super[<expr>] fails when expr is not a variable reference

[mkmik]

Jsonnet version:

$ jsonnet --version
Jsonnet commandline interpreter (Go implementation) v0.19.1

super[variable] works:

$ jsonnet -e '{a:1} + {local c=$.c, s: super[c], c: "a"}' 
{
   "a": 1,
   "c": "a",
   "s": 1
}

super[$.field] crashes:

$ jsonnet -e '{a:1} + {s: super[$.c], c: "a"}' 
INTERNAL ERROR: (CRASH) Unexpected node &ast.Dollar{NodeBase:ast.NodeBase{Fodder:ast.Fodder{}, Ctx:(ast.Context)(nil), FreeVars:ast.Identifiers{}, LocRange:ast.LocationRange{File:(*ast.Source)(0x14000091440), FileName:"", Begin:ast.Location{Line:1, Column:19}, End:ast.Location{Line:1, Column:20}}}}
goroutine 1 [running]:
runtime/debug.Stack()
        /opt/homebrew/Cellar/go/1.19.2/libexec/src/runtime/debug/stack.go:24 +0x64
github.com/google/go-jsonnet.(*VM).evaluateSnippet.func1()
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/vm.go:214 +0x3c
panic({0x100fa5760, 0x1400008e7f0})
        /opt/homebrew/Cellar/go/1.19.2/libexec/src/runtime/panic.go:884 +0x204
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x100fd3500?, 0x140000bb5e0}, 0x1, 0x100eb8dc8?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:155 +0xaa0
github.com/google/go-jsonnet/internal/program.visitNext({0x100fd3500, 0x140000bb5e0}, 0x0?, 0x0?, 0x140001f56b8)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x100fd36f8?, 0x1400009a8f0}, 0x1, 0x100eb8dc8?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:105 +0x718
github.com/google/go-jsonnet/internal/program.visitNext({0x100fd36f8, 0x1400009a8f0}, 0x0?, 0x0?, 0x140001f6008)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x100fd3a10?, 0x140000fe000}, 0x1, 0x0?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:103 +0x3f4
github.com/google/go-jsonnet/internal/program.visitNext({0x100fd3a10, 0x140000fe000}, 0x3a?, 0x1?, 0x140001f6958)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x100fd34b8?, 0x140000fe180}, 0x0, 0x100eb8dc8?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:127 +0xfc8
github.com/google/go-jsonnet/internal/program.visitNext({0x100fd34b8, 0x140000fe180}, 0x12?, 0x140000a8090?, 0x140001f72a8)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x100fd3428?, 0x140000e8420}, 0x0, 0x4?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:70 +0x3a8
github.com/google/go-jsonnet/internal/program.analyze({0x100fd3428, 0x140000e8420})
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:165 +0x128
github.com/google/go-jsonnet/internal/program.SnippetToAST({0x100f30c0f?, 0x16f02afb3?}, {0x0?, 0x100f2b4c4?}, {0x16f02afb3?, 0x14000090150?})
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/program.go:19 +0x5c
github.com/google/go-jsonnet.(*VM).evaluateSnippet(0x140001f7f00, {0x100f30c0f?, 0x0?}, {0x0?, 0x140000dbd38?}, {0x16f02afb3?, 0x28?}, 0x0)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/vm.go:217 +0x84
github.com/google/go-jsonnet.(*VM).EvaluateAnonymousSnippet(0x140001f7f00, {0x100f30c0f?, 0x14000070da8?}, {0x16f02afb3?, 0x140000dbf00?})
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/vm.go:371 +0x3c
main.main()
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/cmd/jsonnet/cmd.go:450 +0x66c

Please report a bug here: https://github.com/google/go-jsonnet/issues

super[self.field] crashes:

$ jsonnet -e '{a:1} + {s: super[self.c], c: "a"}'
INTERNAL ERROR: (CRASH) Unexpected node <nil>
goroutine 1 [running]:
runtime/debug.Stack()
        /opt/homebrew/Cellar/go/1.19.2/libexec/src/runtime/debug/stack.go:24 +0x64
github.com/google/go-jsonnet.(*VM).evaluateSnippet.func1()
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/vm.go:214 +0x3c
panic({0x104e45760, 0x140001107e0})
        /opt/homebrew/Cellar/go/1.19.2/libexec/src/runtime/panic.go:884 +0x204
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x0?, 0x0}, 0x1, 0x104d58dc8?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:155 +0xaa0
github.com/google/go-jsonnet/internal/program.visitNext({0x0, 0x0}, 0x0?, 0x0?, 0x140002756b8)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x104e736f8?, 0x1400011c8f0}, 0x1, 0x104d58dc8?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:106 +0x734
github.com/google/go-jsonnet/internal/program.visitNext({0x104e736f8, 0x1400011c8f0}, 0x0?, 0x0?, 0x14000276008)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x104e73a10?, 0x14000180000}, 0x1, 0x0?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:103 +0x3f4
github.com/google/go-jsonnet/internal/program.visitNext({0x104e73a10, 0x14000180000}, 0x3a?, 0x1?, 0x14000276958)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x104e734b8?, 0x14000180180}, 0x0, 0x104d58dc8?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:127 +0xfc8
github.com/google/go-jsonnet/internal/program.visitNext({0x104e734b8, 0x14000180180}, 0x12?, 0x1400012a090?, 0x140002772a8)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:35 +0x38
github.com/google/go-jsonnet/internal/program.analyzeVisit({0x104e73428?, 0x14000168420}, 0x0, 0x4?)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:70 +0x3a8
github.com/google/go-jsonnet/internal/program.analyze({0x104e73428, 0x14000168420})
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/static_analyzer.go:165 +0x128
github.com/google/go-jsonnet/internal/program.SnippetToAST({0x104dd0c0f?, 0x16b18afb3?}, {0x0?, 0x104dcb4c4?}, {0x16b18afb3?, 0x14000112150?})
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/internal/program/program.go:19 +0x5c
github.com/google/go-jsonnet.(*VM).evaluateSnippet(0x14000277f00, {0x104dd0c0f?, 0x0?}, {0x0?, 0x1400015bd38?}, {0x16b18afb3?, 0x28?}, 0x0)
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/vm.go:217 +0x84
github.com/google/go-jsonnet.(*VM).EvaluateAnonymousSnippet(0x14000277f00, {0x104dd0c0f?, 0x14000070da8?}, {0x16b18afb3?, 0x1400015bf00?})
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/vm.go:371 +0x3c
main.main()
        /private/tmp/go-jsonnet-20221028-94917-fg07tm/go-jsonnet-0.19.1/cmd/jsonnet/cmd.go:450 +0x66c

Please report a bug here: https://github.com/google/go-jsonnet/issues