[dataflow] Delete legacy aliases

[sammccall]

Summary

I can't find any trace of use anymore.
I'm not sure renaming the header is worth the break, but leave the FIXME.

clang/include/clang/Analysis/FlowSensitive/MatchSwitch.h

 //===---- MatchSwitch.h -----------------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
-//  This file defines the `MatchSwitch` abstraction for building a "switch"
+//  This file defines the `ASTMatchSwitch` abstraction for building a "switch"
 //  statement, where each case of the switch is defined by an AST matcher. The
 //  cases are considered in order, like pattern matching in functional
 //  languages.
 //
 //  Currently, the design is catered towards simplifying the implementation of
 //  `DataflowAnalysis` transfer functions. Based on experience here, this
 //  library may be generalized and moved to ASTMatchers.
 //
 //===----------------------------------------------------------------------===//
 //
-// FIXME: Rename to ASTMatchSwitch.h and update documentation when all usages of
-// `MatchSwitch` are updated to `ASTMatchSwitch<Stmt>`
+// FIXME: Rename to ASTMatchSwitch.h
 
 #ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_MATCHSWITCH_H_
 #define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_MATCHSWITCH_H_
 
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Stmt.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchers.h"

 template <typename T, typename State, typename Result = void>
 using MatchSwitchAction = std::function<Result(
     const T *, const ast_matchers::MatchFinder::MatchResult &, State &)>;
 
 template <typename BaseT, typename State, typename Result = void>
 using ASTMatchSwitch =
     std::function<Result(const BaseT &, ASTContext &, State &)>;
 
-// FIXME: Remove this alias when all usages of `MatchSwitch` are updated to
-// `ASTMatchSwitch<Stmt>`.
-template <typename State, typename Result = void>
-using MatchSwitch = ASTMatchSwitch<Stmt, State, Result>;
-
 /// Collects cases of a "match switch": a collection of matchers paired with
 /// callbacks, which together define a switch that can be applied to a node
 /// whose type derives from `BaseT`. This structure can simplify the definition
 /// of `transfer` functions that rely on pattern-matching.
 ///
 /// For example, consider an analysis that handles particular function calls. It
 /// can define the `ASTMatchSwitch` once, in the constructor of the analysis,
 /// and then reuse it each time that `transfer` is called, with a fresh state
return DynTypedMatcher::constructVariadic(
         DynTypedMatcher::VO_AnyOf, ASTNodeKind::getFromNodeKind<BaseT>(),
         std::move(Matchers));
   }
 
   std::vector<ast_matchers::internal::DynTypedMatcher> Matchers;
   std::vector<MatchSwitchAction<BaseT, State, Result>> Actions;
 };
 
-// FIXME: Remove this alias when all usages of `MatchSwitchBuilder` are updated
-// to `ASTMatchSwitchBuilder<Stmt>`.
-template <typename State, typename Result = void>
-using MatchSwitchBuilder = ASTMatchSwitchBuilder<Stmt, State, Result>;
-
 } // namespace dataflow
 } // namespace clang
 #endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_MATCHSWITCH_H_