From dd57275c3e4d52b443090d0d75a9a3443bc5ce5c Mon Sep 17 00:00:00 2001
From: Bastian Kauschke <bastian_kauschke@hotmail.de>
Date: Mon, 14 Sep 2020 09:45:02 +0200
Subject: [PATCH 1/2] shrink const infer error
---
.../infer/error_reporting/need_type_info.rs | 15 ++++++++-----
.../cannot-infer-const-args.full.stderr | 0
.../cannot-infer-const-args.min.stderr | 0
.../{ => infer}/cannot-infer-const-args.rs | 0
.../infer/method-chain.full.stderr | 11 ++++++++++
.../infer/method-chain.min.stderr | 11 ++++++++++
.../ui/const-generics/infer/method-chain.rs | 22 +++++++++++++++++++
.../{ => infer}/uninferred-consts.full.stderr | 4 ++--
.../{ => infer}/uninferred-consts.min.stderr | 4 ++--
.../{ => infer}/uninferred-consts.rs | 0
10 files changed, 57 insertions(+), 10 deletions(-)
rename src/test/ui/const-generics/{ => infer}/cannot-infer-const-args.full.stderr (100%)
rename src/test/ui/const-generics/{ => infer}/cannot-infer-const-args.min.stderr (100%)
rename src/test/ui/const-generics/{ => infer}/cannot-infer-const-args.rs (100%)
create mode 100644 src/test/ui/const-generics/infer/method-chain.full.stderr
create mode 100644 src/test/ui/const-generics/infer/method-chain.min.stderr
create mode 100644 src/test/ui/const-generics/infer/method-chain.rs
rename src/test/ui/const-generics/{ => infer}/uninferred-consts.full.stderr (80%)
rename src/test/ui/const-generics/{ => infer}/uninferred-consts.min.stderr (80%)
rename src/test/ui/const-generics/{ => infer}/uninferred-consts.rs (100%)
diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index 4de84e5ba399c..9be234a7bb8bd 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -8,7 +8,7 @@ use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, Pat};
use rustc_middle::hir::map::Map;
use rustc_middle::ty::print::Print;
use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
-use rustc_middle::ty::{self, DefIdTree, Ty};
+use rustc_middle::ty::{self, DefIdTree, InferConst, Ty};
use rustc_span::source_map::DesugaringKind;
use rustc_span::symbol::kw;
use rustc_span::Span;
@@ -569,12 +569,15 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
local_visitor.visit_expr(expr);
}
+ let span = if let ty::ConstKind::Infer(InferConst::Var(vid)) = ct.val {
+ self.inner.borrow_mut().const_unification_table().probe_value(vid).origin.span
+ } else {
+ local_visitor.target_span
+ };
+
let error_code = error_code.into();
- let mut err = self.tcx.sess.struct_span_err_with_code(
- local_visitor.target_span,
- "type annotations needed",
- error_code,
- );
+ let mut err =
+ self.tcx.sess.struct_span_err_with_code(span, "type annotations needed", error_code);
err.note("unable to infer the value of a const parameter");
diff --git a/src/test/ui/const-generics/cannot-infer-const-args.full.stderr b/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
similarity index 100%
rename from src/test/ui/const-generics/cannot-infer-const-args.full.stderr
rename to src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
diff --git a/src/test/ui/const-generics/cannot-infer-const-args.min.stderr b/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
similarity index 100%
rename from src/test/ui/const-generics/cannot-infer-const-args.min.stderr
rename to src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
diff --git a/src/test/ui/const-generics/cannot-infer-const-args.rs b/src/test/ui/const-generics/infer/cannot-infer-const-args.rs
similarity index 100%
rename from src/test/ui/const-generics/cannot-infer-const-args.rs
rename to src/test/ui/const-generics/infer/cannot-infer-const-args.rs
diff --git a/src/test/ui/const-generics/infer/method-chain.full.stderr b/src/test/ui/const-generics/infer/method-chain.full.stderr
new file mode 100644
index 0000000000000..06e4c2e7bc6bc
--- /dev/null
+++ b/src/test/ui/const-generics/infer/method-chain.full.stderr
@@ -0,0 +1,11 @@
+error[E0282]: type annotations needed
+ --> $DIR/method-chain.rs:21:33
+ |
+LL | Foo.bar().bar().bar().bar().baz();
+ | ^^^
+ |
+ = note: unable to infer the value of a const parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/const-generics/infer/method-chain.min.stderr b/src/test/ui/const-generics/infer/method-chain.min.stderr
new file mode 100644
index 0000000000000..06e4c2e7bc6bc
--- /dev/null
+++ b/src/test/ui/const-generics/infer/method-chain.min.stderr
@@ -0,0 +1,11 @@
+error[E0282]: type annotations needed
+ --> $DIR/method-chain.rs:21:33
+ |
+LL | Foo.bar().bar().bar().bar().baz();
+ | ^^^
+ |
+ = note: unable to infer the value of a const parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0282`.
diff --git a/src/test/ui/const-generics/infer/method-chain.rs b/src/test/ui/const-generics/infer/method-chain.rs
new file mode 100644
index 0000000000000..b3184642f36b4
--- /dev/null
+++ b/src/test/ui/const-generics/infer/method-chain.rs
@@ -0,0 +1,22 @@
+// revisions: full min
+
+#![cfg_attr(full, feature(const_generics))]
+#![cfg_attr(full, allow(incomplete_features))]
+#![cfg_attr(min, feature(min_const_generics))]
+
+struct Foo;
+
+impl Foo {
+ fn bar(self) -> Foo {
+ Foo
+ }
+
+ fn baz<const N: usize>(self) -> Foo {
+ println!("baz: {}", N);
+ Foo
+ }
+}
+
+fn main() {
+ Foo.bar().bar().bar().bar().baz(); //~ ERROR type annotations needed
+}
\ No newline at end of file
diff --git a/src/test/ui/const-generics/uninferred-consts.full.stderr b/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
similarity index 80%
rename from src/test/ui/const-generics/uninferred-consts.full.stderr
rename to src/test/ui/const-generics/infer/uninferred-consts.full.stderr
index 2c5af9e65f827..6af49ba64523b 100644
--- a/src/test/ui/const-generics/uninferred-consts.full.stderr
+++ b/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
@@ -1,8 +1,8 @@
error[E0282]: type annotations needed
- --> $DIR/uninferred-consts.rs:14:5
+ --> $DIR/uninferred-consts.rs:14:9
|
LL | Foo.foo();
- | ^^^^^^^^^
+ | ^^^
|
= note: unable to infer the value of a const parameter
diff --git a/src/test/ui/const-generics/uninferred-consts.min.stderr b/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
similarity index 80%
rename from src/test/ui/const-generics/uninferred-consts.min.stderr
rename to src/test/ui/const-generics/infer/uninferred-consts.min.stderr
index 2c5af9e65f827..6af49ba64523b 100644
--- a/src/test/ui/const-generics/uninferred-consts.min.stderr
+++ b/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
@@ -1,8 +1,8 @@
error[E0282]: type annotations needed
- --> $DIR/uninferred-consts.rs:14:5
+ --> $DIR/uninferred-consts.rs:14:9
|
LL | Foo.foo();
- | ^^^^^^^^^
+ | ^^^
|
= note: unable to infer the value of a const parameter
diff --git a/src/test/ui/const-generics/uninferred-consts.rs b/src/test/ui/const-generics/infer/uninferred-consts.rs
similarity index 100%
rename from src/test/ui/const-generics/uninferred-consts.rs
rename to src/test/ui/const-generics/infer/uninferred-consts.rs
From 035f8791668406bc49fc315253835cbdec247549 Mon Sep 17 00:00:00 2001
From: Bastian Kauschke <bastian_kauschke@hotmail.de>
Date: Mon, 14 Sep 2020 10:08:32 +0200
Subject: [PATCH 2/2] improve const infer err
---
.../src/infer/error_reporting/need_type_info.rs | 14 ++++++++++++--
compiler/rustc_middle/src/infer/unify_key.rs | 1 +
.../infer/cannot-infer-const-args.full.stderr | 2 +-
.../infer/cannot-infer-const-args.min.stderr | 2 +-
.../const-generics/infer/method-chain.full.stderr | 2 +-
.../const-generics/infer/method-chain.min.stderr | 2 +-
src/test/ui/const-generics/infer/method-chain.rs | 2 +-
.../infer/uninferred-consts.full.stderr | 2 +-
.../infer/uninferred-consts.min.stderr | 2 +-
9 files changed, 20 insertions(+), 9 deletions(-)
diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index 9be234a7bb8bd..f87406c2ce469 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -6,6 +6,7 @@ use rustc_hir::def::{DefKind, Namespace};
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, Pat};
use rustc_middle::hir::map::Map;
+use rustc_middle::infer::unify_key::ConstVariableOriginKind;
use rustc_middle::ty::print::Print;
use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
use rustc_middle::ty::{self, DefIdTree, InferConst, Ty};
@@ -569,8 +570,13 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
local_visitor.visit_expr(expr);
}
+ let mut param_name = None;
let span = if let ty::ConstKind::Infer(InferConst::Var(vid)) = ct.val {
- self.inner.borrow_mut().const_unification_table().probe_value(vid).origin.span
+ let origin = self.inner.borrow_mut().const_unification_table().probe_value(vid).origin;
+ if let ConstVariableOriginKind::ConstParameterDefinition(param) = origin.kind {
+ param_name = Some(param);
+ }
+ origin.span
} else {
local_visitor.target_span
};
@@ -579,7 +585,11 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
let mut err =
self.tcx.sess.struct_span_err_with_code(span, "type annotations needed", error_code);
- err.note("unable to infer the value of a const parameter");
+ if let Some(param_name) = param_name {
+ err.note(&format!("cannot infer the value of the const parameter `{}`", param_name));
+ } else {
+ err.note("unable to infer the value of a const parameter");
+ }
err
}
diff --git a/compiler/rustc_middle/src/infer/unify_key.rs b/compiler/rustc_middle/src/infer/unify_key.rs
index 2580ac6bebd86..a60a17befeffd 100644
--- a/compiler/rustc_middle/src/infer/unify_key.rs
+++ b/compiler/rustc_middle/src/infer/unify_key.rs
@@ -124,6 +124,7 @@ pub struct ConstVariableOrigin {
pub enum ConstVariableOriginKind {
MiscVariable,
ConstInference,
+ // FIXME(const_generics): Consider storing the `DefId` of the param here.
ConstParameterDefinition(Symbol),
SubstitutionPlaceholder,
}
diff --git a/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr b/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
index 053139787edf9..84e75cc376416 100644
--- a/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
+++ b/src/test/ui/const-generics/infer/cannot-infer-const-args.full.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | foo();
| ^^^
|
- = note: unable to infer the value of a const parameter
+ = note: cannot infer the value of the const parameter `X`
error: aborting due to previous error
diff --git a/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr b/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
index 053139787edf9..84e75cc376416 100644
--- a/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
+++ b/src/test/ui/const-generics/infer/cannot-infer-const-args.min.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | foo();
| ^^^
|
- = note: unable to infer the value of a const parameter
+ = note: cannot infer the value of the const parameter `X`
error: aborting due to previous error
diff --git a/src/test/ui/const-generics/infer/method-chain.full.stderr b/src/test/ui/const-generics/infer/method-chain.full.stderr
index 06e4c2e7bc6bc..e65bc3f109681 100644
--- a/src/test/ui/const-generics/infer/method-chain.full.stderr
+++ b/src/test/ui/const-generics/infer/method-chain.full.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | Foo.bar().bar().bar().bar().baz();
| ^^^
|
- = note: unable to infer the value of a const parameter
+ = note: cannot infer the value of the const parameter `N`
error: aborting due to previous error
diff --git a/src/test/ui/const-generics/infer/method-chain.min.stderr b/src/test/ui/const-generics/infer/method-chain.min.stderr
index 06e4c2e7bc6bc..e65bc3f109681 100644
--- a/src/test/ui/const-generics/infer/method-chain.min.stderr
+++ b/src/test/ui/const-generics/infer/method-chain.min.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | Foo.bar().bar().bar().bar().baz();
| ^^^
|
- = note: unable to infer the value of a const parameter
+ = note: cannot infer the value of the const parameter `N`
error: aborting due to previous error
diff --git a/src/test/ui/const-generics/infer/method-chain.rs b/src/test/ui/const-generics/infer/method-chain.rs
index b3184642f36b4..9389ca20d106f 100644
--- a/src/test/ui/const-generics/infer/method-chain.rs
+++ b/src/test/ui/const-generics/infer/method-chain.rs
@@ -19,4 +19,4 @@ impl Foo {
fn main() {
Foo.bar().bar().bar().bar().baz(); //~ ERROR type annotations needed
-}
\ No newline at end of file
+}
diff --git a/src/test/ui/const-generics/infer/uninferred-consts.full.stderr b/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
index 6af49ba64523b..e47b6bd5dc691 100644
--- a/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
+++ b/src/test/ui/const-generics/infer/uninferred-consts.full.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | Foo.foo();
| ^^^
|
- = note: unable to infer the value of a const parameter
+ = note: cannot infer the value of the const parameter `N`
error: aborting due to previous error
diff --git a/src/test/ui/const-generics/infer/uninferred-consts.min.stderr b/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
index 6af49ba64523b..e47b6bd5dc691 100644
--- a/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
+++ b/src/test/ui/const-generics/infer/uninferred-consts.min.stderr
@@ -4,7 +4,7 @@ error[E0282]: type annotations needed
LL | Foo.foo();
| ^^^
|
- = note: unable to infer the value of a const parameter
+ = note: cannot infer the value of the const parameter `N`
error: aborting due to previous error