Bug 20604 – [ICE] dtoh ICE with nested template structs (and probably most templates

dtoh currently doesn't seem to have much handling of templates. It ignore trivial cases of templated functions, but nesting defeats it quite easily and triggers an ICE: ``` extern(C++) { struct Foo (T) { T val; } struct Bar (T) { Foo!T v; } } ``` Triggers: ``` ./generated/osx/release/64/dmd -HC -c foo.d Invalid type: Foo!T --- ERROR: This is a compiler bug. Please report it via https://issues.dlang.org/enter_bug.cgi with, preferably, a reduced, reproducible example and the information below. DustMite (https://github.com/CyberShadow/DustMite/wiki) can help with the reduction. --- DMD v2.090.1-244-gca55eb392 predefs DigitalMars Posix OSX CppRuntime_Clang darwin LittleEndian D_Version2 all D_SIMD D_InlineAsm_X86_64 X86_64 D_LP64 D_PIC assert D_ModuleInfo D_Exceptions D_TypeInfo D_HardFloat D_ObjectiveC binary ./generated/osx/release/64/dmd version v2.090.1-244-gca55eb392 config ./generated/osx/release/64/dmd.conf DFLAGS -I./generated/osx/release/64/../../../../../druntime/import -I./generated/osx/release/64/../../../../../phobos -L-L./generated/osx/release/64/../../../../../phobos/generated/osx/release/64 -fPIC --- core.exception.AssertError@dmd/dtoh.d(1096): Assertion failure ---------------- ??:? _d_assertp [0x1081a1bd5] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE5visitEP4Type [0x107f7737c] dmd/access.d:393 _ZN16ParseTimeVisitorI10ASTCodegenE5visitEP13TypeQualified [0x108055c26] dmd/access.d:393 _ZN16ParseTimeVisitorI10ASTCodegenE5visitEP12TypeInstance [0x108055e59] dmd/access.d:393 _ZN12TypeInstance6acceptEP7Visitor [0x108025f41] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE12typeToBufferEP4TypeP10Identifier [0x107f77280] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE5visitEP14VarDeclaration [0x107f75877] dmd/access.d:393 _ZN14VarDeclaration6acceptEP7Visitor [0x107f0b7f1] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE5visitEP19TemplateDeclaration [0x107f7829e] dmd/access.d:393 _ZN19TemplateDeclaration6acceptEP7Visitor [0x107f65c59] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE5visitEP17AttribDeclaration [0x107f74d43] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE5visitEP15LinkDeclaration [0x107f74dcf] dmd/access.d:393 _ZN15LinkDeclaration6acceptEP7Visitor [0x107ed4d19] dmd/access.d:393 _ZN11ToCppBufferI10ASTCodegenE5visitEP6Module [0x107f74e5f] dmd/access.d:393 _ZN6Module6acceptEP7Visitor [0x107f2d9a9] dmd/access.d:393 _Z14genCppHdrFilesR5ArrayIP6ModuleE [0x107f7498a] dmd/access.d:393 int dmd.mars.tryMain(ulong, const(char)**, ref dmd.globals.Param) [0x108013802] dmd/access.d:393 _Dmain [0x1080147cf] ```

@MoonlightSentinel created dlang/dmd pull request #11875 "Fix 20604 - [ICE] dtoh ICE with nested template structs" fixing this issue: - Fix 20604 - [ICE] dtoh ICE with nested template structs Define a handler for TypeInstance and handle potentially missing template identifiers https://github.com/dlang/dmd/pull/11875

dlang/dmd pull request #11875 "Fix 20604 - [ICE] dtoh ICE with nested template structs" was merged into master: - bf4d9dc5b4c13dfc5e8c98b065af8a12956c2876 by MoonlightSentinel: Fix 20604 - [ICE] dtoh ICE with nested template structs Define a handler for TypeInstance and handle potentially missing template identifiers https://github.com/dlang/dmd/pull/11875