2 commits

Author	SHA1	Message	Date
Anna Shaleva	91b36657d6	compiler: do not emit code for unnamed unused variables ... If variable is unnamed and does not contain function call then it's treated as unused and code generation may be omitted for it initialization/declaration.	2022-09-01 09:18:56 +03:00
Anna Shaleva	07ee7f7e12	compiler: allow multi-return variables declaration ... Problem: an attempt to compile the following code leads to a runtime panic: ``` package foo var a, b = f() func Main() int { return a + b } func f() (int, int) { return 1, 2 } ``` ``` panic: runtime error: index out of range [1] with length 1 [recovered] panic: runtime error: index out of range [1] with length 1 goroutine 22 [running]: testing.tRunner.func1.2({0xa341c0, 0xc0001647f8}) /usr/local/go/src/testing/testing.go:1209 +0x24e testing.tRunner.func1() /usr/local/go/src/testing/testing.go:1212 +0x218 panic({0xa341c0, 0xc0001647f8}) /usr/local/go/src/runtime/panic.go:1038 +0x215 github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).Visit(0xc0001623c0, {0xc75520, 0xc000155d80}) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:591 +0x6559 go/ast.Walk({0xc6c4e0, 0xc0001623c0}, {0xc75520, 0xc000155d80}) /usr/local/go/src/go/ast/walk.go:50 +0x5f github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).convertGlobals.func1({0xc75520, 0xc000155d80}) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:359 +0x70 go/ast.inspector.Visit(0xc000229740, {0xc75520, 0xc000155d80}) /usr/local/go/src/go/ast/walk.go:375 +0x31 go/ast.Walk({0xc6d920, 0xc000229740}, {0xc75520, 0xc000155d80}) /usr/local/go/src/go/ast/walk.go:50 +0x5f go/ast.walkDeclList({0xc6d920, 0xc000229740}, {0xc000155e80, 0x3, 0x120}) /usr/local/go/src/go/ast/walk.go:36 +0x87 go/ast.Walk({0xc6d920, 0xc000229740}, {0xc75458, 0xc000156c80}) /usr/local/go/src/go/ast/walk.go:355 +0x15c5 go/ast.Inspect(...) /usr/local/go/src/go/ast/walk.go:387 github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).convertGlobals(0xc0001623c0, 0xc000156c80, 0xc000254280) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:354 +0x71 github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).traverseGlobals.func2(0xc000254280) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/analysis.go:86 +0x16e github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).ForEachPackage(0xc0001623c0, 0xc000191b98) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/compiler.go:93 +0xc6 github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).traverseGlobals(0xc0001623c0) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/analysis.go:82 +0x22c github.com/nspcc-dev/neo-go/pkg/compiler.(*codegen).compile(0xc0001623c0, 0xc000274d20, 0x1) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:2118 +0x17c github.com/nspcc-dev/neo-go/pkg/compiler.codeGen(0xc000274d20) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/codegen.go:2191 +0x353 github.com/nspcc-dev/neo-go/pkg/compiler.CompileWithOptions({0xa6f39a, 0xc00023cee0}, {0xc6d240, 0xc00024a460}, 0x0) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/compiler.go:218 +0x65 github.com/nspcc-dev/neo-go/pkg/compiler_test.vmAndCompileInterop(0x5648df, {0xa9989f, 0x7d}) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/vm_test.go:75 +0x113 github.com/nspcc-dev/neo-go/pkg/compiler_test.eval(0xc00024a440, {0xa9989f, 0x129f366e}, {0xa68880, 0xc00024a440}) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/vm_test.go:36 +0x2d github.com/nspcc-dev/neo-go/pkg/compiler_test.TestGenDeclWithMultiRet.func2(0x4079f9) /home/anna/Documents/GitProjects/nspcc-dev/neo-go/pkg/compiler/global_test.go:36 +0x4f testing.tRunner(0xc00022e9c0, 0xbce760) /usr/local/go/src/testing/testing.go:1259 +0x102 created by testing.(*T).Run /usr/local/go/src/testing/testing.go:1306 +0x35a ``` Solution: Allow using multi-return function calls as general variable declaration value. It was supported for assignment statements, so do the same for *ast.GenDecl if it's a variable under the hood.	2022-08-16 15:33:44 +03:00