Compiler crash on missing function body via interface with type parameter

[jmillikin]

package main

type Message[T any] interface {
	isMessage(T)
}

type IsGeneratedMessage[T any] struct{}

func (IsGeneratedMessage[T]) isMessage(T)

type HelloMsg struct {
	IsGeneratedMessage[HelloMsg]
}

func printSize[T any](message Message[T]) {
}

func main() {
	printSize(&HelloMsg{})
}

% go version
go version go1.23.1 darwin/arm64
% go build -o main
# example.com/example
./main.go:9:6: missing function body

% tinygo version
tinygo version 0.33.0 darwin/arm64 (using go version go1.23.1 and LLVM version 18.1.2)
% tinygo build -o main         
panic: runtime error: index out of range [0] with length 0

goroutine 82 [running]:
github.com/tinygo-org/tinygo/compiler.(*builder).createFunctionStart(0x14000022900, 0x0)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1207 +0xdf0
github.com/tinygo-org/tinygo/compiler.(*builder).createFunction(0x14000022900)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1296 +0x2c
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getFunction(0x14000194000, 0x14000896400)
	/Users/runner/work/tinygo/tinygo/compiler/symbol.go:224 +0xc94
github.com/tinygo-org/tinygo/compiler.(*builder).createFunctionCall(0x14000022780, 0x1400362d340)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1870 +0x978
github.com/tinygo-org/tinygo/compiler.(*builder).createExpr(0x14000022780, {0x1088b7900, 0x1400362d300})
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:2035 +0x1ebc
github.com/tinygo-org/tinygo/compiler.(*builder).createInstruction(0x14000022780, {0x1088b77e0, 0x1400362d300})
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1448 +0x898
github.com/tinygo-org/tinygo/compiler.(*builder).createFunction(0x14000022780)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1337 +0x6a8
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getFunction(0x14000194000, 0x14000896800)
	/Users/runner/work/tinygo/tinygo/compiler/symbol.go:224 +0xc94
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getTypeMethodSet(0x14000194000, {0x1088b3f08, 0x140035b8b10})
	/Users/runner/work/tinygo/tinygo/compiler/interface.go:621 +0x1d4
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getTypeCode(0x14000194000, {0x1088b3f08, 0x140035b8b10})
	/Users/runner/work/tinygo/tinygo/compiler/interface.go:420 +0x2bdc
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getTypeCode(0x14000194000, {0x1088b3ee0, 0x140046f08d0})
	/Users/runner/work/tinygo/tinygo/compiler/interface.go:355 +0x24a0
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getTypeCode(0x14000194000, {0x1088b3c60, 0x140000f64d0})
	/Users/runner/work/tinygo/tinygo/compiler/interface.go:295 +0x2300
github.com/tinygo-org/tinygo/compiler.(*compilerContext).getTypeCode(0x14000194000, {0x1088b3f08, 0x1400358a7e0})
	/Users/runner/work/tinygo/tinygo/compiler/interface.go:325 +0x29b0
github.com/tinygo-org/tinygo/compiler.(*builder).createMakeInterface(0x14000022600, {0x1088b7870?}, {0x1088b3f08, 0x1400358a7e0}, 0x2?)
	/Users/runner/work/tinygo/tinygo/compiler/interface.go:80 +0x6c
github.com/tinygo-org/tinygo/compiler.(*builder).createExpr(0x14000022600, {0x1088b76c0, 0x14003df3a40})
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:2219 +0x1890
github.com/tinygo-org/tinygo/compiler.(*builder).createInstruction(0x14000022600, {0x1088b87a0, 0x14003df3a40})
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1448 +0x898
github.com/tinygo-org/tinygo/compiler.(*builder).createFunction(0x14000022600)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:1337 +0x6a8
github.com/tinygo-org/tinygo/compiler.(*compilerContext).createPackage(0x14000194000, {0x14000175c00?}, 0x14003c23880)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:853 +0x3a4
github.com/tinygo-org/tinygo/compiler.CompilePackage({0x1400344d8f0?, 0x61?}, 0x1400347ba40, 0x14003c23880, {0x10111b6ffada033c?}, 0x1070d2913?, 0x68?)
	/Users/runner/work/tinygo/tinygo/compiler/compiler.go:312 +0x394
github.com/tinygo-org/tinygo/builder.Build.func3(0x140049d2cc0)
	/Users/runner/work/tinygo/tinygo/builder/build.go:375 +0x18c
github.com/tinygo-org/tinygo/builder.runJob(0x140049d2cc0, 0x140048c6000)
	/Users/runner/work/tinygo/tinygo/builder/jobs.go:222 +0x48
created by github.com/tinygo-org/tinygo/builder.runJobs in goroutine 1
	/Users/runner/work/tinygo/tinygo/builder/jobs.go:123 +0x43c