From b440c15db71ba0ac0b995428a52b380814882627 Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Thu, 6 Oct 2022 13:51:52 -0700 Subject: [PATCH] internal/types/errors: add package The internal/types/errors package defines all error codes used by the type checkers. This is the 1st step of several that factor out the error codes from go/types and types2; the package is not yet used. - The file codes.go is a copy of go/types/errorcodes.go. The only change is the updated package name (types -> errors). - The file codes_test.go is a copy of go/types/errorcodes_test.go with updated package name (types_test -> errors_test) and minor changes to walkCodes so that it doesn't require the pkgFiles helper function (the test only parses a single file). Change-Id: Idb977b1220737b56b330de1d977f698f022daafc Reviewed-on: https://go-review.googlesource.com/c/go/+/439560 Run-TryBot: Robert Griesemer Auto-Submit: Robert Griesemer Reviewed-by: Robert Findley TryBot-Result: Gopher Robot Reviewed-by: Robert Griesemer --- src/internal/types/errors/codes.go | 1423 +++++++++++++++++++++++ src/internal/types/errors/codes_test.go | 197 ++++ 2 files changed, 1620 insertions(+) create mode 100644 src/internal/types/errors/codes.go create mode 100644 src/internal/types/errors/codes_test.go diff --git a/src/internal/types/errors/codes.go b/src/internal/types/errors/codes.go new file mode 100644 index 0000000000..3546c65243 --- /dev/null +++ b/src/internal/types/errors/codes.go @@ -0,0 +1,1423 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package errors + +type errorCode int + +// This file defines the error codes that can be produced during type-checking. +// Collectively, these codes provide an identifier that may be used to +// implement special handling for certain types of errors. +// +// Error code values should not be changed: add new codes at the end. +// +// Error codes should be fine-grained enough that the exact nature of the error +// can be easily determined, but coarse enough that they are not an +// implementation detail of the type checking algorithm. As a rule-of-thumb, +// errors should be considered equivalent if there is a theoretical refactoring +// of the type checker in which they are emitted in exactly one place. For +// example, the type checker emits different error messages for "too many +// arguments" and "too few arguments", but one can imagine an alternative type +// checker where this check instead just emits a single "wrong number of +// arguments", so these errors should have the same code. +// +// Error code names should be as brief as possible while retaining accuracy and +// distinctiveness. In most cases names should start with an adjective +// describing the nature of the error (e.g. "invalid", "unused", "misplaced"), +// and end with a noun identifying the relevant language object. For example, +// "_DuplicateDecl" or "_InvalidSliceExpr". For brevity, naming follows the +// convention that "bad" implies a problem with syntax, and "invalid" implies a +// problem with types. + +const ( + _ errorCode = iota + + // _Test is reserved for errors that only apply while in self-test mode. + _Test + + // _BlankPkgName occurs when a package name is the blank identifier "_". + // + // Per the spec: + // "The PackageName must not be the blank identifier." + _BlankPkgName + + // _MismatchedPkgName occurs when a file's package name doesn't match the + // package name already established by other files. + _MismatchedPkgName + + // _InvalidPkgUse occurs when a package identifier is used outside of a + // selector expression. + // + // Example: + // import "fmt" + // + // var _ = fmt + _InvalidPkgUse + + // _BadImportPath occurs when an import path is not valid. + _BadImportPath + + // _BrokenImport occurs when importing a package fails. + // + // Example: + // import "amissingpackage" + _BrokenImport + + // _ImportCRenamed occurs when the special import "C" is renamed. "C" is a + // pseudo-package, and must not be renamed. + // + // Example: + // import _ "C" + _ImportCRenamed + + // _UnusedImport occurs when an import is unused. + // + // Example: + // import "fmt" + // + // func main() {} + _UnusedImport + + // _InvalidInitCycle occurs when an invalid cycle is detected within the + // initialization graph. + // + // Example: + // var x int = f() + // + // func f() int { return x } + _InvalidInitCycle + + // _DuplicateDecl occurs when an identifier is declared multiple times. + // + // Example: + // var x = 1 + // var x = 2 + _DuplicateDecl + + // _InvalidDeclCycle occurs when a declaration cycle is not valid. + // + // Example: + // type S struct { + // S + // } + // + _InvalidDeclCycle + + // _InvalidTypeCycle occurs when a cycle in type definitions results in a + // type that is not well-defined. + // + // Example: + // import "unsafe" + // + // type T [unsafe.Sizeof(T{})]int + _InvalidTypeCycle + + // _InvalidConstInit occurs when a const declaration has a non-constant + // initializer. + // + // Example: + // var x int + // const _ = x + _InvalidConstInit + + // _InvalidConstVal occurs when a const value cannot be converted to its + // target type. + // + // TODO(findleyr): this error code and example are not very clear. Consider + // removing it. + // + // Example: + // const _ = 1 << "hello" + _InvalidConstVal + + // _InvalidConstType occurs when the underlying type in a const declaration + // is not a valid constant type. + // + // Example: + // const c *int = 4 + _InvalidConstType + + // _UntypedNil occurs when the predeclared (untyped) value nil is used to + // initialize a variable declared without an explicit type. + // + // Example: + // var x = nil + _UntypedNil + + // _WrongAssignCount occurs when the number of values on the right-hand side + // of an assignment or initialization expression does not match the number + // of variables on the left-hand side. + // + // Example: + // var x = 1, 2 + _WrongAssignCount + + // _UnassignableOperand occurs when the left-hand side of an assignment is + // not assignable. + // + // Example: + // func f() { + // const c = 1 + // c = 2 + // } + _UnassignableOperand + + // _NoNewVar occurs when a short variable declaration (':=') does not declare + // new variables. + // + // Example: + // func f() { + // x := 1 + // x := 2 + // } + _NoNewVar + + // _MultiValAssignOp occurs when an assignment operation (+=, *=, etc) does + // not have single-valued left-hand or right-hand side. + // + // Per the spec: + // "In assignment operations, both the left- and right-hand expression lists + // must contain exactly one single-valued expression" + // + // Example: + // func f() int { + // x, y := 1, 2 + // x, y += 1 + // return x + y + // } + _MultiValAssignOp + + // _InvalidIfaceAssign occurs when a value of type T is used as an + // interface, but T does not implement a method of the expected interface. + // + // Example: + // type I interface { + // f() + // } + // + // type T int + // + // var x I = T(1) + _InvalidIfaceAssign + + // _InvalidChanAssign occurs when a chan assignment is invalid. + // + // Per the spec, a value x is assignable to a channel type T if: + // "x is a bidirectional channel value, T is a channel type, x's type V and + // T have identical element types, and at least one of V or T is not a + // defined type." + // + // Example: + // type T1 chan int + // type T2 chan int + // + // var x T1 + // // Invalid assignment because both types are named + // var _ T2 = x + _InvalidChanAssign + + // _IncompatibleAssign occurs when the type of the right-hand side expression + // in an assignment cannot be assigned to the type of the variable being + // assigned. + // + // Example: + // var x []int + // var _ int = x + _IncompatibleAssign + + // _UnaddressableFieldAssign occurs when trying to assign to a struct field + // in a map value. + // + // Example: + // func f() { + // m := make(map[string]struct{i int}) + // m["foo"].i = 42 + // } + _UnaddressableFieldAssign + + // _NotAType occurs when the identifier used as the underlying type in a type + // declaration or the right-hand side of a type alias does not denote a type. + // + // Example: + // var S = 2 + // + // type T S + _NotAType + + // _InvalidArrayLen occurs when an array length is not a constant value. + // + // Example: + // var n = 3 + // var _ = [n]int{} + _InvalidArrayLen + + // _BlankIfaceMethod occurs when a method name is '_'. + // + // Per the spec: + // "The name of each explicitly specified method must be unique and not + // blank." + // + // Example: + // type T interface { + // _(int) + // } + _BlankIfaceMethod + + // _IncomparableMapKey occurs when a map key type does not support the == and + // != operators. + // + // Per the spec: + // "The comparison operators == and != must be fully defined for operands of + // the key type; thus the key type must not be a function, map, or slice." + // + // Example: + // var x map[T]int + // + // type T []int + _IncomparableMapKey + + // _InvalidIfaceEmbed occurs when a non-interface type is embedded in an + // interface (for go 1.17 or earlier). + _ // not used anymore + + // _InvalidPtrEmbed occurs when an embedded field is of the pointer form *T, + // and T itself is itself a pointer, an unsafe.Pointer, or an interface. + // + // Per the spec: + // "An embedded field must be specified as a type name T or as a pointer to + // a non-interface type name *T, and T itself may not be a pointer type." + // + // Example: + // type T *int + // + // type S struct { + // *T + // } + _InvalidPtrEmbed + + // _BadRecv occurs when a method declaration does not have exactly one + // receiver parameter. + // + // Example: + // func () _() {} + _BadRecv + + // _InvalidRecv occurs when a receiver type expression is not of the form T + // or *T, or T is a pointer type. + // + // Example: + // type T struct {} + // + // func (**T) m() {} + _InvalidRecv + + // _DuplicateFieldAndMethod occurs when an identifier appears as both a field + // and method name. + // + // Example: + // type T struct { + // m int + // } + // + // func (T) m() {} + _DuplicateFieldAndMethod + + // _DuplicateMethod occurs when two methods on the same receiver type have + // the same name. + // + // Example: + // type T struct {} + // func (T) m() {} + // func (T) m(i int) int { return i } + _DuplicateMethod + + // _InvalidBlank occurs when a blank identifier is used as a value or type. + // + // Per the spec: + // "The blank identifier may appear as an operand only on the left-hand side + // of an assignment." + // + // Example: + // var x = _ + _InvalidBlank + + // _InvalidIota occurs when the predeclared identifier iota is used outside + // of a constant declaration. + // + // Example: + // var x = iota + _InvalidIota + + // _MissingInitBody occurs when an init function is missing its body. + // + // Example: + // func init() + _MissingInitBody + + // _InvalidInitSig occurs when an init function declares parameters or + // results. + // + // Deprecated: no longer emitted by the type checker. _InvalidInitDecl is + // used instead. + _InvalidInitSig + + // _InvalidInitDecl occurs when init is declared as anything other than a + // function. + // + // Example: + // var init = 1 + // + // Example: + // func init() int { return 1 } + _InvalidInitDecl + + // _InvalidMainDecl occurs when main is declared as anything other than a + // function, in a main package. + _InvalidMainDecl + + // _TooManyValues occurs when a function returns too many values for the + // expression context in which it is used. + // + // Example: + // func ReturnTwo() (int, int) { + // return 1, 2 + // } + // + // var x = ReturnTwo() + _TooManyValues + + // _NotAnExpr occurs when a type expression is used where a value expression + // is expected. + // + // Example: + // type T struct {} + // + // func f() { + // T + // } + _NotAnExpr + + // _TruncatedFloat occurs when a float constant is truncated to an integer + // value. + // + // Example: + // var _ int = 98.6 + _TruncatedFloat + + // _NumericOverflow occurs when a numeric constant overflows its target type. + // + // Example: + // var x int8 = 1000 + _NumericOverflow + + // _UndefinedOp occurs when an operator is not defined for the type(s) used + // in an operation. + // + // Example: + // var c = "a" - "b" + _UndefinedOp + + // _MismatchedTypes occurs when operand types are incompatible in a binary + // operation. + // + // Example: + // var a = "hello" + // var b = 1 + // var c = a - b + _MismatchedTypes + + // _DivByZero occurs when a division operation is provable at compile + // time to be a division by zero. + // + // Example: + // const divisor = 0 + // var x int = 1/divisor + _DivByZero + + // _NonNumericIncDec occurs when an increment or decrement operator is + // applied to a non-numeric value. + // + // Example: + // func f() { + // var c = "c" + // c++ + // } + _NonNumericIncDec + + // _UnaddressableOperand occurs when the & operator is applied to an + // unaddressable expression. + // + // Example: + // var x = &1 + _UnaddressableOperand + + // _InvalidIndirection occurs when a non-pointer value is indirected via the + // '*' operator. + // + // Example: + // var x int + // var y = *x + _InvalidIndirection + + // _NonIndexableOperand occurs when an index operation is applied to a value + // that cannot be indexed. + // + // Example: + // var x = 1 + // var y = x[1] + _NonIndexableOperand + + // _InvalidIndex occurs when an index argument is not of integer type, + // negative, or out-of-bounds. + // + // Example: + // var s = [...]int{1,2,3} + // var x = s[5] + // + // Example: + // var s = []int{1,2,3} + // var _ = s[-1] + // + // Example: + // var s = []int{1,2,3} + // var i string + // var _ = s[i] + _InvalidIndex + + // _SwappedSliceIndices occurs when constant indices in a slice expression + // are decreasing in value. + // + // Example: + // var _ = []int{1,2,3}[2:1] + _SwappedSliceIndices + + // _NonSliceableOperand occurs when a slice operation is applied to a value + // whose type is not sliceable, or is unaddressable. + // + // Example: + // var x = [...]int{1, 2, 3}[:1] + // + // Example: + // var x = 1 + // var y = 1[:1] + _NonSliceableOperand + + // _InvalidSliceExpr occurs when a three-index slice expression (a[x:y:z]) is + // applied to a string. + // + // Example: + // var s = "hello" + // var x = s[1:2:3] + _InvalidSliceExpr + + // _InvalidShiftCount occurs when the right-hand side of a shift operation is + // either non-integer, negative, or too large. + // + // Example: + // var ( + // x string + // y int = 1 << x + // ) + _InvalidShiftCount + + // _InvalidShiftOperand occurs when the shifted operand is not an integer. + // + // Example: + // var s = "hello" + // var x = s << 2 + _InvalidShiftOperand + + // _InvalidReceive occurs when there is a channel receive from a value that + // is either not a channel, or is a send-only channel. + // + // Example: + // func f() { + // var x = 1 + // <-x + // } + _InvalidReceive + + // _InvalidSend occurs when there is a channel send to a value that is not a + // channel, or is a receive-only channel. + // + // Example: + // func f() { + // var x = 1 + // x <- "hello!" + // } + _InvalidSend + + // _DuplicateLitKey occurs when an index is duplicated in a slice, array, or + // map literal. + // + // Example: + // var _ = []int{0:1, 0:2} + // + // Example: + // var _ = map[string]int{"a": 1, "a": 2} + _DuplicateLitKey + + // _MissingLitKey occurs when a map literal is missing a key expression. + // + // Example: + // var _ = map[string]int{1} + _MissingLitKey + + // _InvalidLitIndex occurs when the key in a key-value element of a slice or + // array literal is not an integer constant. + // + // Example: + // var i = 0 + // var x = []string{i: "world"} + _InvalidLitIndex + + // _OversizeArrayLit occurs when an array literal exceeds its length. + // + // Example: + // var _ = [2]int{1,2,3} + _OversizeArrayLit + + // _MixedStructLit occurs when a struct literal contains a mix of positional + // and named elements. + // + // Example: + // var _ = struct{i, j int}{i: 1, 2} + _MixedStructLit + + // _InvalidStructLit occurs when a positional struct literal has an incorrect + // number of values. + // + // Example: + // var _ = struct{i, j int}{1,2,3} + _InvalidStructLit + + // _MissingLitField occurs when a struct literal refers to a field that does + // not exist on the struct type. + // + // Example: + // var _ = struct{i int}{j: 2} + _MissingLitField + + // _DuplicateLitField occurs when a struct literal contains duplicated + // fields. + // + // Example: + // var _ = struct{i int}{i: 1, i: 2} + _DuplicateLitField + + // _UnexportedLitField occurs when a positional struct literal implicitly + // assigns an unexported field of an imported type. + _UnexportedLitField + + // _InvalidLitField occurs when a field name is not a valid identifier. + // + // Example: + // var _ = struct{i int}{1: 1} + _InvalidLitField + + // _UntypedLit occurs when a composite literal omits a required type + // identifier. + // + // Example: + // type outer struct{ + // inner struct { i int } + // } + // + // var _ = outer{inner: {1}} + _UntypedLit + + // _InvalidLit occurs when a composite literal expression does not match its + // type. + // + // Example: + // type P *struct{ + // x int + // } + // var _ = P {} + _InvalidLit + + // _AmbiguousSelector occurs when a selector is ambiguous. + // + // Example: + // type E1 struct { i int } + // type E2 struct { i int } + // type T struct { E1; E2 } + // + // var x T + // var _ = x.i + _AmbiguousSelector + + // _UndeclaredImportedName occurs when a package-qualified identifier is + // undeclared by the imported package. + // + // Example: + // import "go/types" + // + // var _ = types.NotAnActualIdentifier + _UndeclaredImportedName + + // _UnexportedName occurs when a selector refers to an unexported identifier + // of an imported package. + // + // Example: + // import "reflect" + // + // type _ reflect.flag + _UnexportedName + + // _UndeclaredName occurs when an identifier is not declared in the current + // scope. + // + // Example: + // var x T + _UndeclaredName + + // _MissingFieldOrMethod occurs when a selector references a field or method + // that does not exist. + // + // Example: + // type T struct {} + // + // var x = T{}.f + _MissingFieldOrMethod + + // _BadDotDotDotSyntax occurs when a "..." occurs in a context where it is + // not valid. + // + // Example: + // var _ = map[int][...]int{0: {}} + _BadDotDotDotSyntax + + // _NonVariadicDotDotDot occurs when a "..." is used on the final argument to + // a non-variadic function. + // + // Example: + // func printArgs(s []string) { + // for _, a := range s { + // println(a) + // } + // } + // + // func f() { + // s := []string{"a", "b", "c"} + // printArgs(s...) + // } + _NonVariadicDotDotDot + + // _MisplacedDotDotDot occurs when a "..." is used somewhere other than the + // final argument in a function declaration. + // + // Example: + // func f(...int, int) + _MisplacedDotDotDot + + _ // _InvalidDotDotDotOperand was removed. + + // _InvalidDotDotDot occurs when a "..." is used in a non-variadic built-in + // function. + // + // Example: + // var s = []int{1, 2, 3} + // var l = len(s...) + _InvalidDotDotDot + + // _UncalledBuiltin occurs when a built-in function is used as a + // function-valued expression, instead of being called. + // + // Per the spec: + // "The built-in functions do not have standard Go types, so they can only + // appear in call expressions; they cannot be used as function values." + // + // Example: + // var _ = copy + _UncalledBuiltin + + // _InvalidAppend occurs when append is called with a first argument that is + // not a slice. + // + // Example: + // var _ = append(1, 2) + _InvalidAppend + + // _InvalidCap occurs when an argument to the cap built-in function is not of + // supported type. + // + // See https://golang.org/ref/spec#Length_and_capacity for information on + // which underlying types are supported as arguments to cap and len. + // + // Example: + // var s = 2 + // var x = cap(s) + _InvalidCap + + // _InvalidClose occurs when close(...) is called with an argument that is + // not of channel type, or that is a receive-only channel. + // + // Example: + // func f() { + // var x int + // close(x) + // } + _InvalidClose + + // _InvalidCopy occurs when the arguments are not of slice type or do not + // have compatible type. + // + // See https://golang.org/ref/spec#Appending_and_copying_slices for more + // information on the type requirements for the copy built-in. + // + // Example: + // func f() { + // var x []int + // y := []int64{1,2,3} + // copy(x, y) + // } + _InvalidCopy + + // _InvalidComplex occurs when the complex built-in function is called with + // arguments with incompatible types. + // + // Example: + // var _ = complex(float32(1), float64(2)) + _InvalidComplex + + // _InvalidDelete occurs when the delete built-in function is called with a + // first argument that is not a map. + // + // Example: + // func f() { + // m := "hello" + // delete(m, "e") + // } + _InvalidDelete + + // _InvalidImag occurs when the imag built-in function is called with an + // argument that does not have complex type. + // + // Example: + // var _ = imag(int(1)) + _InvalidImag + + // _InvalidLen occurs when an argument to the len built-in function is not of + // supported type. + // + // See https://golang.org/ref/spec#Length_and_capacity for information on + // which underlying types are supported as arguments to cap and len. + // + // Example: + // var s = 2 + // var x = len(s) + _InvalidLen + + // _SwappedMakeArgs occurs when make is called with three arguments, and its + // length argument is larger than its capacity argument. + // + // Example: + // var x = make([]int, 3, 2) + _SwappedMakeArgs + + // _InvalidMake occurs when make is called with an unsupported type argument. + // + // See https://golang.org/ref/spec#Making_slices_maps_and_channels for + // information on the types that may be created using make. + // + // Example: + // var x = make(int) + _InvalidMake + + // _InvalidReal occurs when the real built-in function is called with an + // argument that does not have complex type. + // + // Example: + // var _ = real(int(1)) + _InvalidReal + + // _InvalidAssert occurs when a type assertion is applied to a + // value that is not of interface type. + // + // Example: + // var x = 1 + // var _ = x.(float64) + _InvalidAssert + + // _ImpossibleAssert occurs for a type assertion x.(T) when the value x of + // interface cannot have dynamic type T, due to a missing or mismatching + // method on T. + // + // Example: + // type T int + // + // func (t *T) m() int { return int(*t) } + // + // type I interface { m() int } + // + // var x I + // var _ = x.(T) + _ImpossibleAssert + + // _InvalidConversion occurs when the argument type cannot be converted to the + // target. + // + // See https://golang.org/ref/spec#Conversions for the rules of + // convertibility. + // + // Example: + // var x float64 + // var _ = string(x) + _InvalidConversion + + // _InvalidUntypedConversion occurs when there is no valid implicit + // conversion from an untyped value satisfying the type constraints of the + // context in which it is used. + // + // Example: + // var _ = 1 + new(int) + _InvalidUntypedConversion + + // _BadOffsetofSyntax occurs when unsafe.Offsetof is called with an argument + // that is not a selector expression. + // + // Example: + // import "unsafe" + // + // var x int + // var _ = unsafe.Offsetof(x) + _BadOffsetofSyntax + + // _InvalidOffsetof occurs when unsafe.Offsetof is called with a method + // selector, rather than a field selector, or when the field is embedded via + // a pointer. + // + // Per the spec: + // + // "If f is an embedded field, it must be reachable without pointer + // indirections through fields of the struct. " + // + // Example: + // import "unsafe" + // + // type T struct { f int } + // type S struct { *T } + // var s S + // var _ = unsafe.Offsetof(s.f) + // + // Example: + // import "unsafe" + // + // type S struct{} + // + // func (S) m() {} + // + // var s S + // var _ = unsafe.Offsetof(s.m) + _InvalidOffsetof + + // _UnusedExpr occurs when a side-effect free expression is used as a + // statement. Such a statement has no effect. + // + // Example: + // func f(i int) { + // i*i + // } + _UnusedExpr + + // _UnusedVar occurs when a variable is declared but unused. + // + // Example: + // func f() { + // x := 1 + // } + _UnusedVar + + // _MissingReturn occurs when a function with results is missing a return + // statement. + // + // Example: + // func f() int {} + _MissingReturn + + // _WrongResultCount occurs when a return statement returns an incorrect + // number of values. + // + // Example: + // func ReturnOne() int { + // return 1, 2 + // } + _WrongResultCount + + // _OutOfScopeResult occurs when the name of a value implicitly returned by + // an empty return statement is shadowed in a nested scope. + // + // Example: + // func factor(n int) (i int) { + // for i := 2; i < n; i++ { + // if n%i == 0 { + // return + // } + // } + // return 0 + // } + _OutOfScopeResult + + // _InvalidCond occurs when an if condition is not a boolean expression. + // + // Example: + // func checkReturn(i int) { + // if i { + // panic("non-zero return") + // } + // } + _InvalidCond + + // _InvalidPostDecl occurs when there is a declaration in a for-loop post + // statement. + // + // Example: + // func f() { + // for i := 0; i < 10; j := 0 {} + // } + _InvalidPostDecl + + _ // _InvalidChanRange was removed. + + // _InvalidIterVar occurs when two iteration variables are used while ranging + // over a channel. + // + // Example: + // func f(c chan int) { + // for k, v := range c { + // println(k, v) + // } + // } + _InvalidIterVar + + // _InvalidRangeExpr occurs when the type of a range expression is not array, + // slice, string, map, or channel. + // + // Example: + // func f(i int) { + // for j := range i { + // println(j) + // } + // } + _InvalidRangeExpr + + // _MisplacedBreak occurs when a break statement is not within a for, switch, + // or select statement of the innermost function definition. + // + // Example: + // func f() { + // break + // } + _MisplacedBreak + + // _MisplacedContinue occurs when a continue statement is not within a for + // loop of the innermost function definition. + // + // Example: + // func sumeven(n int) int { + // proceed := func() { + // continue + // } + // sum := 0 + // for i := 1; i <= n; i++ { + // if i % 2 != 0 { + // proceed() + // } + // sum += i + // } + // return sum + // } + _MisplacedContinue + + // _MisplacedFallthrough occurs when a fallthrough statement is not within an + // expression switch. + // + // Example: + // func typename(i interface{}) string { + // switch i.(type) { + // case int64: + // fallthrough + // case int: + // return "int" + // } + // return "unsupported" + // } + _MisplacedFallthrough + + // _DuplicateCase occurs when a type or expression switch has duplicate + // cases. + // + // Example: + // func printInt(i int) { + // switch i { + // case 1: + // println("one") + // case 1: + // println("One") + // } + // } + _DuplicateCase + + // _DuplicateDefault occurs when a type or expression switch has multiple + // default clauses. + // + // Example: + // func printInt(i int) { + // switch i { + // case 1: + // println("one") + // default: + // println("One") + // default: + // println("1") + // } + // } + _DuplicateDefault + + // _BadTypeKeyword occurs when a .(type) expression is used anywhere other + // than a type switch. + // + // Example: + // type I interface { + // m() + // } + // var t I + // var _ = t.(type) + _BadTypeKeyword + + // _InvalidTypeSwitch occurs when .(type) is used on an expression that is + // not of interface type. + // + // Example: + // func f(i int) { + // switch x := i.(type) {} + // } + _InvalidTypeSwitch + + // _InvalidExprSwitch occurs when a switch expression is not comparable. + // + // Example: + // func _() { + // var a struct{ _ func() } + // switch a /* ERROR cannot switch on a */ { + // } + // } + _InvalidExprSwitch + + // _InvalidSelectCase occurs when a select case is not a channel send or + // receive. + // + // Example: + // func checkChan(c <-chan int) bool { + // select { + // case c: + // return true + // default: + // return false + // } + // } + _InvalidSelectCase + + // _UndeclaredLabel occurs when an undeclared label is jumped to. + // + // Example: + // func f() { + // goto L + // } + _UndeclaredLabel + + // _DuplicateLabel occurs when a label is declared more than once. + // + // Example: + // func f() int { + // L: + // L: + // return 1 + // } + _DuplicateLabel + + // _MisplacedLabel occurs when a break or continue label is not on a for, + // switch, or select statement. + // + // Example: + // func f() { + // L: + // a := []int{1,2,3} + // for _, e := range a { + // if e > 10 { + // break L + // } + // println(a) + // } + // } + _MisplacedLabel + + // _UnusedLabel occurs when a label is declared and not used. + // + // Example: + // func f() { + // L: + // } + _UnusedLabel + + // _JumpOverDecl occurs when a label jumps over a variable declaration. + // + // Example: + // func f() int { + // goto L + // x := 2 + // L: + // x++ + // return x + // } + _JumpOverDecl + + // _JumpIntoBlock occurs when a forward jump goes to a label inside a nested + // block. + // + // Example: + // func f(x int) { + // goto L + // if x > 0 { + // L: + // print("inside block") + // } + // } + _JumpIntoBlock + + // _InvalidMethodExpr occurs when a pointer method is called but the argument + // is not addressable. + // + // Example: + // type T struct {} + // + // func (*T) m() int { return 1 } + // + // var _ = T.m(T{}) + _InvalidMethodExpr + + // _WrongArgCount occurs when too few or too many arguments are passed by a + // function call. + // + // Example: + // func f(i int) {} + // var x = f() + _WrongArgCount + + // _InvalidCall occurs when an expression is called that is not of function + // type. + // + // Example: + // var x = "x" + // var y = x() + _InvalidCall + + // _UnusedResults occurs when a restricted expression-only built-in function + // is suspended via go or defer. Such a suspension discards the results of + // these side-effect free built-in functions, and therefore is ineffectual. + // + // Example: + // func f(a []int) int { + // defer len(a) + // return i + // } + _UnusedResults + + // _InvalidDefer occurs when a deferred expression is not a function call, + // for example if the expression is a type conversion. + // + // Example: + // func f(i int) int { + // defer int32(i) + // return i + // } + _InvalidDefer + + // _InvalidGo occurs when a go expression is not a function call, for example + // if the expression is a type conversion. + // + // Example: + // func f(i int) int { + // go int32(i) + // return i + // } + _InvalidGo + + // All codes below were added in Go 1.17. + + // _BadDecl occurs when a declaration has invalid syntax. + _BadDecl + + // _RepeatedDecl occurs when an identifier occurs more than once on the left + // hand side of a short variable declaration. + // + // Example: + // func _() { + // x, y, y := 1, 2, 3 + // } + _RepeatedDecl + + // _InvalidUnsafeAdd occurs when unsafe.Add is called with a + // length argument that is not of integer type. + // It also occurs if it is used in a package compiled for a + // language version before go1.17. + // + // Example: + // import "unsafe" + // + // var p unsafe.Pointer + // var _ = unsafe.Add(p, float64(1)) + _InvalidUnsafeAdd + + // _InvalidUnsafeSlice occurs when unsafe.Slice is called with a + // pointer argument that is not of pointer type or a length argument + // that is not of integer type, negative, or out of bounds. + // It also occurs if it is used in a package compiled for a language + // version before go1.17. + // + // Example: + // import "unsafe" + // + // var x int + // var _ = unsafe.Slice(x, 1) + // + // Example: + // import "unsafe" + // + // var x int + // var _ = unsafe.Slice(&x, float64(1)) + // + // Example: + // import "unsafe" + // + // var x int + // var _ = unsafe.Slice(&x, -1) + // + // Example: + // import "unsafe" + // + // var x int + // var _ = unsafe.Slice(&x, uint64(1) << 63) + _InvalidUnsafeSlice + + // All codes below were added in Go 1.18. + + // _UnsupportedFeature occurs when a language feature is used that is not + // supported at this Go version. + _UnsupportedFeature + + // _NotAGenericType occurs when a non-generic type is used where a generic + // type is expected: in type or function instantiation. + // + // Example: + // type T int + // + // var _ T[int] + _NotAGenericType + + // _WrongTypeArgCount occurs when a type or function is instantiated with an + // incorrent number of type arguments, including when a generic type or + // function is used without instantiation. + // + // Errors inolving failed type inference are assigned other error codes. + // + // Example: + // type T[p any] int + // + // var _ T[int, string] + // + // Example: + // func f[T any]() {} + // + // var x = f + _WrongTypeArgCount + + // _CannotInferTypeArgs occurs when type or function type argument inference + // fails to infer all type arguments. + // + // Example: + // func f[T any]() {} + // + // func _() { + // f() + // } + _CannotInferTypeArgs + + // _InvalidTypeArg occurs when a type argument does not satisfy its + // corresponding type parameter constraints. + // + // Example: + // type T[P ~int] struct{} + // + // var _ T[string] + _InvalidTypeArg // arguments? InferenceFailed + + // _InvalidInstanceCycle occurs when an invalid cycle is detected + // within the instantiation graph. + // + // Example: + // func f[T any]() { f[*T]() } + _InvalidInstanceCycle + + // _InvalidUnion occurs when an embedded union or approximation element is + // not valid. + // + // Example: + // type _ interface { + // ~int | interface{ m() } + // } + _InvalidUnion + + // _MisplacedConstraintIface occurs when a constraint-type interface is used + // outside of constraint position. + // + // Example: + // type I interface { ~int } + // + // var _ I + _MisplacedConstraintIface + + // _InvalidMethodTypeParams occurs when methods have type parameters. + // + // It cannot be encountered with an AST parsed using go/parser. + _InvalidMethodTypeParams + + // _MisplacedTypeParam occurs when a type parameter is used in a place where + // it is not permitted. + // + // Example: + // type T[P any] P + // + // Example: + // type T[P any] struct{ *P } + _MisplacedTypeParam + + // _InvalidUnsafeSliceData occurs when unsafe.SliceData is called with + // an argument that is not of slice type. It also occurs if it is used + // in a package compiled for a language version before go1.20. + // + // Example: + // import "unsafe" + // + // var x int + // var _ = unsafe.SliceData(x) + _InvalidUnsafeSliceData + + // _InvalidUnsafeString occurs when unsafe.String is called with + // a length argument that is not of integer type, negative, or + // out of bounds. It also occurs if it is used in a package + // compiled for a language version before go1.20. + // + // Example: + // import "unsafe" + // + // var b [10]byte + // var _ = unsafe.String(&b[0], -1) + _InvalidUnsafeString + + // _InvalidUnsafeStringData occurs if it is used in a package + // compiled for a language version before go1.20. + _ // not used anymore +) diff --git a/src/internal/types/errors/codes_test.go b/src/internal/types/errors/codes_test.go new file mode 100644 index 0000000000..37a4aa6ae8 --- /dev/null +++ b/src/internal/types/errors/codes_test.go @@ -0,0 +1,197 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package errors_test + +import ( + "fmt" + "go/ast" + "go/constant" + "go/importer" + "go/parser" + "go/token" + "reflect" + "strings" + "testing" + + . "go/types" +) + +func TestErrorCodeExamples(t *testing.T) { + walkCodes(t, func(name string, value int, spec *ast.ValueSpec) { + t.Run(name, func(t *testing.T) { + doc := spec.Doc.Text() + examples := strings.Split(doc, "Example:") + for i := 1; i < len(examples); i++ { + example := examples[i] + err := checkExample(t, example) + if err == nil { + t.Fatalf("no error in example #%d", i) + } + typerr, ok := err.(Error) + if !ok { + t.Fatalf("not a types.Error: %v", err) + } + if got := readCode(typerr); got != value { + t.Errorf("%s: example #%d returned code %d (%s), want %d", name, i, got, err, value) + } + } + }) + }) +} + +func walkCodes(t *testing.T, f func(string, int, *ast.ValueSpec)) { + t.Helper() + fset := token.NewFileSet() + file, err := parser.ParseFile(fset, "codes.go", nil, parser.ParseComments) + if err != nil { + t.Fatal(err) + } + conf := Config{Importer: importer.Default()} + info := &Info{ + Types: make(map[ast.Expr]TypeAndValue), + Defs: make(map[*ast.Ident]Object), + Uses: make(map[*ast.Ident]Object), + } + _, err = conf.Check("types", fset, []*ast.File{file}, info) + if err != nil { + t.Fatal(err) + } + for _, decl := range file.Decls { + decl, ok := decl.(*ast.GenDecl) + if !ok || decl.Tok != token.CONST { + continue + } + for _, spec := range decl.Specs { + spec, ok := spec.(*ast.ValueSpec) + if !ok || len(spec.Names) == 0 { + continue + } + obj := info.ObjectOf(spec.Names[0]) + if named, ok := obj.Type().(*Named); ok && named.Obj().Name() == "errorCode" { + if len(spec.Names) != 1 { + t.Fatalf("bad Code declaration for %q: got %d names, want exactly 1", spec.Names[0].Name, len(spec.Names)) + } + codename := spec.Names[0].Name + value := int(constant.Val(obj.(*Const).Val()).(int64)) + f(codename, value, spec) + } + } + } +} + +func readCode(err Error) int { + v := reflect.ValueOf(err) + return int(v.FieldByName("go116code").Int()) +} + +func checkExample(t *testing.T, example string) error { + t.Helper() + fset := token.NewFileSet() + src := fmt.Sprintf("package p\n\n%s", example) + file, err := parser.ParseFile(fset, "example.go", src, 0) + if err != nil { + t.Fatal(err) + } + conf := Config{ + FakeImportC: true, + Importer: importer.Default(), + } + _, err = conf.Check("example", fset, []*ast.File{file}, nil) + return err +} + +func TestErrorCodeStyle(t *testing.T) { + // The set of error codes is large and intended to be self-documenting, so + // this test enforces some style conventions. + forbiddenInIdent := []string{ + // use invalid instead + "illegal", + // words with a common short-form + "argument", + "assertion", + "assignment", + "boolean", + "channel", + "condition", + "declaration", + "expression", + "function", + "initial", // use init for initializer, initialization, etc. + "integer", + "interface", + "iterat", // use iter for iterator, iteration, etc. + "literal", + "operation", + "package", + "pointer", + "receiver", + "signature", + "statement", + "variable", + } + forbiddenInComment := []string{ + // lhs and rhs should be spelled-out. + "lhs", "rhs", + // builtin should be hyphenated. + "builtin", + // Use dot-dot-dot. + "ellipsis", + } + nameHist := make(map[int]int) + longestName := "" + maxValue := 0 + + walkCodes(t, func(name string, value int, spec *ast.ValueSpec) { + if name == "_" { + return + } + nameHist[len(name)]++ + if value > maxValue { + maxValue = value + } + if len(name) > len(longestName) { + longestName = name + } + if token.IsExported(name) { + // This is an experimental API, and errorCode values should not be + // exported. + t.Errorf("%q is exported", name) + } + if name[0] != '_' || !token.IsExported(name[1:]) { + t.Errorf("%q should start with _, followed by an exported identifier", name) + } + lower := strings.ToLower(name) + for _, bad := range forbiddenInIdent { + if strings.Contains(lower, bad) { + t.Errorf("%q contains forbidden word %q", name, bad) + } + } + doc := spec.Doc.Text() + if doc == "" { + t.Errorf("%q is undocumented", name) + } else if !strings.HasPrefix(doc, name) { + t.Errorf("doc for %q does not start with the error code name", name) + } + lowerComment := strings.ToLower(strings.TrimPrefix(doc, name)) + for _, bad := range forbiddenInComment { + if strings.Contains(lowerComment, bad) { + t.Errorf("doc for %q contains forbidden word %q", name, bad) + } + } + }) + + if testing.Verbose() { + var totChars, totCount int + for chars, count := range nameHist { + totChars += chars * count + totCount += count + } + avg := float64(totChars) / float64(totCount) + fmt.Println() + fmt.Printf("%d error codes\n", totCount) + fmt.Printf("average length: %.2f chars\n", avg) + fmt.Printf("max length: %d (%s)\n", len(longestName), longestName) + } +} -- 2.50.0