp_found.expected),
-                    &ty::Binder::dummy(exp_found.found),
-                );
+                let (exp, fnd) = self.cmp_fn_sig(&exp_found.expected, &exp_found.found);
                 Some((exp, fnd, None, None))
             }
         }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/trait_impl_difference.rs
@@ -35,14 +35,14 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             && let (Subtype(sup_trace), Subtype(sub_trace)) = (&sup_origin, &sub_origin)
             && let CompareImplItemObligation { trait_item_def_id, .. } = sub_trace.cause.code()
             && sub_trace.values == sup_trace.values
-            && let ValuePairs::Sigs(ExpectedFound { expected, found }) = sub_trace.values
+            && let ValuePairs::PolySigs(ExpectedFound { expected, found }) = sub_trace.values
         {
             // FIXME(compiler-errors): Don't like that this needs `Ty`s, but
             // all of the region highlighting machinery only deals with those.
             let guar = self.emit_err(
                 var_origin.span(),
-                Ty::new_fn_ptr(self.cx.tcx,ty::Binder::dummy(expected)),
-                Ty::new_fn_ptr(self.cx.tcx,ty::Binder::dummy(found)),
+                Ty::new_fn_ptr(self.cx.tcx, expected),
+                Ty::new_fn_ptr(self.cx.tcx, found),
                 *trait_item_def_id,
             );
             return Some(guar);
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
@@ -383,7 +383,7 @@ pub enum ValuePairs<'tcx> {
     Aliases(ExpectedFound<ty::AliasTy<'tcx>>),
     TraitRefs(ExpectedFound<ty::TraitRef<'tcx>>),
     PolyTraitRefs(ExpectedFound<ty::PolyTraitRef<'tcx>>),
-    Sigs(ExpectedFound<ty::FnSig<'tcx>>),
+    PolySigs(ExpectedFound<ty::PolyFnSig<'tcx>>),
     ExistentialTraitRef(ExpectedFound<ty::PolyExistentialTraitRef<'tcx>>),
     ExistentialProjection(ExpectedFound<ty::PolyExistentialProjection<'tcx>>),
 }
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
@@ -2333,7 +2333,10 @@ impl CheckAttrVisitor<'_> {
                 &mut diag,
                 &cause,
                 None,
-                Some(ValuePairs::Sigs(ExpectedFound { expected: expected_sig, found: sig })),
+                Some(ValuePairs::PolySigs(ExpectedFound {
+                    expected: ty::Binder::dummy(expected_sig),
+                    found: ty::Binder::dummy(sig),
+                })),
                 terr,
                 false,
                 false,
diff --git a/tests/ui/panic-handler/panic-handler-bad-signature-1.stderr b/tests/ui/panic-handler/panic-handler-bad-signature-1.stderr
@@ -4,8 +4,8 @@ error[E0308]: `#[panic_handler]` function has wrong type
 LL | fn panic(info: PanicInfo) -> () {}
    |                ^^^^^^^^^ expected `&PanicInfo<'_>`, found `PanicInfo<'_>`
    |
-   = note: expected signature `fn(&PanicInfo<'_>) -> !`
-              found signature `fn(PanicInfo<'_>)`
+   = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> !`
+              found signature `for<'a> fn(PanicInfo<'a>)`
 
 error: aborting due to previous error
 
diff --git a/tests/ui/panic-handler/panic-handler-bad-signature-2.stderr b/tests/ui/panic-handler/panic-handler-bad-signature-2.stderr
@@ -4,8 +4,8 @@ error[E0308]: `#[panic_handler]` function has wrong type
 LL | fn panic(info: &'static PanicInfo) -> !
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
-              found fn pointer `for<'a> fn(&'static PanicInfo<'a>) -> _`
+   = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
+              found signature `for<'a> fn(&'static PanicInfo<'a>) -> _`
 
 error: aborting due to previous error
 
diff --git a/tests/ui/panic-handler/panic-handler-bad-signature-3.stderr b/tests/ui/panic-handler/panic-handler-bad-signature-3.stderr
@@ -4,7 +4,7 @@ error[E0308]: `#[panic_handler]` function has wrong type
 LL | fn panic() -> ! {
    | ^^^^^^^^^^^^^^^ incorrect number of function parameters
    |
-   = note: expected signature `fn(&PanicInfo<'_>) -> _`
+   = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
               found signature `fn() -> _`
 
 error: aborting due to previous error
diff --git a/tests/ui/panic-handler/panic-handler-bad-signature-5.stderr b/tests/ui/panic-handler/panic-handler-bad-signature-5.stderr
@@ -4,8 +4,8 @@ error[E0308]: `#[panic_handler]` function has wrong type
 LL | fn panic(info: &PanicInfo<'static>) -> !
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected fn pointer `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
-              found fn pointer `for<'a> fn(&'a PanicInfo<'static>) -> _`
+   = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
+              found signature `for<'a> fn(&'a PanicInfo<'static>) -> _`
 
 error: aborting due to previous error
 

Original file line number	Diff line number	Diff line change
`@@ -1660,7 +1660,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {`
`1660`	`1660`	`_ => (false, Mismatch::Fixed("type")),`
`1661`	`1661`	`}`
`1662`	`1662`	`}`
`1663`		`- ValuePairs::Sigs(infer::ExpectedFound { expected, found }) => {`
	`1663`	`+ ValuePairs::PolySigs(infer::ExpectedFound { expected, found }) => {`
`1664`	`1664`	`OpaqueTypesVisitor::visit_expected_found(self.tcx, expected, found, span)`
`1665`	`1665`	`.report(diag);`
`1666`	`1666`	`(false, Mismatch::Fixed("signature"))`
`@@ -2232,15 +2232,12 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {`
`2232`	`2232`	`ret => ret,`
`2233`	`2233`	`}`
`2234`	`2234`	`}`
`2235`		`- infer::Sigs(exp_found) => {`
	`2235`	`+ infer::PolySigs(exp_found) => {`
`2236`	`2236`	`let exp_found = self.resolve_vars_if_possible(exp_found);`
`2237`	`2237`	`if exp_found.references_error() {`
`2238`	`2238`	`return None;`
`2239`	`2239`	`}`
`2240`		`- let (exp, fnd) = self.cmp_fn_sig(`
`2241`		`- &ty::Binder::dummy(exp_found.expected),`
`2242`		`- &ty::Binder::dummy(exp_found.found),`
`2243`		`- );`
	`2240`	`+ let (exp, fnd) = self.cmp_fn_sig(&exp_found.expected, &exp_found.found);`
`2244`	`2241`	`Some((exp, fnd, None, None))`
`2245`	`2242`	`}`
`2246`	`2243`	`}`
Original file line number	Diff line number	Diff line change
`@@ -383,7 +383,7 @@ pub enum ValuePairs<'tcx> {`
`383`	`383`	`Aliases(ExpectedFound<ty::AliasTy<'tcx>>),`
`384`	`384`	`TraitRefs(ExpectedFound<ty::TraitRef<'tcx>>),`
`385`	`385`	`PolyTraitRefs(ExpectedFound<ty::PolyTraitRef<'tcx>>),`
`386`		`- Sigs(ExpectedFound<ty::FnSig<'tcx>>),`
	`386`	`+ PolySigs(ExpectedFound<ty::PolyFnSig<'tcx>>),`
`387`	`387`	`ExistentialTraitRef(ExpectedFound<ty::PolyExistentialTraitRef<'tcx>>),`
`388`	`388`	`ExistentialProjection(ExpectedFound<ty::PolyExistentialProjection<'tcx>>),`
`389`	`389`	`}`
Original file line number	Diff line number	Diff line change
@@ -4,8 +4,8 @@ error[E0308]: `#[panic_handler]` function has wrong type
`4`	`4`	`LL \| fn panic(info: PanicInfo) -> () {}`
`5`	`5`	\| ^^^^^^^^^ expected `&PanicInfo<'_>`, found `PanicInfo<'_>`
`6`	`6`	`\|`
`7`		- = note: expected signature `fn(&PanicInfo<'_>) -> !`
`8`		- found signature `fn(PanicInfo<'_>)`
	`7`	+ = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> !`
	`8`	+ found signature `for<'a> fn(PanicInfo<'a>)`
`9`	`9`
`10`	`10`	`error: aborting due to previous error`
`11`	`11`
Original file line number	Diff line number	Diff line change
@@ -4,8 +4,8 @@ error[E0308]: `#[panic_handler]` function has wrong type
`4`	`4`	`LL \| fn panic(info: &'static PanicInfo) -> !`
`5`	`5`	`\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other`
`6`	`6`	`\|`
`7`		- = note: expected fn pointer `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
`8`		- found fn pointer `for<'a> fn(&'static PanicInfo<'a>) -> _`
	`7`	+ = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
	`8`	+ found signature `for<'a> fn(&'static PanicInfo<'a>) -> _`
`9`	`9`
`10`	`10`	`error: aborting due to previous error`
`11`	`11`
Original file line number	Diff line number	Diff line change
@@ -4,7 +4,7 @@ error[E0308]: `#[panic_handler]` function has wrong type
`4`	`4`	`LL \| fn panic() -> ! {`
`5`	`5`	`\| ^^^^^^^^^^^^^^^ incorrect number of function parameters`
`6`	`6`	`\|`
`7`		- = note: expected signature `fn(&PanicInfo<'_>) -> _`
	`7`	+ = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
`8`	`8`	found signature `fn() -> _`
`9`	`9`
`10`	`10`	`error: aborting due to previous error`
Original file line number	Diff line number	Diff line change
@@ -4,8 +4,8 @@ error[E0308]: `#[panic_handler]` function has wrong type
`4`	`4`	`LL \| fn panic(info: &PanicInfo<'static>) -> !`
`5`	`5`	`\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one type is more general than the other`
`6`	`6`	`\|`
`7`		- = note: expected fn pointer `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
`8`		- found fn pointer `for<'a> fn(&'a PanicInfo<'static>) -> _`
	`7`	+ = note: expected signature `for<'a, 'b> fn(&'a PanicInfo<'b>) -> _`
	`8`	+ found signature `for<'a> fn(&'a PanicInfo<'static>) -> _`
`9`	`9`
`10`	`10`	`error: aborting due to previous error`
`11`	`11`