Add regression tests for issue 22443.

Fix rust-lang#22443.

Author: pnkfelix

src/test/compile-fail/dropck_no_diverge_on_nonregular_1.rs

@@ -0,0 +1,37 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Issue 22443: Reject code using non-regular types that would
+// otherwise cause dropck to loop infinitely.
+
+use std::marker::PhantomData;
+
+struct Digit<T> {
+    elem: T
+}
+
+struct Node<T:'static> { m: PhantomData<&'static T> }
+
+
+enum FingerTree<T:'static> {
+    Single(T),
+    // Bug report said Digit after Box would stack overflow (versus
+    // Digit before Box; see dropck_no_diverge_on_nonregular_2).
+    Deep(
+        Box<FingerTree<Node<T>>>,
+        Digit<T>,
+        )
+}
+
+fn main() {
+    let ft = //~ ERROR overflow while adding drop-check rules for FingerTree
+        FingerTree::Single(1);
+    //~^ ERROR overflow while adding drop-check rules for FingerTree
+}

src/test/compile-fail/dropck_no_diverge_on_nonregular_2.rs

@@ -0,0 +1,36 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Issue 22443: Reject code using non-regular types that would
+// otherwise cause dropck to loop infinitely.
+
+use std::marker::PhantomData;
+
+struct Digit<T> {
+    elem: T
+}
+
+struct Node<T:'static> { m: PhantomData<&'static T> }
+
+enum FingerTree<T:'static> {
+    Single(T),
+    // Bug report said Digit before Box would infinite loop (versus
+    // Digit after Box; see dropck_no_diverge_on_nonregular_1).
+    Deep(
+        Digit<T>,
+        Box<FingerTree<Node<T>>>,
+        )
+}
+
+fn main() {
+    let ft = //~ ERROR overflow while adding drop-check rules for FingerTree
+        FingerTree::Single(1);
+    //~^ ERROR overflow while adding drop-check rules for FingerTree
+}

src/test/compile-fail/dropck_no_diverge_on_nonregular_3.rs

@@ -0,0 +1,46 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Issue 22443: Reject code using non-regular types that would
+// otherwise cause dropck to loop infinitely.
+//
+// This version is just checking that we still sanely handle a trivial
+// wrapper around the non-regular type. (It also demonstrates how the
+// error messages will report different types depending on which type
+// dropck is analyzing.)
+
+use std::marker::PhantomData;
+
+struct Digit<T> {
+    elem: T
+}
+
+struct Node<T:'static> { m: PhantomData<&'static T> }
+
+enum FingerTree<T:'static> {
+    Single(T),
+    // According to the bug report, Digit before Box would infinite loop.
+    Deep(
+        Digit<T>,
+        Box<FingerTree<Node<T>>>,
+        )
+}
+
+enum Wrapper<T:'static> {
+    Simple,
+    Other(FingerTree<T>),
+}
+
+fn main() {
+    let w = //~ ERROR overflow while adding drop-check rules for core::option
+        Some(Wrapper::Simple::<u32>);
+    //~^ ERROR overflow while adding drop-check rules for core::option::Option
+    //~| ERROR overflow while adding drop-check rules for Wrapper
+}

src/test/run-pass/issue-22777.rs

@@ -0,0 +1,55 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// This test is reduced from libsyntax.  It is just checking that we
+// can successfully deal with a "deep" structure, which the drop-check
+// was hitting a recursion limit on at one point.
+
+#![allow(non_camel_case_types)]
+
+pub fn noop_fold_impl_item() -> SmallVector<ImplItem> {
+    loop  { }
+}
+
+pub struct SmallVector<T>(P<T>);
+pub struct ImplItem(P<S01_Method>);
+
+struct P<T>(Box<T>);
+
+struct S01_Method(P<S02_Generics>);
+struct S02_Generics(P<S03_TyParam>);
+struct S03_TyParam(P<S04_TyParamBound>);
+struct S04_TyParamBound(S05_PolyTraitRef);
+struct S05_PolyTraitRef(S06_TraitRef);
+struct S06_TraitRef(S07_Path);
+struct S07_Path(Vec<S08_PathSegment>);
+struct S08_PathSegment(S09_PathParameters);
+struct S09_PathParameters(P<S10_ParenthesizedParameterData>);
+struct S10_ParenthesizedParameterData(Option<P<S11_Ty>>);
+struct S11_Ty(P<S12_Expr>);
+struct S12_Expr(P<S13_Block>);
+struct S13_Block(Vec<P<S14_Stmt>>);
+struct S14_Stmt(P<S15_Decl>);
+struct S15_Decl(P<S16_Local>);
+struct S16_Local(P<S17_Pat>);
+struct S17_Pat(P<S18_Mac>);
+struct S18_Mac(Vec<P<S19_TokenTree>>);
+struct S19_TokenTree(P<S20_Token>);
+struct S20_Token(P<S21_Nonterminal>);
+struct S21_Nonterminal(P<S22_Item>);
+struct S22_Item(P<S23_EnumDef>);
+struct S23_EnumDef(Vec<P<S24_Variant>>);
+struct S24_Variant(P<S25_VariantKind>);
+struct S25_VariantKind(P<S26_StructDef>);
+struct S26_StructDef(Vec<P<S27_StructField>>);
+struct S27_StructField(P<S28_StructFieldKind>);
+struct S28_StructFieldKind;
+
+pub fn main() {}