diff --git a/compiler/src/dmd/hdrgen.d b/compiler/src/dmd/hdrgen.d
@@ -2247,6 +2247,16 @@
             buf.writeByte(e.postfix);
     }
 
+    void visitIString(IStringExp e)
+    {
+        buf.writestring("i\"");
+        foreach (c; e.istring)
+        {
+            writeCharLiteral(buf, c);
+        }
+        buf.writeByte('"');
+    }
+
     void visitArrayLiteral(ArrayLiteralExp e)
     {
         buf.writeByte('[');
@@ -2827,6 +2837,7 @@
         case EXP.super_:        return visitSuper(e.isSuperExp());
         case EXP.null_:         return visitNull(e.isNullExp());
         case EXP.string_:       return visitString(e.isStringExp());
+        case EXP.istring:       return visitIString(e.isIStringExp());
         case EXP.arrayLiteral:  return visitArrayLiteral(e.isArrayLiteralExp());
         case EXP.assocArrayLiteral:     return visitAssocArrayLiteral(e.isAssocArrayLiteralExp());
         case EXP.structLiteral: return visitStructLiteral(e.isStructLiteralExp());

diff --git a/compiler/src/dmd/lexer.d b/compiler/src/dmd/lexer.d
@@ -506,6 +506,16 @@ class Lexer
                 }
                 else
                     goto case_ident;
+
+            case 'i':
+                if (p[1] != '"' || Ccompile)
+                    goto case_ident;
+
+                ++p;
+                escapeStringConstant(t);
+                t.value = TOK.istring;
+                return;
+
             case '"':
                 escapeStringConstant(t);
                 return;
@@ -517,7 +527,6 @@ class Lexer
             case 'f':
             case 'g':
             case 'h':
-            case 'i':
             case 'j':
             case 'k':
             case 'l':

diff --git a/compiler/src/dmd/parse.d b/compiler/src/dmd/parse.d
@@ -2014,6 +2014,7 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
         case TOK.charLiteral:
         case TOK.wcharLiteral:
         case TOK.dcharLiteral:
+        case TOK.istring:
         case TOK.string_:
         case TOK.hexadecimalString:
         case TOK.file:
@@ -5819,6 +5820,7 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
         case TOK.null_:
         case TOK.true_:
         case TOK.false_:
+        case TOK.istring:
         case TOK.string_:
         case TOK.hexadecimalString:
         case TOK.leftParenthesis:
@@ -7339,6 +7341,7 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
                     case TOK.charLiteral:
                     case TOK.wcharLiteral:
                     case TOK.dcharLiteral:
+                    case TOK.istring:
                     case TOK.string_:
                     case TOK.hexadecimalString:
                     case TOK.file:
@@ -8255,6 +8258,12 @@ class Parser(AST, Lexer = dmd.lexer.Lexer) : Lexer
                 e.isStringExp().hexString = hexString;
                 break;
             }
+
+        case TOK.istring:
+            e = new AST.IStringExp(loc, token.ustring[0 .. token.len]);
+            nextToken();
+            break;
+
         case TOK.void_:
             t = AST.Type.tvoid;
             goto LabelX;

diff --git a/compiler/src/dmd/parsetimevisitor.d b/compiler/src/dmd/parsetimevisitor.d
@@ -183,6 +183,7 @@
     void visit(AST.TypeidExp e) { visit(cast(AST.Expression)e); }
     void visit(AST.TraitsExp e) { visit(cast(AST.Expression)e); }
     void visit(AST.StringExp e) { visit(cast(AST.Expression)e); }
+    void visit(AST.IStringExp e) { visit(cast(AST.Expression)e); }
     void visit(AST.NewExp e) { visit(cast(AST.Expression)e); }
     void visit(AST.AssocArrayLiteralExp e) { visit(cast(AST.Expression)e); }
     void visit(AST.ArrayLiteralExp e) { visit(cast(AST.Expression)e); }

diff --git a/compiler/src/dmd/strictvisitor.d b/compiler/src/dmd/strictvisitor.d
@@ -138,6 +138,7 @@ extern(C++) class StrictVisitor(AST) : ParseTimeVisitor!AST
     override void visit(AST.TypeidExp) { assert(0); }
     override void visit(AST.TraitsExp) { assert(0); }
     override void visit(AST.StringExp) { assert(0); }
+    override void visit(AST.IStringExp) { assert(0); }
     override void visit(AST.NewExp) { assert(0); }
     override void visit(AST.AssocArrayLiteralExp) { assert(0); }
     override void visit(AST.ArrayLiteralExp) { assert(0); }

diff --git a/compiler/src/dmd/tokens.d b/compiler/src/dmd/tokens.d
@@ -23,6 +23,12 @@
 import dmd.root.rmem;
 import dmd.root.utf;
 
+/* if you change this, remember to update:
+ compiler/test/unit/lexer/location_offset.d
+ compiler/src/tests/cxxfrontend.cc
+ compiler/src/dmd/tokens.h
+*/
+
 enum TOK : ubyte
 {
     reserved,
@@ -124,6 +130,7 @@
     // Leaf operators
     identifier,
     string_,
+    istring,
     hexadecimalString,
     this_,
     super_,
@@ -380,6 +387,7 @@
     // Leaf operators
     identifier,
     string_,
+    istring,
     this_,
     super_,
     halt,
@@ -833,6 +841,7 @@
         // For debugging
         TOK.error: "error",
         TOK.string_: "string",
+        TOK.istring: "istring",
         TOK.onScopeExit: "scope(exit)",
         TOK.onScopeSuccess: "scope(success)",
         TOK.onScopeFailure: "scope(failure)",
@@ -961,6 +970,7 @@
         const bufflen = 3 + 3 * floatvalue.sizeof + 1;
         __gshared char[bufflen + 2] buffer;     // extra 2 for suffixes
         char* p = &buffer[0];
+        char prefix = 0;
         switch (value)
         {
         case TOK.int32Literal:
@@ -1023,8 +1033,14 @@
             p[length + 2] = 0;
             return p[0 .. length + 2];
 
+        case TOK.istring:
+            prefix = 'i';
+            goto case TOK.string_;
+
         case TOK.string_:
             OutBuffer buf;
+            if (prefix)
+                buf.writeByte(prefix);
             buf.writeByte('"');
             for (size_t i = 0; i < len;)
             {

@@ -133,6 +133,7 @@ enum class TOK : unsigned char
     // Leaf operators
     identifier,
     string_,
+    istring,
     hexadecimalString,
     this_,
     super_,
@@ -390,6 +391,7 @@ enum class EXP : unsigned char
     // Leaf operators
     identifier,
     string_,
+    istring,
     this_,
     super_,
     halt,

@@ -195,6 +195,7 @@ class ThisExp;
 class SuperExp;
 class NullExp;
 class StringExp;
+class IStringExp;
 class TupleExp;
 class ArrayLiteralExp;
 class AssocArrayLiteralExp;
@@ -480,6 +481,7 @@ class ParseTimeVisitor
     virtual void visit(TypeidExp *e) { visit((Expression *)e); }
     virtual void visit(TraitsExp *e) { visit((Expression *)e); }
     virtual void visit(StringExp *e) { visit((Expression *)e); }
+    virtual void visit(IStringExp *e) { visit((Expression *)e); }
     virtual void visit(NewExp *e) { visit((Expression *)e); }
     virtual void visit(AssocArrayLiteralExp *e) { visit((Expression *)e); }
     virtual void visit(ArrayLiteralExp *e) { visit((Expression *)e); }

diff --git a/compiler/src/tests/cxxfrontend.cc b/compiler/src/tests/cxxfrontend.cc
@@ -8,6 +8,8 @@
  * Source:      $(LINK2 https://github.com/dlang/dmd/blob/master/src/tests/cxxfrontend.c, _cxxfrontend.c)
  */
 
+#include <stdio.h>
+
 #include "root/array.h"
 #include "root/bitarray.h"
 #include "root/complex_t.h"
@@ -1686,26 +1688,45 @@ void test_backend(FuncDeclaration *f, Type *t)
 
 int main(int argc, char **argv)
 {
+    fprintf(stderr, "cxxfrontend.cc starting test\n");
     frontend_init();
 
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_tokens();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_compiler_globals();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_visitors();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_semantic();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_skip_importall();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_expression();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_target();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_parameters();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_types();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_location();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_array();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_outbuffer();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_cppmangle();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_module();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_optional();
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     test_filename();
 
+    fprintf(stderr, "cxxfrontend.cc %d \n", __LINE__);
     frontend_term();
 
+    fprintf(stderr, "cxxfrontend.cc exit\n");
     return 0;
 }
diff --git a/compiler/test/fail_compilation/dip1027.d b/compiler/test/fail_compilation/dip1027.d
@@ -0,0 +1,14 @@
+/* TEST_OUTPUT:
+---
+fail_compilation/dip1027.d(103): Error: istring ended prematurely
+fail_compilation/dip1027.d(104): Error: identifier expected after $
+---
+*/
+
+#line 100
+
+void test()
+{
+    auto t = i"$";
+    auto u = i"$7";
+}
diff --git a/compiler/test/runnable/dip1027.d b/compiler/test/runnable/dip1027.d
@@ -0,0 +1,27 @@
+/*
+TEST_OUTPUT:
+---
+AliasSeq!("betty %s", 73)
+AliasSeq!("betty %d", 73)
+AliasSeq!("betty %d", 74)
+---
+*/
+import core.stdc.stdio;
+
+int main()
+{
+    enum x = 73;
+    pragma(msg, i"betty $x");
+    pragma(msg, i"betty ${%d}x");
+    pragma(msg, i"betty ${%d}(x + 1)");
+
+    string betty = "betty";
+    printf(i"hello $(betty.ptr)\n");
+
+    int aa = 5;
+    int bb = 10;
+    string s = "ate";
+    printf(i"I $(s.ptr) ${%d}aa apples and ${%d}bb bananas totalling ${%d}(aa + bb) fruits! $$.\n");
+
+    return 0;
+}
diff --git a/compiler/test/unit/lexer/location_offset.d b/compiler/test/unit/lexer/location_offset.d
@@ -502,6 +502,7 @@ enum ignoreTokens
     int128Literal,
     uns128Literal,
     halt,
+    istring,
     tuple,
     error,
     int128,
-Original file line number
+Diff line change
@@ Expand Up / @@ -502,6 +502,7 @@ enum ignoreTokens @@
         int128Literal,
         uns128Literal,
         halt,
+        istring,
         tuple,
         error,
         int128,
@@ Expand Down @@