From a129a85144efb67bfd8f380a758ed6be41d3e29b Mon Sep 17 00:00:00 2001
From: Rob Pilling <robpilling@gmail.com>
Date: Sun, 16 Jan 2022 21:47:44 +0000
Subject: [PATCH] Handle generics with ParamEnv

---
 .../rustc_typeck/src/check/fn_ctxt/checks.rs  |  4 +--
 .../suggestions/args-instead-of-tuple.fixed   |  9 +++++
 .../ui/suggestions/args-instead-of-tuple.rs   |  9 +++++
 .../suggestions/args-instead-of-tuple.stderr  | 36 +++++++++++++++++--
 4 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
index a94e6b480d6..af0c9e5e509 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
@@ -18,7 +18,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::{ExprKind, Node, QPath};
 use rustc_middle::ty::adjustment::AllowTwoPhase;
 use rustc_middle::ty::fold::TypeFoldable;
-use rustc_middle::ty::{self, ParamEnv, Ty};
+use rustc_middle::ty::{self, Ty};
 use rustc_session::Session;
 use rustc_span::symbol::Ident;
 use rustc_span::{self, MultiSpan, Span};
@@ -514,7 +514,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let supplied_types: Vec<_> = provided_args.iter().map(|arg| self.check_expr(arg)).collect();
 
         let all_match = iter::zip(expected_types, supplied_types)
-            .all(|(expected, supplied)| self.can_eq(ParamEnv::empty(), expected, supplied).is_ok());
+            .all(|(expected, supplied)| self.can_eq(self.param_env, expected, supplied).is_ok());
 
         if all_match {
             match provided_args {
diff --git a/src/test/ui/suggestions/args-instead-of-tuple.fixed b/src/test/ui/suggestions/args-instead-of-tuple.fixed
index 095be95f185..c9b8a41d469 100644
--- a/src/test/ui/suggestions/args-instead-of-tuple.fixed
+++ b/src/test/ui/suggestions/args-instead-of-tuple.fixed
@@ -12,7 +12,16 @@ fn main() {
     //~^ ERROR this enum variant takes 1 argument but 0 arguments were supplied
 
     two_ints((1, 2)); //~ ERROR this function takes 1 argument
+
+    with_generic((3, 4)); //~ ERROR this function takes 1 argument
 }
 
 fn two_ints(_: (i32, i32)) {
 }
+
+fn with_generic<T: Copy + Send>((a, b): (i32, T)) {
+    if false {
+        // test generics/bound handling
+        with_generic((a, b)); //~ ERROR this function takes 1 argument
+    }
+}
diff --git a/src/test/ui/suggestions/args-instead-of-tuple.rs b/src/test/ui/suggestions/args-instead-of-tuple.rs
index 3466a46df84..d4cc3024dd0 100644
--- a/src/test/ui/suggestions/args-instead-of-tuple.rs
+++ b/src/test/ui/suggestions/args-instead-of-tuple.rs
@@ -12,7 +12,16 @@ fn main() {
     //~^ ERROR this enum variant takes 1 argument but 0 arguments were supplied
 
     two_ints(1, 2); //~ ERROR this function takes 1 argument
+
+    with_generic(3, 4); //~ ERROR this function takes 1 argument
 }
 
 fn two_ints(_: (i32, i32)) {
 }
+
+fn with_generic<T: Copy + Send>((a, b): (i32, T)) {
+    if false {
+        // test generics/bound handling
+        with_generic(a, b); //~ ERROR this function takes 1 argument
+    }
+}
diff --git a/src/test/ui/suggestions/args-instead-of-tuple.stderr b/src/test/ui/suggestions/args-instead-of-tuple.stderr
index 1bf7e7a8d17..172db7ee3df 100644
--- a/src/test/ui/suggestions/args-instead-of-tuple.stderr
+++ b/src/test/ui/suggestions/args-instead-of-tuple.stderr
@@ -38,7 +38,7 @@ LL |     two_ints(1, 2);
    |     ^^^^^^^^ -  - supplied 2 arguments
    |
 note: function defined here
-  --> $DIR/args-instead-of-tuple.rs:17:4
+  --> $DIR/args-instead-of-tuple.rs:19:4
    |
 LL | fn two_ints(_: (i32, i32)) {
    |    ^^^^^^^^ -------------
@@ -47,6 +47,38 @@ help: use parentheses to construct a tuple
 LL |     two_ints((1, 2));
    |              +    +
 
-error: aborting due to 4 previous errors
+error[E0061]: this function takes 1 argument but 2 arguments were supplied
+  --> $DIR/args-instead-of-tuple.rs:16:5
+   |
+LL |     with_generic(3, 4);
+   |     ^^^^^^^^^^^^ -  - supplied 2 arguments
+   |
+note: function defined here
+  --> $DIR/args-instead-of-tuple.rs:22:4
+   |
+LL | fn with_generic<T: Copy + Send>((a, b): (i32, T)) {
+   |    ^^^^^^^^^^^^                 ----------------
+help: use parentheses to construct a tuple
+   |
+LL |     with_generic((3, 4));
+   |                  +    +
+
+error[E0061]: this function takes 1 argument but 2 arguments were supplied
+  --> $DIR/args-instead-of-tuple.rs:25:9
+   |
+LL |         with_generic(a, b);
+   |         ^^^^^^^^^^^^ -  - supplied 2 arguments
+   |
+note: function defined here
+  --> $DIR/args-instead-of-tuple.rs:22:4
+   |
+LL | fn with_generic<T: Copy + Send>((a, b): (i32, T)) {
+   |    ^^^^^^^^^^^^                 ----------------
+help: use parentheses to construct a tuple
+   |
+LL |         with_generic((a, b));
+   |                      +    +
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0061`.