From 3f17dae37d8829a03312340918a839f0bf8b6088 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Fri, 4 Mar 2022 20:28:35 -0800
Subject: [PATCH] check extra args even if the function is not c_variadic

---
 .../rustc_typeck/src/check/fn_ctxt/checks.rs  | 22 ++++++++++---------
 src/test/ui/tuple/wrong_argument_ice-4.rs     |  6 +++++
 src/test/ui/tuple/wrong_argument_ice-4.stderr | 15 +++++++++++++
 3 files changed, 33 insertions(+), 10 deletions(-)
 create mode 100644 src/test/ui/tuple/wrong_argument_ice-4.rs
 create mode 100644 src/test/ui/tuple/wrong_argument_ice-4.stderr

diff --git a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
index 3f6247facd1a2..f165093c958db 100644
--- a/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
+++ b/compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
@@ -281,6 +281,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.demand_suptype(provided_arg.span, formal_input_ty, coerced_ty);
         };
 
+        let minimum_input_count = formal_input_tys.len();
+
         // Check the arguments.
         // We do this in a pretty awful way: first we type-check any arguments
         // that are not closures, then we type-check the closures. This is so
@@ -303,7 +305,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 })
             }
 
-            let minimum_input_count = formal_input_tys.len();
             for (idx, arg) in provided_args.iter().enumerate() {
                 // Warn only for the first loop (the "no closures" one).
                 // Closure arguments themselves can't be diverging, but
@@ -456,17 +457,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             err.emit();
         }
 
-        // We also need to make sure we at least write the ty of the other
-        // arguments which we skipped above.
-        if c_variadic {
-            fn variadic_error<'tcx>(sess: &Session, span: Span, ty: Ty<'tcx>, cast_ty: &str) {
-                use crate::structured_errors::MissingCastForVariadicArg;
+        for arg in provided_args.iter().skip(minimum_input_count) {
+            let arg_ty = self.check_expr(&arg);
 
-                MissingCastForVariadicArg { sess, span, ty, cast_ty }.diagnostic().emit();
-            }
+            if c_variadic {
+                // We also need to make sure we at least write the ty of the other
+                // arguments which we skipped above, either because they were additional
+                // c_variadic args, or because we had an argument count mismatch.
+                fn variadic_error<'tcx>(sess: &Session, span: Span, ty: Ty<'tcx>, cast_ty: &str) {
+                    use crate::structured_errors::MissingCastForVariadicArg;
 
-            for arg in provided_args.iter().skip(expected_arg_count) {
-                let arg_ty = self.check_expr(&arg);
+                    MissingCastForVariadicArg { sess, span, ty, cast_ty }.diagnostic().emit();
+                }
 
                 // There are a few types which get autopromoted when passed via varargs
                 // in C but we just error out instead and require explicit casts.
diff --git a/src/test/ui/tuple/wrong_argument_ice-4.rs b/src/test/ui/tuple/wrong_argument_ice-4.rs
new file mode 100644
index 0000000000000..479bd0d819fdb
--- /dev/null
+++ b/src/test/ui/tuple/wrong_argument_ice-4.rs
@@ -0,0 +1,6 @@
+fn main() {
+    (|| {})(|| {
+        //~^ ERROR this function takes 0 arguments but 1 argument was supplied
+        let b = 1;
+    });
+}
diff --git a/src/test/ui/tuple/wrong_argument_ice-4.stderr b/src/test/ui/tuple/wrong_argument_ice-4.stderr
new file mode 100644
index 0000000000000..fef5dca856db3
--- /dev/null
+++ b/src/test/ui/tuple/wrong_argument_ice-4.stderr
@@ -0,0 +1,15 @@
+error[E0057]: this function takes 0 arguments but 1 argument was supplied
+  --> $DIR/wrong_argument_ice-4.rs:2:5
+   |
+LL |       (|| {})(|| {
+   |  _____^^^^^^^_-
+   | |     |
+   | |     expected 0 arguments
+LL | |
+LL | |         let b = 1;
+LL | |     });
+   | |_____- supplied 1 argument
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0057`.