diff --git a/tools/gn/copy_target_generator.h b/tools/gn/copy_target_generator.h
index 81fbb69..b05855f 100644
--- a/tools/gn/copy_target_generator.h
+++ b/tools/gn/copy_target_generator.h
@@ -21,8 +21,6 @@
   void DoRun() override;
 
  private:
-  void FillDestDir();
-
   DISALLOW_COPY_AND_ASSIGN(CopyTargetGenerator);
 };
 
diff --git a/tools/gn/function_toolchain.cc b/tools/gn/function_toolchain.cc
index 3e272c9..9eeae98 100644
--- a/tools/gn/function_toolchain.cc
+++ b/tools/gn/function_toolchain.cc
@@ -816,8 +816,8 @@
     subst_validator = &IsValidCopySubstitution;
     subst_output_validator = &IsValidCopySubstitution;
   } else {
-    subst_validator = &IsValidToolSubstutition;
-    subst_output_validator = &IsValidToolSubstutition;
+    subst_validator = &IsValidToolSubstitution;
+    subst_output_validator = &IsValidToolSubstitution;
   }
 
   scoped_ptr<Tool> tool(new Tool);
diff --git a/tools/gn/substitution_list.h b/tools/gn/substitution_list.h
index 7273ece..eaf8a61 100644
--- a/tools/gn/substitution_list.h
+++ b/tools/gn/substitution_list.h
@@ -30,7 +30,7 @@
 
   const std::vector<SubstitutionPattern>& list() const { return list_; }
 
-  // Returns a list of all substitution types used by the patterns in thist
+  // Returns a list of all substitution types used by the patterns in this
   // list, with the exception of LITERAL.
   const std::vector<SubstitutionType>& required_types() const {
     return required_types_;
diff --git a/tools/gn/substitution_type.cc b/tools/gn/substitution_type.cc
index b92c756..b66e087 100644
--- a/tools/gn/substitution_type.cc
+++ b/tools/gn/substitution_type.cc
@@ -127,7 +127,7 @@
          type == SUBSTITUTION_SOURCE_OUT_DIR;
 }
 
-bool IsValidToolSubstutition(SubstitutionType type) {
+bool IsValidToolSubstitution(SubstitutionType type) {
   return type == SUBSTITUTION_LITERAL ||
          type == SUBSTITUTION_OUTPUT ||
          type == SUBSTITUTION_LABEL ||
@@ -140,7 +140,7 @@
 }
 
 bool IsValidCompilerSubstitution(SubstitutionType type) {
-  return IsValidToolSubstutition(type) ||
+  return IsValidToolSubstitution(type) ||
          IsValidSourceSubstitution(type) ||
          type == SUBSTITUTION_SOURCE ||
          type == SUBSTITUTION_ASMFLAGS ||
@@ -155,12 +155,12 @@
 
 bool IsValidCompilerOutputsSubstitution(SubstitutionType type) {
   // All tool types except "output" (which would be infinitely recursive).
-  return (IsValidToolSubstutition(type) && type != SUBSTITUTION_OUTPUT) ||
+  return (IsValidToolSubstitution(type) && type != SUBSTITUTION_OUTPUT) ||
          IsValidSourceSubstitution(type);
 }
 
 bool IsValidLinkerSubstitution(SubstitutionType type) {
-  return IsValidToolSubstutition(type) ||
+  return IsValidToolSubstitution(type) ||
          type == SUBSTITUTION_LINKER_INPUTS ||
          type == SUBSTITUTION_LINKER_INPUTS_NEWLINE ||
          type == SUBSTITUTION_LDFLAGS ||
@@ -176,7 +176,7 @@
 }
 
 bool IsValidCopySubstitution(SubstitutionType type) {
-  return IsValidToolSubstutition(type) ||
+  return IsValidToolSubstitution(type) ||
          type == SUBSTITUTION_SOURCE;
 }
 
@@ -187,7 +187,7 @@
   for (size_t i = 0; i < types.size(); i++) {
     if (!IsValidSourceSubstitution(types[i])) {
       *err = Err(origin, "Invalid substitution type.",
-          "The substitution " + std::string(kSubstitutionNames[i]) +
+          "The substitution " + std::string(kSubstitutionNames[types[i]]) +
           " isn't valid for something\n"
           "operating on a source file such as this.");
       return false;
diff --git a/tools/gn/substitution_type.h b/tools/gn/substitution_type.h
index dfe9b54..02787b1 100644
--- a/tools/gn/substitution_type.h
+++ b/tools/gn/substitution_type.h
@@ -11,7 +11,7 @@
 class ParseNode;
 
 // Keep kSubstitutionNames, kSubstitutionNinjaNames and the
-// IsValid*Substutition functions in sync if you change anything here.
+// IsValid*Substitution functions in sync if you change anything here.
 enum SubstitutionType {
   SUBSTITUTION_LITERAL = 0,
 
@@ -93,13 +93,13 @@
 
 // Returns true if the given substitution pattern references the output
 // directory. This is used to check strings that begin with a substitution to
-// verify that the produce a file in the output directory.
+// verify that they produce a file in the output directory.
 bool SubstitutionIsInOutputDir(SubstitutionType type);
 
 // Returns true if the given substitution is valid for the named purpose.
 bool IsValidSourceSubstitution(SubstitutionType type);
 // Both compiler and linker tools.
-bool IsValidToolSubstutition(SubstitutionType type);
+bool IsValidToolSubstitution(SubstitutionType type);
 bool IsValidCompilerSubstitution(SubstitutionType type);
 bool IsValidCompilerOutputsSubstitution(SubstitutionType type);
 bool IsValidLinkerSubstitution(SubstitutionType type);
diff --git a/tools/gn/substitution_writer.cc b/tools/gn/substitution_writer.cc
index 2af2e18..99abced 100644
--- a/tools/gn/substitution_writer.cc
+++ b/tools/gn/substitution_writer.cc
@@ -69,7 +69,7 @@
     "  {{source_name_part}}\n"
     "      The filename part of the source file with no directory or\n"
     "      extension. This will generally be used for specifying a\n"
-    "      transformation from a soruce file to a destination file with the\n"
+    "      transformation from a source file to a destination file with the\n"
     "      same name but different extension.\n"
     "        \"//foo/bar/baz.txt\" => \"baz\"\n"
     "\n"
@@ -174,7 +174,7 @@
   for (const auto& pattern : list.list()) {
     CHECK(pattern.ranges().size() == 1 &&
           pattern.ranges()[0].type == SUBSTITUTION_LITERAL)
-        << "The substitution patterm \""
+        << "The substitution pattern \""
         << pattern.AsString()
         << "\" was expected to be a literal with no {{substitutions}}.";
     const std::string& literal = pattern.ranges()[0].literal;
diff --git a/tools/gn/substitution_writer.h b/tools/gn/substitution_writer.h
index f50fb8d..a450bbb 100644
--- a/tools/gn/substitution_writer.h
+++ b/tools/gn/substitution_writer.h
@@ -115,7 +115,7 @@
       std::vector<OutputFile>* output);
 
   // Like ApplyListToSource but applies the list to all sources and replaces
-  // rather than appesnds the output (this produces the complete output).
+  // rather than appends the output (this produces the complete output).
   static void ApplyListToSources(
       const Settings* settings,
       const SubstitutionList& list,
diff --git a/tools/gn/toolchain.h b/tools/gn/toolchain.h
index b49153b..bcc70c0 100644
--- a/tools/gn/toolchain.h
+++ b/tools/gn/toolchain.h
@@ -99,7 +99,7 @@
 
   // Returns the tool that produces the final output for the given target type.
   // This isn't necessarily the tool you would expect. For copy target, this
-  // will return the stamp tool ionstead since the final output of a copy
+  // will return the stamp tool instead since the final output of a copy
   // target is to stamp the set of copies done so there is one output.
   static ToolType GetToolTypeForTargetFinalOutput(const Target* target);
   const Tool* GetToolForTargetFinalOutput(const Target* target) const;
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index c0bf6cb..0242904 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -824,7 +824,8 @@
     "\n"
     "  For action and action_foreach targets, inputs should be the inputs to\n"
     "  script that don't vary. These should be all .py files that the script\n"
-    "  uses via imports (the main script itself will be an implcit dependency\n"
+    "  uses via imports (the main script itself will be an implicit dependency"
+                                                                            "\n"
     "  of the action so need not be listed).\n"
     "\n"
     "  For action targets, inputs and sources are treated the same, but from\n"