| // 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 typesinternal |
| |
| //go:generate stringer -type=ErrorCode |
| |
| 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 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 |
| |
| /* package names */ |
| |
| // 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 |
| |
| /* imports */ |
| |
| // 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 |
| |
| /* initialization */ |
| |
| // InvalidInitCycle occurs when an invalid cycle is detected within the |
| // initialization graph. |
| // |
| // Example: |
| // var x int = f() |
| // |
| // func f() int { return x } |
| InvalidInitCycle |
| |
| /* decls */ |
| |
| // 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: |
| // import "unsafe" |
| // |
| // type T struct { |
| // a [n]int |
| // } |
| // |
| // var n = unsafe.Sizeof(T{}) |
| 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 |
| |
| /* decls > const */ |
| |
| // 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 |
| |
| /* decls > var (+ other variable assignment codes) */ |
| |
| // 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 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 |
| |
| /* decls > type (+ other type expression codes) */ |
| |
| // 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. |
| // |
| // Example: |
| // type T struct {} |
| // |
| // func (T) m() |
| // |
| // type I interface { |
| // T |
| // } |
| InvalidIfaceEmbed |
| |
| // 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 |
| |
| /* decls > func and method */ |
| |
| // 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 |
| |
| /* decls > special */ |
| |
| // 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. |
| // |
| // Example: |
| // func init() int { return 1 } |
| InvalidInitSig |
| |
| // InvalidInitDecl occurs when init is declared as anything other than a |
| // function. |
| // |
| // Example: |
| // var init = 1 |
| InvalidInitDecl |
| |
| // InvalidMainDecl occurs when main is declared as anything other than a |
| // function, in a main package. |
| InvalidMainDecl |
| |
| /* exprs */ |
| |
| // 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 |
| |
| /* exprs > const */ |
| |
| // 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 |
| |
| /* exprs > operation */ |
| |
| // 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 |
| |
| /* exprs > ptr */ |
| |
| // 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 |
| |
| /* exprs > [] */ |
| |
| // 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 |
| |
| /* operators > slice */ |
| |
| // 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 |
| |
| /* exprs > shift */ |
| |
| // 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 |
| |
| /* exprs > chan */ |
| |
| // 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 |
| |
| /* exprs > literal */ |
| |
| // 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 |
| |
| /* exprs > selector */ |
| |
| // 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 |
| |
| /* exprs > ... */ |
| |
| // 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 to a function call. |
| // |
| // Example: |
| // func printArgs(args ...int) { |
| // for _, a := range args { |
| // println(a) |
| // } |
| // } |
| // |
| // func f() { |
| // a := []int{1,2,3} |
| // printArgs(0, a...) |
| // } |
| MisplacedDotDotDot |
| |
| // InvalidDotDotDotOperand occurs when a "..." operator is applied to a |
| // single-valued operand. |
| // |
| // Example: |
| // func printArgs(args ...int) { |
| // for _, a := range args { |
| // println(a) |
| // } |
| // } |
| // |
| // func f() { |
| // a := 1 |
| // printArgs(a...) |
| // } |
| // |
| // Example: |
| // func args() (int, int) { |
| // return 1, 2 |
| // } |
| // |
| // func printArgs(args ...int) { |
| // for _, a := range args { |
| // println(a) |
| // } |
| // } |
| // |
| // func g() { |
| // printArgs(args()...) |
| // } |
| InvalidDotDotDotOperand |
| |
| // 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 |
| |
| /* exprs > built-in */ |
| |
| // 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#Lengthand_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#Appendingand_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#Lengthand_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#Makingslices_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 |
| |
| /* exprs > assertion */ |
| |
| // 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 |
| |
| /* exprs > conversion */ |
| |
| // 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 an 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 + "" |
| InvalidUntypedConversion |
| |
| /* offsetof */ |
| |
| // 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 |
| |
| /* control flow > scope */ |
| |
| // 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 |
| |
| /* control flow > if */ |
| |
| // InvalidCond occurs when an if condition is not a boolean expression. |
| // |
| // Example: |
| // func checkReturn(i int) { |
| // if i { |
| // panic("non-zero return") |
| // } |
| // } |
| InvalidCond |
| |
| /* control flow > for */ |
| |
| // 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 occurs when a send-only channel used in a range |
| // expression. |
| // |
| // Example: |
| // func sum(c chan<- int) { |
| // s := 0 |
| // for i := range c { |
| // s += i |
| // } |
| // } |
| InvalidChanRange |
| |
| // 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 |
| |
| /* control flow > switch */ |
| |
| // 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 |
| |
| /* control flow > select */ |
| |
| // 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 |
| |
| /* control flow > labels and jumps */ |
| |
| // 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 but 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 |
| |
| /* control flow > calls */ |
| |
| // 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 |
| |
| /* control flow > suspended */ |
| |
| // 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 |
| ) |