Merge pull request #11701 from owen-mc/go/count-fields-correctly

Go: Count fields correctly

Author: smowton

go/ql/lib/change-notes/2022-12-16-implicit-read-flowstates.md renamed to go/ql/lib/change-notes/2022-11-16-implicit-read-flowstates.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The predicate `getNumParameter` on `FuncTypeExpr` has been changed to actually give the number of parameters. It previously gave the number of parameter declarations. `getNumParameterDecl` has been introduced to preserve this functionality.

go/ql/lib/change-notes/2022-12-15-getnumparameter-changed.md

@@ -194,24 +194,27 @@ class DeclParent extends @declparent, AstNode {
 }
 
 /**
- * An AST node whose children include fields.
+ * An AST node whose children include field declarations.
+ *
+ * A field declaration can be in a struct, a function (for parameter or result
+ * variables), or an interface (in which case it is a method or embedding spec).
  */
 class FieldParent extends @fieldparent, AstNode {
   /**
-   * Gets the `i`th field of this node.
+   * Gets the `i`th field declaration of this node.
    *
-   * Note that the precise indices of fields are considered an implementation detail
-   * and are subject to change without notice.
+   * Note that the precise indices of field declarations are considered an
+   * implementation detail and are subject to change without notice.
    */
   FieldBase getField(int i) { fields(result, this, i) }
 
   /**
-   * Gets a child field of this node in the AST.
+   * Gets a child field declaration of this node in the AST.
    */
   FieldBase getAField() { result = this.getField(_) }
 
   /**
-   * Gets the number of child fields of this node.
+   * Gets the number of child field declarations of this node.
    */
   int getNumFields() { result = count(this.getAField()) }
 }

go/ql/lib/semmle/go/AST.qll

@@ -416,8 +416,35 @@ class AliasSpec extends @aliasspec, TypeSpec { }
 class TypeDefSpec extends @typedefspec, TypeSpec { }
 
 /**
- * A field declaration, of a struct, a function (in which case this is a parameter or result variable),
- * or an interface (in which case this is a method or embedding spec).
+ * A field declaration, in a struct, a function (for parameter or result
+ * variables), or an interface (in which case this is a method or embedding
+ * spec).
+ *
+ * Examples:
+ *
+ * ```go
+ * Name string `json:"name"`
+ * s string
+ * x, y int
+ * p *Point
+ * Close() error
+ * io.Reader
+ * ~int | float32
+ * ```
+ * as in the following code:
+ * ```go
+ * struct {
+ *   io.Reader
+ *   Name string `json:"name"`
+ *   x, y int
+ * }
+ * func (p *Point) f(s string) (x, y int) { }
+ * type MyInterface interface {
+ *   Close() error
+ *   io.Reader
+ *   ~int32 | float32
+ * }
+ * ```
  */
 class FieldBase extends @field, ExprParent {
   /**
@@ -433,6 +460,22 @@ class FieldBase extends @field, ExprParent {
 
 /**
  * A field declaration in a struct type.
+ *
+ * Examples:
+ *
+ * ```go
+ * Name string `json:"name"`
+ * x, y int
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * struct {
+ *   Name string `json:"name"`
+ *   x, y int
+ * }
+ * ```
  */
 class FieldDecl extends FieldBase, Documentable, ExprParent {
   StructTypeExpr st;
@@ -464,6 +507,20 @@ class FieldDecl extends FieldBase, Documentable, ExprParent {
 
 /**
  * An embedded field declaration in a struct.
+ *
+ * Examples:
+ *
+ * ```go
+ * io.Reader
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * struct {
+ *   io.Reader
+ * }
+ * ```
  */
 class EmbeddedFieldDecl extends FieldDecl {
   EmbeddedFieldDecl() { not exists(this.getNameExpr(_)) }
@@ -473,6 +530,20 @@ class EmbeddedFieldDecl extends FieldDecl {
 
 /**
  * A function parameter or result variable declaration.
+ *
+ * Examples:
+ *
+ * ```go
+ * s string
+ * x, y int
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * func f(s string, x, y int) { }
+ * func g() (s string, x, y int){ return }
+ * ```
  */
 class ParameterOrResultDecl extends FieldBase, Documentable, ExprParent {
   int rawIndex;
@@ -507,6 +578,19 @@ class ParameterOrResultDecl extends FieldBase, Documentable, ExprParent {
 
 /**
  * A parameter declaration.
+ *
+ * Examples:
+ *
+ * ```go
+ * s string
+ * x, y int
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * func f(s string, x, y int) { }
+ * ```
  */
 class ParameterDecl extends ParameterOrResultDecl {
   ParameterDecl() { rawIndex >= 0 }
@@ -524,6 +608,20 @@ class ParameterDecl extends ParameterOrResultDecl {
 
 /**
  * A receiver declaration in a function declaration.
+ *
+ * Examples:
+ *
+ * ```go
+ * p *Point
+ * r io.Reader
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * func (p *Point) f() { }
+ * func (r io.Reader) g() { }
+ * ```
  */
 class ReceiverDecl extends FieldBase, Documentable, ExprParent {
   FuncDecl fd;
@@ -547,6 +645,22 @@ class ReceiverDecl extends FieldBase, Documentable, ExprParent {
 
 /**
  * A result variable declaration.
+ *
+ * Examples:
+ *
+ * ```go
+ * error
+ * r io.Reader
+ * x, y int
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * func f(error) { return nil }
+ * func g(r io.Reader) { return nil }
+ * func h(x, y int) { return }
+ * ```
  */
 class ResultVariableDecl extends ParameterOrResultDecl {
   ResultVariableDecl() { rawIndex < 0 }
@@ -564,6 +678,22 @@ class ResultVariableDecl extends ParameterOrResultDecl {
 
 /**
  * A type parameter declaration in a type specification.
+ *
+ * Examples:
+ *
+ * ```go
+ * S, T comparable
+ * U any
+ * K ~int32 | float32
+ * _ any
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * type GenericStruct[S, T comparable, U any, K ~int32 | float32, _ any] struct { }
+ * func GenericFunction[S, T comparable, U any, K ~int32 | float32, _ any]() {}
+ * ```
  */
 class TypeParamDecl extends @typeparamdecl, Documentable, ExprParent {
   TypeParamDecl() { typeparamdecls(this, _, _) }
@@ -615,6 +745,24 @@ class TypeParamDecl extends @typeparamdecl, Documentable, ExprParent {
 
 /**
  * A method or embedding specification in an interface type expression.
+ *
+ * Examples:
+ *
+ * ```go
+ * Close() error
+ * io.Reader
+ * ~int32 | float32
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * type MyInterface interface {
+ *   Close() error
+ *   io.Reader
+ *   ~int32 | float32
+ * }
+ * ```
  */
 class InterfaceMemberSpec extends FieldBase, Documentable, ExprParent {
   InterfaceTypeExpr ite;
@@ -636,6 +784,20 @@ class InterfaceMemberSpec extends FieldBase, Documentable, ExprParent {
 
 /**
  * A method specification in an interface.
+ *
+ * Examples:
+ *
+ * ```go
+ * Close() error
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * type MyInterface interface {
+ *   Close() error
+ * }
+ * ```
  */
 class MethodSpec extends InterfaceMemberSpec {
   Expr name;
@@ -654,6 +816,22 @@ class MethodSpec extends InterfaceMemberSpec {
 
 /**
  * An embedding specification in an interface.
+ *
+ * Examples:
+ *
+ * ```go
+ * io.Reader
+ * ~int32 | float32
+ * ```
+ *
+ * as in the following code:
+ *
+ * ```go
+ * type MyInterface interface {
+ *   io.Reader
+ *   ~int32 | float32
+ * }
+ * ```
  */
 class EmbeddingSpec extends InterfaceMemberSpec {
   EmbeddingSpec() { not exists(this.getChildExpr(1)) }

go/ql/lib/semmle/go/Decls.qll

@@ -980,18 +980,36 @@ class StructTypeExpr extends @structtypeexpr, TypeExpr, FieldParent {
  * Examples:
  *
  * ```go
- * func(a, b int, c float32) (float32, bool)
+ * func(a int, b, c float32) (float32, bool)
  * ```
  */
 class FuncTypeExpr extends @functypeexpr, TypeExpr, ScopeNode, FieldParent {
   /** Gets the `i`th parameter of this function type (0-based). */
   ParameterDecl getParameterDecl(int i) { result = this.getField(i) and i >= 0 }
 
-  /** Gets a parameter of this function type. */
+  /**
+   * Gets a parameter declaration of this function type.
+   *
+   * For example, for `func(a int, b, c float32) (float32, bool)` the result is
+   * `a int` or `b, c float32`.
+   */
   ParameterDecl getAParameterDecl() { result = this.getParameterDecl(_) }
 
-  /** Gets the number of parameters of this function type. */
-  int getNumParameter() { result = count(this.getAParameterDecl()) }
+  /**
+   * Gets the number of parameter declarations of this function type.
+   *
+   * For example, for `func(a int, b, c float32) (float32, bool)` the result is 2:
+   * `a int` and `b, c float32`.
+   */
+  int getNumParameterDecl() { result = count(this.getAParameterDecl()) }
+
+  /**
+   * Gets the number of parameters of this function type.
+   *
+   * For example, for `func(a int, b, c float32) (float32, bool)` the result is 3:
+   * `a`, `b` and `c`.
+   */
+  int getNumParameter() { result = count(this.getAParameterDecl().getANameExpr()) }
 
   /** Gets the `i`th result of this function type (0-based). */
   ResultVariableDecl getResultDecl(int i) { result = this.getField(-(i + 1)) }
@@ -1011,9 +1029,9 @@ class FuncTypeExpr extends @functypeexpr, TypeExpr, ScopeNode, FieldParent {
 
   /** Gets the `i`th child of this node, parameters first followed by results. */
   override AstNode getUniquelyNumberedChild(int i) {
-    if i < this.getNumParameter()
+    if i < this.getNumParameterDecl()
     then result = this.getParameterDecl(i)
-    else result = this.getResultDecl(i - this.getNumParameter())
+    else result = this.getResultDecl(i - this.getNumParameterDecl())
   }
 }