fix Issue 17489 - ICE in ddmd/argtypes.d

[WalterBright]

This replaces #6902 by moving the check to where it should be - errors should propagate up the AST.

[dlang-bot]

Thanks for your pull request, @WalterBright!

Bugzilla references

Fix	Bugzilla	Description
✓	17489	ICE in ddmd/argtypes.d

[WalterBright]

Why would the circleci fail where the autotester passes?

[ibuclaw]

 ... fail_compilation/fail301.d     ()
Test failed.  The logged output:
../src/dmd -conf= -m64 -Ifail_compilation -verrors=0   -odtest_results/fail_compilation -oftest_results/fail_compilation/fail301_0.o -c fail_compilation/fail301.d
fail_compilation/fail301.d(11): Error: need 'this' for 'guard' of type 'int'
core.exception.AssertError@ddmd/argtypes.d(201): Assertion failure
----------------
??:? _d_assertp [0x786878]
??:? _ZN10toArgTypes10ToArgTypes12argtypemergeEP4TypeS2_j [0x5046f4]
??:? _ZN10toArgTypes10ToArgTypes5visitEP10TypeStruct [0x5050a1]
??:? _ZN10TypeStruct6acceptEP7Visitor [0x642a52]
??:? _Z10toArgTypesP4Type [0x5040f9]
??:? _ZN17StructDeclaration12finalizeSizeEv [0x591f7f]
??:? _ZN20AggregateDeclaration13determineSizeE3Loc [0x501be2]
??:? _ZN20AggregateDeclaration9semantic2EP5Scope [0x5012f1]
??:? _ZN16TemplateInstance9semantic2EP5Scope [0x5ab224]
??:? _ZN17StructDeclaration8semanticEP5Scope [0x591852]
??:? _ZN6Module19runDeferredSemanticEv [0x58412a]
??:? _ZN16TemplateInstance13expandMembersEP5Scope [0x5b0168]
??:? _ZN16TemplateInstance16tryExpandMembersEP5Scope [0x5b01ea]
??:? _ZN16TemplateInstance8semanticEP5ScopeP5ArrayIP10ExpressionE [0x5aa680]
??:? _ZN16TemplateInstance8semanticEP5Scope [0x5ab051]
??:? _ZN12TypeInstance7resolveE3LocP5ScopePP10ExpressionPP4TypePP7Dsymbolb [0x63f5b9]
??:? _ZN12TypeInstance8semanticE3LocP5Scope [0x63f6d4]
??:? _ZN14VarDeclaration8semanticEP5Scope [0x543e88]
??:? _ZN14DeclarationExp8semanticEP5Scope [0x5cd678]
??:? _ZN24StatementSemanticVisitor5visitEP12ExpStatement [0x6833bd]
??:? _ZN12ExpStatement6acceptEP7Visitor [0x67517b]
??:? ddmd.statement.Statement ddmd.statementsem.semantic(ddmd.statement.Statement, ddmd.dscope.Scope*) [0x693c2c]
??:? _ZN24StatementSemanticVisitor5visitEP17CompoundStatement [0x683705]
??:? _ZN17CompoundStatement6acceptEP7Visitor [0x675aa7]
??:? ddmd.statement.Statement ddmd.statementsem.semantic(ddmd.statement.Statement, ddmd.dscope.Scope*) [0x693c2c]
??:? _ZN15FuncDeclaration9semantic3EP5Scope [0x5f5113]
??:? _ZN6Module9semantic3EP5Scope [0x583bc9]
??:? int ddmd.mars.tryMain(ulong, const(char)**) [0x628287]
??:? _Dmain [0x629628]


==============================
Test failed: 
expected:
----
fail_compilation/fail301.d(11): Error: need 'this' for 'guard' of type 'int'
fail_compilation/fail301.d(22): Error: template instance fail301.bug3305!0 error instantiating
----
actual:
----
fail_compilation/fail301.d(11): Error: need 'this' for 'guard' of type 'int'
core.exception.AssertError@ddmd/argtypes.d(201): Assertion failure
----------------
??:? _d_assertp [0x786878]
??:? _ZN10toArgTypes10ToArgTypes12argtypemergeEP4TypeS2_j [0x5046f4]
??:? _ZN10toArgTypes10ToArgTypes5visitEP10TypeStruct [0x5050a1]
??:? _ZN10TypeStruct6acceptEP7Visitor [0x642a52]
??:? _Z10toArgTypesP4Type [0x5040f9]
??:? _ZN17StructDeclaration12finalizeSizeEv [0x591f7f]
??:? _ZN20AggregateDeclaration13determineSizeE3Loc [0x501be2]
??:? _ZN20AggregateDeclaration9semantic2EP5Scope [0x5012f1]
??:? _ZN16TemplateInstance9semantic2EP5Scope [0x5ab224]
??:? _ZN17StructDeclaration8semanticEP5Scope [0x591852]
??:? _ZN6Module19runDeferredSemanticEv [0x58412a]
??:? _ZN16TemplateInstance13expandMembersEP5Scope [0x5b0168]
??:? _ZN16TemplateInstance16tryExpandMembersEP5Scope [0x5b01ea]
??:? _ZN16TemplateInstance8semanticEP5ScopeP5ArrayIP10ExpressionE [0x5aa680]
??:? _ZN16TemplateInstance8semanticEP5Scope [0x5ab051]
??:? _ZN12TypeInstance7resolveE3LocP5ScopePP10ExpressionPP4TypePP7Dsymbolb [0x63f5b9]
??:? _ZN12TypeInstance8semanticE3LocP5Scope [0x63f6d4]
??:? _ZN14VarDeclaration8semanticEP5Scope [0x543e88]
??:? _ZN14DeclarationExp8semanticEP5Scope [0x5cd678]
??:? _ZN24StatementSemanticVisitor5visitEP12ExpStatement [0x6833bd]
??:? _ZN12ExpStatement6acceptEP7Visitor [0x67517b]
??:? ddmd.statement.Statement ddmd.statementsem.semantic(ddmd.statement.Statement, ddmd.dscope.Scope*) [0x693c2c]
??:? _ZN24StatementSemanticVisitor5visitEP17CompoundStatement [0x683705]
??:? _ZN17CompoundStatement6acceptEP7Visitor [0x675aa7]
??:? ddmd.statement.Statement ddmd.statementsem.semantic(ddmd.statement.Statement, ddmd.dscope.Scope*) [0x693c2c]
??:? _ZN15FuncDeclaration9semantic3EP5Scope [0x5f5113]
??:? _ZN6Module9semantic3EP5Scope [0x583bc9]
??:? int ddmd.mars.tryMain(ulong, const(char)**) [0x628287]
??:? _Dmain [0x629628]
----

[ibuclaw]

Essentially, my complaint in #6746. All other testers build with asserts turned off.

[WalterBright]

Thanks, @ibuclaw , I can repro it now.

[WalterBright]

@ibuclaw this is ready to rock now