llvm/clang/test/CXX/dcl.dcl/dcl.spec/dcl.typedef/p3.cpp

// RUN: %clang_cc1 -verify %s

typedef struct s { int x; } s;
typedef int I;
typedef int I2;
typedef I2 I; // expected-note {{previous definition is here}}

typedef char I; // expected-error {{typedef redefinition with different types}}