Merge pull request github#4731 from criemen/remove-cpp-abstract

C++: Remove uses of abstract from the standard library.

Author: jbj

cpp/ql/src/semmle/code/cpp/Class.qll

@@ -977,7 +977,12 @@ class ClassTemplateInstantiation extends Class {
  * specialization - see `FullClassTemplateSpecialization` and
  * `PartialClassTemplateSpecialization`).
  */
-abstract class ClassTemplateSpecialization extends Class {
+class ClassTemplateSpecialization extends Class {
+  ClassTemplateSpecialization() {
+    isFullClassTemplateSpecialization(this) or
+    isPartialClassTemplateSpecialization(this)
+  }
+
   /**
    * Gets the primary template for the specialization, for example on
    * `S<T,int>`, the result is `S<T,U>`.
@@ -997,6 +1002,16 @@ abstract class ClassTemplateSpecialization extends Class {
   override string getAPrimaryQlClass() { result = "ClassTemplateSpecialization" }
 }
 
+private predicate isFullClassTemplateSpecialization(Class c) {
+  // This class has template arguments, but none of them involves a template parameter.
+  exists(c.getATemplateArgument()) and
+  not exists(Type ta | ta = c.getATemplateArgument() and ta.involvesTemplateParameter()) and
+  // This class does not have any instantiations.
+  not exists(c.(TemplateClass).getAnInstantiation()) and
+  // This class is not an instantiation of a class template.
+  not c instanceof ClassTemplateInstantiation
+}
+
 /**
  * A full specialization of a class template.  For example `MyTemplateClass<int>`
  * in the following code is a `FullClassTemplateSpecialization`:
@@ -1013,19 +1028,31 @@ abstract class ClassTemplateSpecialization extends Class {
  * ```
  */
 class FullClassTemplateSpecialization extends ClassTemplateSpecialization {
-  FullClassTemplateSpecialization() {
-    // This class has template arguments, but none of them involves a template parameter.
-    exists(getATemplateArgument()) and
-    not exists(Type ta | ta = getATemplateArgument() and ta.involvesTemplateParameter()) and
-    // This class does not have any instantiations.
-    not exists(this.(TemplateClass).getAnInstantiation()) and
-    // This class is not an instantiation of a class template.
-    not this instanceof ClassTemplateInstantiation
-  }
+  FullClassTemplateSpecialization() { isFullClassTemplateSpecialization(this) }
 
   override string getAPrimaryQlClass() { result = "FullClassTemplateSpecialization" }
 }
 
+private predicate isPartialClassTemplateSpecialization(Class c) {
+  /*
+   * (a) At least one of this class's template arguments involves a
+   *     template parameter in some respect, for example T, T*, etc.
+   *
+   * (b) It is not the case that the n template arguments of this class
+   *     are a set of n distinct template parameters.
+   *
+   * template <typename T,U> class X {};      // class template
+   * template <typename T> class X<T,T> {};   // partial class template specialization
+   * template <typename T> class X<T,int> {}; // partial class template specialization
+   * template <typename T> class Y {};        // class template
+   * template <typename T> class Y<T*> {};    // partial class template specialization
+   */
+
+  exists(Type ta | ta = c.getATemplateArgument() and ta.involvesTemplateParameter()) and
+  count(TemplateParameter tp | tp = c.getATemplateArgument()) !=
+    count(int i | exists(c.getTemplateArgument(i)))
+}
+
 /**
  * A partial specialization of a class template.  For example `MyTemplateClass<int, T>`
  * in the following code is a `PartialClassTemplateSpecialization`:
@@ -1042,25 +1069,7 @@ class FullClassTemplateSpecialization extends ClassTemplateSpecialization {
  * ```
  */
 class PartialClassTemplateSpecialization extends ClassTemplateSpecialization {
-  PartialClassTemplateSpecialization() {
-    /*
-     * (a) At least one of this class's template arguments involves a
-     *     template parameter in some respect, for example T, T*, etc.
-     *
-     * (b) It is not the case that the n template arguments of this class
-     *     are a set of n distinct template parameters.
-     *
-     * template <typename T,U> class X {};      // class template
-     * template <typename T> class X<T,T> {};   // partial class template specialization
-     * template <typename T> class X<T,int> {}; // partial class template specialization
-     * template <typename T> class Y {};        // class template
-     * template <typename T> class Y<T*> {};    // partial class template specialization
-     */
-
-    exists(Type ta | ta = getATemplateArgument() and ta.involvesTemplateParameter()) and
-    count(TemplateParameter tp | tp = getATemplateArgument()) !=
-      count(int i | exists(getTemplateArgument(i)))
-  }
+  PartialClassTemplateSpecialization() { isPartialClassTemplateSpecialization(this) }
 
   override string getAPrimaryQlClass() { result = "PartialClassTemplateSpecialization" }
 }

cpp/ql/src/semmle/code/cpp/MemberFunction.qll

@@ -205,12 +205,21 @@ class Constructor extends MemberFunction {
 /**
  * A function that defines an implicit conversion.
  */
-abstract class ImplicitConversionFunction extends MemberFunction {
+class ImplicitConversionFunction extends MemberFunction {
+  ImplicitConversionFunction() {
+    // ConversionOperator
+    functions(underlyingElement(this), _, 4)
+    or
+    // ConversionConstructor (deprecated)
+    strictcount(Parameter p | p = getAParameter() and not p.hasInitializer()) = 1 and
+    not hasSpecifier("explicit")
+  }
+
   /** Gets the type this `ImplicitConversionFunction` takes as input. */
-  abstract Type getSourceType();
+  Type getSourceType() { none() } // overridden in subclasses
 
   /** Gets the type this `ImplicitConversionFunction` converts to. */
-  abstract Type getDestType();
+  Type getDestType() { none() } // overridden in subclasses
 }
 
 /**

cpp/ql/src/semmle/code/cpp/Print.qll

@@ -60,7 +60,7 @@ private string getTemplateArgumentString(Declaration d, int i) {
 /**
  * A `Declaration` extended to add methods for generating strings useful only for dumps and debugging.
  */
-abstract private class DumpDeclaration extends Declaration {
+private class DumpDeclaration extends Declaration {
   DumpDeclaration() { shouldPrintDeclaration(this) }
 
   /**

cpp/ql/src/semmle/code/cpp/Type.qll

@@ -577,7 +577,9 @@ class BoolType extends IntegralType {
  * unsigned char e, f;
  * ```
  */
-abstract class CharType extends IntegralType { }
+class CharType extends IntegralType {
+  CharType() { builtintypes(underlyingElement(this), _, [5, 6, 7], _, _, _) }
+}
 
 /**
  * The C/C++ `char` type (which is distinct from `signed char` and

cpp/ql/src/semmle/code/cpp/exprs/ComparisonOperation.qll

@@ -64,15 +64,15 @@ class RelationalOperation extends ComparisonOperation, @rel_op_expr {
    * if the overall expression evaluates to `true`; for example on
    * `x <= 20` this is the `20`, and on `y > 0` it is `y`.
    */
-  abstract Expr getGreaterOperand();
+  Expr getGreaterOperand() { none() } // overridden in subclasses
 
   /**
    * Gets the operand on the "lesser" (or "lesser-or-equal") side
    * of this relational expression, that is, the side that is smaller
    * if the overall expression evaluates to `true`; for example on
    * `x <= 20` this is `x`, and on `y > 0` it is the `0`.
    */
-  abstract Expr getLesserOperand();
+  Expr getLesserOperand() { none() } // overridden in subclasses
 }
 
 /**

cpp/ql/src/semmle/code/cpp/exprs/Expr.qll

@@ -838,7 +838,7 @@ class NewOrNewArrayExpr extends Expr, @any_new_expr {
    * For example, for `new int` the result is `int`.
    * For `new int[5]` the result is `int[5]`.
    */
-  abstract Type getAllocatedType();
+  Type getAllocatedType() { none() } // overridden in subclasses
 
   /**
    * Gets the pointer `p` if this expression is of the form `new(p) T...`.

cpp/ql/src/semmle/code/cpp/exprs/Literal.qll

@@ -47,7 +47,17 @@ class LabelLiteral extends Literal {
 }
 
 /** A character literal or a string literal. */
-abstract class TextLiteral extends Literal {
+class TextLiteral extends Literal {
+  TextLiteral() {
+    // String Literal
+    // Note that `AggregateLiteral`s can also have an array type, but they derive from
+    // @aggregateliteral rather than @literal.
+    this.getType() instanceof ArrayType
+    or
+    // Char literal
+    this.getValueText().regexpMatch("(?s)\\s*L?'.*")
+  }
+
   /** Gets a hex escape sequence that appears in the character or string literal (see [lex.ccon] in the C++ Standard). */
   string getAHexEscapeSequence(int occurrence, int offset) {
     result = getValueText().regexpFind("(?<!\\\\)\\\\x[0-9a-fA-F]+", occurrence, offset)

cpp/ql/src/semmle/code/cpp/exprs/LogicalOperation.qll

@@ -39,7 +39,7 @@ class BinaryLogicalOperation extends BinaryOperation, @bin_log_op_expr {
    * is true, `x` and `y` must also be true, so `impliesValue(x, true, true)` and
    * `impliesValue(y, true, true)` hold.
    */
-  abstract predicate impliesValue(Expr part, boolean partIsTrue, boolean wholeIsTrue);
+  predicate impliesValue(Expr part, boolean partIsTrue, boolean wholeIsTrue) { none() } // overridden in subclasses
 }
 
 /**

cpp/ql/src/semmle/code/cpp/internal/QualifiedName.qll

@@ -59,7 +59,7 @@ class Namespace extends @namespace {
   }
 }
 
-abstract class Declaration extends @declaration {
+class Declaration extends @declaration {
   string toString() { result = "QualifiedName Declaration" }
 
   /** Gets the name of this declaration. */