Fixed some common grammatical errors in the comments.

include/swift/Sema/ConstraintSystem.h

@@ -1383,11 +1383,11 @@ enum class ConstraintSystemFlags {
 
   /// If set, verbose output is enabled for this constraint system.
   ///
-  /// Note that this flag is automatically applied to all constraint systems
+  /// Note that this flag is automatically applied to all constraint systems,
   /// when \c DebugConstraintSolver is set in \c TypeCheckerOptions. It can be
   /// automatically enabled for select constraint solving attempts by setting
-  /// \c DebugConstraintSolverAttempt. Finally, it be automatically enabled
-  /// for a pre-configured set of expressions on line numbers by setting
+  /// \c DebugConstraintSolverAttempt. Finally, it can also be automatically 
+  /// enabled for a pre-configured set of expressions on line numbers by setting
   /// \c DebugConstraintSolverOnLines.
   DebugConstraints = 0x10,
 
@@ -2374,7 +2374,7 @@ class ConstraintSystem {
      /// The best solution computed so far.
     Optional<Score> BestScore;
 
-    /// The number of the solution attempt we're looking at.
+    /// The number of the solution attempts we're looking at.
     unsigned SolutionAttempt;
 
     /// Refers to the innermost partial solution scope.
@@ -2521,8 +2521,8 @@ class ConstraintSystem {
 
   private:
     /// The list of constraints that have been retired along the
-    /// current path, this list is used in LIFO fashion when constraints
-    /// are added back to the circulation.
+    /// current path, this list is used in LIFO fashion when
+    /// constraints are added back to the circulation.
     ConstraintList retiredConstraints;
 
     /// The set of constraints which were active at the time of this state
@@ -2821,8 +2821,8 @@ class ConstraintSystem {
   /// able to emit an error message, or false if none of the fixits worked out.
   bool applySolutionFixes(const Solution &solution);
 
-  /// If there is more than one viable solution,
-  /// attempt to pick the best solution and remove all of the rest.
+  /// If there is more than one viable solution, attempt 
+  /// to pick the best solution and remove all of the rest.
   ///
   /// \param solutions The set of solutions to filter.
   ///
@@ -2865,7 +2865,7 @@ class ConstraintSystem {
   void addKeyPathApplicationRootConstraint(Type root, ConstraintLocatorBuilder locator);
 
 public:
-  /// Lookup for a member with the given name in the given base type.
+  /// Lookup for a member with the given name which is in the given base type.
   ///
   /// This routine caches the results of member lookups in the top constraint
   /// system, to avoid.
@@ -3955,7 +3955,7 @@ class ConstraintSystem {
   }
 
 private:
-  /// Adjust the constraint system to accomodate the given selected overload, and
+  /// Adjust the constraint system to accommodate the given selected overload, and
   /// recompute the type of the referenced declaration.
   ///
   /// \returns a pair containing the adjusted opened type of a reference to

lib/SILOptimizer/Transforms/SimplifyCFG.cpp

@@ -57,7 +57,7 @@ STATISTIC(NumSROAArguments, "Number of aggregate argument levels split by "
 //===----------------------------------------------------------------------===//
 
 /// dominatorBasedSimplify iterates between dominator based simplification of
-/// terminator branch condition values and cfg simplification. This is the
+/// terminator branch condition values and CFG simplification. This is the
 /// maximum number of iterations we run. The number is the maximum number of
 /// iterations encountered when compiling the stdlib on April 2 2015.
 ///
@@ -386,8 +386,8 @@ bool SimplifyCFG::threadEdge(const ThreadInfo &ti) {
   return true;
 }
 
-/// Give a cond_br or switch_enum instruction and one successor block return
-/// true if we can infer the value of the condition/enum along the edge to this
+/// Give a cond_br or switch_enum instruction and one successor block returns
+/// true if we can infer the value of the condition/enum along the edge to these
 /// successor blocks.
 static bool isKnownEdgeValue(TermInst *Term, SILBasicBlock *SuccBB,
                              EnumElementDecl *&EnumCase) {
@@ -1045,7 +1045,7 @@ bool SimplifyCFG::tryJumpThreading(BranchInst *BI) {
 
   // Jump threading only makes sense if there is an argument on the branch
   // (which is reacted on in the DestBB), or if this goes through a memory
-  // location (switch_enum_addr is the only adress-instruction which we
+  // location (switch_enum_addr is the only address-instruction which we
   // currently handle).
   if (BI->getArgs().empty() && !isa<SwitchEnumAddrInst>(destTerminator))
     return false;
@@ -1976,7 +1976,7 @@ static bool containsOnlyObjMethodCallOnOptional(SILValue optionalValue,
 }
 
 /// Check that all that noneBB does is forwarding none.
-/// The only other allowed operation are ref count operations.
+/// The only other allowed operations are ref count operations.
 static bool onlyForwardsNone(SILBasicBlock *noneBB, SILBasicBlock *someBB,
                              SwitchEnumInst *SEI) {
   // It all the basic blocks leading up to the ultimate block we only expect
@@ -2054,7 +2054,7 @@ static bool hasSameUltimateSuccessor(SILBasicBlock *noneBB, SILBasicBlock *someB
 
   // Otherwise, lets begin a traversal along the successors of noneSuccessorBB,
   // searching for someSuccessorBB, being careful to only allow for blocks to be
-  // visited once. This enables us to guarantee that there are not any loops or
+  // visited once. This enables us to guarantee that there no loops or
   // any sub-diamonds in the part of the CFG we are traversing. This /does/
   // allow for side-entrances to the region from blocks not reachable from
   // noneSuccessorBB. See function level comment above.
@@ -4048,13 +4048,13 @@ bool SimplifyCFG::simplifyProgramTerminationBlock(SILBasicBlock *BB) {
   //
   // TODO: should we use ProgramTerminationAnalysis ?. The reason we do not
   // use the analysis is because the CFG is likely to be invalidated right
-  // after this pass, o we do not really get the benefit of reusing the
+  // after this pass, that's why we do not really get the benefit of reusing the
   // computation for the next iteration of the pass.
   if (!isARCInertTrapBB(BB))
     return false;
 
   // This is going to be the last basic block this program is going to execute
-  // and this block is inert from the ARC's prospective, no point to do any
+  // and this block is inert from the ARC's prospective,so there's no point to do any
   // releases at this point.
   bool Changed = false;
   llvm::SmallPtrSet<SILInstruction *, 4> InstsToRemove;

lib/Sema/CSDiagnostics.cpp

@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements diagnostics for constraint system.
+// This file implements diagnostics for the constraint system.
 //
 //===----------------------------------------------------------------------===//
 
@@ -2790,7 +2790,7 @@ bool ContextualFailure::diagnoseConversionToBool() const {
     // Check if we need the inner parentheses.
     // Technically we only need them if there's something in 'expr' with
     // lower precedence than '!=', but the code actually comes out nicer
-    // in most cases with parens on anything non-trivial.
+    // in most cases with parens on anything that is non-trivial.
     if (anchor->canAppendPostfixExpression()) {
       prefix = prefix.drop_back();
       suffix = suffix.drop_front();
@@ -4535,7 +4535,7 @@ bool MissingArgumentsFailure::diagnoseSingleMissingArgument() const {
   // corresponding to the missing argument doesn't support a trailing closure,
   // don't provide a Fix-It.
   // FIXME: It's possible to parenthesize and relabel the argument list to
-  // accomodate this, but it's tricky.
+  // accommodate this, but it's tricky.
   bool shouldEmitFixIt =
     !(insertingTrailingClosure && !paramAcceptsTrailingClosure);
 

stdlib/public/runtime/SwiftDtoa.cpp

@@ -40,12 +40,12 @@
 ///
 /// * Fast.  It uses only fixed-width integer arithmetic and has
 ///   constant memory requirements.  For double-precision values on
-///   64-bit processors, it is competitive with Ryu.  For double-precision
+///   64-bit processors, it is competitive with Ryu. For double-precision
 ///   values on 32-bit processors, and higher-precision values on all
 ///   processors, it is considerably faster.
 ///
 /// * Always Accurate. Converting the decimal form back to binary
-///   will always yield exactly the same value.  For the IEEE 754
+///   will always yield exactly the same value. For the IEEE 754
 ///   formats, the round-trip will produce exactly the same bit
 ///   pattern in memory.
 ///
@@ -125,7 +125,7 @@ static void intervalContainingPowerOf10_Binary32(int p, uint64_t *lower, uint64_
 #endif
 
 //
-// Helpers used by binary32, binary64, float80, and binary128
+// Helpers used by binary32, binary64, float80, and binary128.
 //
 
 #if SWIFT_DTOA_BINARY32_SUPPORT || SWIFT_DTOA_BINARY64_SUPPORT || SWIFT_DTOA_FLOAT80_SUPPORT || SWIFT_DTOA_BINARY128_SUPPORT
@@ -782,7 +782,7 @@ size_t swift_dtoa_optimal_binary64_p(const void *d, char *dest, size_t length)
     // bias.  That's because they treat the significand as a
     // fixed-point number with one bit (the hidden bit) integer
     // portion.  The logic here reconstructs the significand as a
-    // pure fraction, so we need to accomodate that when
+    // pure fraction, so we need to accommodate that when
     // reconstructing the binary exponent.
     static const int64_t exponentBias = (1 << (exponentBitCount - 1)) - 2; // 1022
 
@@ -911,14 +911,14 @@ size_t swift_dtoa_optimal_binary64_p(const void *d, char *dest, size_t length)
         // This ensures accuracy but, as explained in Loitsch' paper,
         // this carries a risk that there will be a shorter digit
         // sequence outside of our narrowed interval that we will
-        // miss.  This risk obviously gets lower with increased
+        // miss. This risk obviously gets lower with increased
         // precision, but it wasn't until the Errol paper that anyone
         // had a good way to test whether a particular implementation
-        // had sufficient precision.  That paper shows a way to enumerate
+        // had sufficient precision. That paper shows a way to enumerate
         // the worst-case numbers; those numbers that are extremely close
         // to the mid-points between adjacent floating-point values.
         // These are the values that might sit just outside of the
-        // narrowed interval.  By testing these values, we can verify
+        // narrowed interval. By testing these values, we can verify
         // the correctness of our implementation.
 
         // Multiply out the upper midpoint, rounding down...
@@ -1202,7 +1202,8 @@ size_t swift_dtoa_optimal_binary64_p(const void *d, char *dest, size_t length)
       // value 0.1234 and computed u = 0.1257, l = 0.1211.  The above
       // digit generation works with `u`, so produces 0.125.  But the
       // values 0.122, 0.123, and 0.124 are just as short and 0.123 is
-      // the best choice, since it's closest to the original value.
+      // therefore the best choice, since it's closest to the original
+      // value.
 
       // We know delta and t are both less than 10.0 here, so we can
       // shed some excess integer bits to simplify the following:

test/Sanitizers/asan/recover.swift

@@ -2,7 +2,7 @@
 // REQUIRES: asan_runtime
 // UNSUPPORTED: windows
 
-// Check with recovery instrumentation and runtime option to continue execution.
+// Check with recovery instrumentation and the runtime option to continue execution.
 // RUN: %target-swiftc_driver %s -target %sanitizers-target-triple -g -sanitize=address -sanitize-recover=address -import-objc-header %S/asan_interface.h -emit-ir -o %t.asan_recover.ll
 // RUN: %FileCheck -check-prefix=CHECK-IR -input-file=%t.asan_recover.ll %s
 // RUN: %target-swiftc_driver %s -target %sanitizers-target-triple -g -sanitize=address -sanitize-recover=address -import-objc-header %S/asan_interface.h -o %t_asan_recover
@@ -29,7 +29,7 @@
 // CHECK-IR-NOT: call {{.+}} @memcpy
 
 // FIXME: We need this so we can flush stdout but this won't
-// work on other Platforms (e.g. Windows).
+// work on other Platforms (e.g. Microsoft Windows).
 #if canImport(Glibc)
     import Glibc
 #else
@@ -66,7 +66,7 @@ __asan_poison_memory_region(UnsafeMutableRawPointer(x), size)
 // print(x)
 // ```
 //
-// However, this generated code that called into memcpy rather than performing
+// However, this generated code that's called into memcpy rather than performing
 // a direct read which meant that ASan caught an issue via its interceptors
 // rather than from instrumentation, which does not test the right thing here.
 //
@@ -88,7 +88,7 @@ fflush(stdout)
 // CHECK-RECOVER-STDOUT: Read first element:0
 
 // Second error
-// NOTE: Very loose regex is to accomodate if name demangling
+// NOTE: Very loose regex is to accommodate if name demangling
 // fails. rdar://problem/57235673
 // CHECK-RECOVER-STDERR: AddressSanitizer: use-after-poison
 // CHECK-RECOVER-STDERR: #0 0x{{.+}} in {{.*}}foo{{.*}}