gcc/testsuite/gdc.test/fail_compilation/fail11751.d

/*
TEST_OUTPUT:
---
fail_compilation/fail11751.d(10): Error: missing exponent
fail_compilation/fail11751.d(10): Error: semicolon expected following auto declaration, not `ABC`
fail_compilation/fail11751.d(10): Error: no identifier for declarator `ABC`
---
*/

auto x = 0x1.FFFFFFFFFFFFFpABC;