Reimplement the structural-equality checks used to determine whether
two types in different AST contexts are equivalent. Rather than
transforming the type from one context into the other context, we
perform a deep structural comparison of the types. This change
addresses a serious problem with recursive data types like

  struct ListNode {
    int value;
    struct ListNode *Next;
  } xList;



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@96278 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/ASTMerge/Inputs/struct1.c b/test/ASTMerge/Inputs/struct1.c
index 10c8fce..e6d71ac 100644
--- a/test/ASTMerge/Inputs/struct1.c
+++ b/test/ASTMerge/Inputs/struct1.c
@@ -44,10 +44,14 @@
 // Incomplete type
 struct S10 *x10;
 
-// FIXME: Matches, but crashes the importer
-#if 0
+// Matches
 struct ListNode {
   int value;
   struct ListNode *Next;
 } xList;
-#endif
+
+// Mismatch due to struct used internally
+struct DeepError {
+  int value;
+  struct DeeperError { int i; int f; } *Deeper;
+} xDeep;
diff --git a/test/ASTMerge/Inputs/struct2.c b/test/ASTMerge/Inputs/struct2.c
index 655efd4..4022831 100644
--- a/test/ASTMerge/Inputs/struct2.c
+++ b/test/ASTMerge/Inputs/struct2.c
@@ -46,3 +46,9 @@
   int value;
   struct ListNode *Next;
 } xList;
+
+// Mismatch due to struct used internally
+struct DeepError {
+  int value;
+  struct DeeperError { int i; float f; } *Deeper;
+} xDeep;
diff --git a/test/ASTMerge/struct.c b/test/ASTMerge/struct.c
index c6e5718..d71436f 100644
--- a/test/ASTMerge/struct.c
+++ b/test/ASTMerge/struct.c
@@ -31,4 +31,9 @@
 // CHECK: struct2.c:33:33: note: bit-field 'j' with type 'unsigned int' and length 16 here
 // CHECK: struct2.c:33:43: error: external variable 'x7' declared with incompatible types in different translation units ('struct S7' vs. 'struct S7')
 // CHECK: struct1.c:36:42: note: declared here with type 'struct S7'
-// CHECK: 29 diagnostics
+// CHECK: struct1.c:56:10: warning: type 'struct DeeperError' has incompatible definitions in different translation units
+// CHECK: struct1.c:56:35: note: field 'f' has type 'int' here
+// CHECK: struct2.c:53:37: note: field 'f' has type 'float' here
+// CHECK: struct2.c:54:3: error: external variable 'xDeep' declared with incompatible types in different translation units ('struct DeepError' vs. 'struct DeepError')
+// CHECK: struct1.c:57:3: note: declared here with type 'struct DeepError'
+// CHECK: 37 diagnostics