diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index afdcac8600..57b986cd59 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -51,10 +51,12 @@ jobs:
           # macOS
           - job_name: macOS 13 x64, DMD (latest)
             os: macos-13
-            host_dmd: dmd
+            # FIXME: Revert this back to "dmd" after 2.107.1 is released.
+            host_dmd: ldc
           - job_name: macOS 13 x64, DMD (coverage)
             os: macos-13
-            host_dmd: dmd
+            # FIXME: Revert this back to "dmd" after 2.107.1 is released.
+            host_dmd: ldc
             coverage: true
           - job_name: macOS 12 x64, DMD (bootstrap)
             os: macos-12
@@ -104,6 +106,13 @@ jobs:
         with:
           arch: ${{ env.MODEL == '64' && 'x64' || 'x86' }}
 
+      # NOTE: Linker ICEs with Xcode 15.0.1 (default version on macos-13)
+      # * https://issues.dlang.org/show_bug.cgi?id=24407
+      # Remove this step if the default gets changed to 15.1 in actions/runner-images.
+      - name: 'macOS 13: Switch to Xcode v15.1'
+        if: matrix.os == 'macos-13'
+        run: sudo xcode-select -switch /Applications/Xcode_15.1.app
+
       - name: 'Posix: Install host compiler'
         if: runner.os != 'Windows'
         run: ci/run.sh install_host_compiler
@@ -174,18 +183,18 @@ jobs:
             freebsd_version: '13.2'
             host_dmd: dmd-2.095.0
     name: ${{ matrix.job_name }}
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 50
       - name: Run in VM
-        uses: cross-platform-actions/action@v0.22.0
+        uses: cross-platform-actions/action@v0.23.0
         with:
           operating_system: freebsd
           hypervisor: qemu
-          memory: 8G
+          memory: 12G
           sync_files: runner-to-vm
           version: ${{ matrix.freebsd_version }}
           shell: bash
diff --git a/VERSION b/VERSION
index 1880c9808c..ff56162fdd 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-v2.107.1-rc.1
+v2.107.1
diff --git a/compiler/src/dmd/backend/cgelem.d b/compiler/src/dmd/backend/cgelem.d
index 7e34fe7375..3e99f8fb31 100644
--- a/compiler/src/dmd/backend/cgelem.d
+++ b/compiler/src/dmd/backend/cgelem.d
@@ -5035,14 +5035,9 @@ private elem * el64_32(elem *e, goal_t goal)
         }
         break;
 
-    case OPmul:
-        if (config.exe & (EX_OSX | EX_OSX64)) // https://issues.dlang.org/show_bug.cgi?id=21047
-            break;
-        else
-            goto case;
-
     case OPadd:
     case OPmin:
+    case OPmul:
     case OPor:
     case OPand:
     case OPxor:
diff --git a/compiler/src/dmd/backend/dwarfdbginf.d b/compiler/src/dmd/backend/dwarfdbginf.d
index 7bde5120e0..a7790a2b92 100644
--- a/compiler/src/dmd/backend/dwarfdbginf.d
+++ b/compiler/src/dmd/backend/dwarfdbginf.d
@@ -16,15 +16,19 @@
 Some generic information for debug info on macOS:
 
 The linker on macOS will remove any debug info, i.e. every section with the
-`S_ATTR_DEBUG` flag, this includes everything in the `__DWARF` section. By using
-the `S_REGULAR` flag the linker will not remove this section. This allows to get
-the filenames and line numbers for backtraces from the executable.
+`S_ATTR_DEBUG` flag, this includes everything in the `__DWARF` section.
+Because of this, it is not possible to get filenames and line numbers for
+backtraces from the executable alone.
 
 Normally the linker removes all the debug info but adds a reference to the
 object files. The debugger can then read the object files to get filename and
 line number information. It's also possible to use an additional tool that
 generates a separate `.dSYM` file. This file can then later be deployed with the
 application if debug info is needed when the application is deployed.
+
+Support in core.runtime for getting filename and line number for backtraces
+from these `.dSYM` files will need to be investigated.
+See: https://issues.dlang.org/show_bug.cgi?id=20510
 */
 
 module dmd.backend.dwarfdbginf;
@@ -478,7 +482,7 @@ static if (1)
         {
             name = n;
             if (config.objfmt == OBJ_MACH)
-                flags = S_ATTR_DEBUG;
+                flags = S_REGULAR | S_ATTR_DEBUG;
             else
                 flags = SHT_PROGBITS;
         }
@@ -552,10 +556,7 @@ static if (1)
         debug_abbrev   = Section("__debug_abbrev");
         debug_info     = Section("__debug_info");
         debug_str      = Section("__debug_str");
-        // We use S_REGULAR to make sure the linker doesn't remove this section. Needed
-        // for filenames and line numbers in backtraces.
         debug_line     = Section("__debug_line");
-        debug_line.flags = S_REGULAR;
     }
     void elfDebugSectionsInit()
     {
diff --git a/compiler/src/dmd/backend/mach.d b/compiler/src/dmd/backend/mach.d
index 1686537942..a7078e2766 100644
--- a/compiler/src/dmd/backend/mach.d
+++ b/compiler/src/dmd/backend/mach.d
@@ -94,6 +94,12 @@ enum
     LC_SYMTAB       = 2,
     LC_DYSYMTAB     = 11,
     LC_SEGMENT_64   = 0x19,
+
+    /// Build for MacOSX min OS version.
+    LC_VERSION_MIN_MACOSX = 0x24,
+
+    /// Build for platform min OS version.
+    LC_BUILD_VERSION = 0x32,
 }
 
 struct load_command
@@ -407,3 +413,62 @@ struct scattered_relocation_info
 
     int r_value;
 }
+
+/**
+ * The version_min_command contains the min OS version on which this binary was
+ * built to run.
+ */
+struct version_min_command
+{
+    ///
+    uint cmd = LC_VERSION_MIN_MACOSX;
+
+    ///
+    uint cmdsize = typeof(this).sizeof;
+
+    /// X.Y.Z is encoded in nibbles xxxx.yy.zz
+    uint version_;
+
+    /// X.Y.Z is encoded in nibbles xxxx.yy.zz
+    uint sdk = 0;
+}
+
+/**
+ * The `build_version_command` contains the min OS version on which this binary
+ * was built to run for its platform.
+ */
+struct build_version_command
+{
+    ///
+    uint cmd = LC_BUILD_VERSION;
+
+    ///
+    uint cmdsize = typeof(this).sizeof;
+
+    /// Platform
+    uint platform = PLATFORM_MACOS;
+
+    /// X.Y.Z is encoded in nibbles xxxx.yy.zz
+    uint minos;
+
+    /// X.Y.Z is encoded in nibbles xxxx.yy.zz
+    uint sdk = 0;
+
+    /// Number of tool entries following this
+    uint ntools = 0;
+}
+
+/// Known values for the platform field in `build_version_command`
+enum
+{
+    PLATFORM_MACOS = 1,
+    PLATFORM_IOS = 2,
+    PLATFORM_TVOS = 3,
+    PLATFORM_WATCHOS = 4,
+    PLATFORM_BRIDGEOS = 5,
+    PLATFORM_MACCATALYST = 6,
+    PLATFORM_IOSSIMULATOR = 7,
+    PLATFORM_TVOSSIMULATOR = 8,
+    PLATFORM_WATCHOSSIMULATOR = 9,
+    PLATFORM_DRIVERKIT = 10
+}
diff --git a/compiler/src/dmd/backend/machobj.d b/compiler/src/dmd/backend/machobj.d
index 517d088583..7443f7eb8f 100644
--- a/compiler/src/dmd/backend/machobj.d
+++ b/compiler/src/dmd/backend/machobj.d
@@ -625,6 +625,7 @@ void MachObj_term(const(char)* objfilename)
      *                  { sections }
      *          symtab_command
      *          dysymtab_command
+     *          build_version_command/version_min_command
      *  { segment contents }
      *  { relocations }
      *  symbol table
@@ -632,6 +633,7 @@ void MachObj_term(const(char)* objfilename)
      *  indirect symbol table
      */
 
+    auto version_command = VersionCommand(operatingSystemVersion);
     uint foffset;
     uint headersize;
     uint sizeofcmds;
@@ -645,9 +647,10 @@ void MachObj_term(const(char)* objfilename)
         header.cputype = CPU_TYPE_X86_64;
         header.cpusubtype = CPU_SUBTYPE_I386_ALL;
         header.filetype = MH_OBJECT;
-        header.ncmds = 3;
+        header.ncmds = 4;
         header.sizeofcmds = cast(uint)(segment_command_64.sizeof +
                                 (section_cnt - 1) * section_64.sizeof +
+                            version_command.size +
                             symtab_command.sizeof +
                             dysymtab_command.sizeof);
         header.flags = MH_SUBSECTIONS_VIA_SYMBOLS;
@@ -669,9 +672,10 @@ void MachObj_term(const(char)* objfilename)
         header.cputype = CPU_TYPE_I386;
         header.cpusubtype = CPU_SUBTYPE_I386_ALL;
         header.filetype = MH_OBJECT;
-        header.ncmds = 3;
+        header.ncmds = 4;
         header.sizeofcmds = cast(uint)(segment_command.sizeof +
                                 (section_cnt - 1) * section.sizeof +
+                            version_command.size +
                             symtab_command.sizeof +
                             dysymtab_command.sizeof);
         header.flags = MH_SUBSECTIONS_VIA_SYMBOLS;
@@ -864,6 +868,8 @@ void MachObj_term(const(char)* objfilename)
     }
 
     // Put out relocation data
+    // See mach-o/reloc.h for some examples of what should be generated and when:
+    // https://github.com/apple-oss-distributions/xnu/blob/rel/xnu-10002/EXTERNAL_HEADERS/mach-o/x86_64/reloc.h
     mach_numbersyms();
     for (int seg = 1; seg < SegData.length; seg++)
     {
@@ -975,12 +981,8 @@ void MachObj_term(const(char)* objfilename)
                                     rel.r_type = X86_64_RELOC_SIGNED;
                                 else if ((s.Sfl == FLfunc || s.Sfl == FLextern || s.Sclass == SC.global ||
                                           s.Sclass == SC.comdat || s.Sclass == SC.comdef) && r.rtype == RELaddr)
-                                {
-                                    rel.r_type = X86_64_RELOC_GOT_LOAD;
-                                    if (seg == eh_frame_seg ||
-                                        seg == except_table_seg)
-                                        rel.r_type = X86_64_RELOC_GOT;
-                                }
+                                    rel.r_type = X86_64_RELOC_GOT;
+
                                 rel.r_address = cast(int)r.offset;
                                 rel.r_symbolnum = s.Sxtrnnum;
                                 rel.r_pcrel = 1;
@@ -1352,6 +1354,7 @@ void MachObj_term(const(char)* objfilename)
             sym32.n_sect = sym.n_sect;
             fobjbuf.write(&sym32, sym32.sizeof);
         }
+        dysymtab_cmd.nundefsym++;
         symtab_cmd.nsyms++;
     }
     foffset += symtab_cmd.nsyms * (I64 ? nlist_64.sizeof : nlist.sizeof);
@@ -1399,6 +1402,7 @@ void MachObj_term(const(char)* objfilename)
         fobjbuf.write(&segment_cmd, segment_cmd.sizeof);
         fobjbuf.write(SECbuf.buf + section.sizeof, cast(uint)((section_cnt - 1) * section.sizeof));
     }
+    fobjbuf.write(version_command.data, version_command.size);
     fobjbuf.write(&symtab_cmd, symtab_cmd.sizeof);
     fobjbuf.write(&dysymtab_cmd, dysymtab_cmd.sizeof);
     fobjbuf.position(foffset, 0);
@@ -2823,3 +2827,170 @@ int dwarf_eh_frame_fixup(int dfseg, targ_size_t offset, Symbol *s, targ_size_t v
 
     return I64 ? 8 : 4;
 }
+
+
+private:
+
+/**
+ * Encapsulates the build_version_command/version_min_command load commands.
+ *
+ * For the 10.14 and later SDK, the `build_version_command` load command is used.
+ * For earlier versions, the `version_min_command` load command is used.
+ */
+const struct VersionCommand
+{
+    pure:
+    nothrow:
+    @nogc:
+    @safe:
+
+    private
+    {
+        /**
+         * This is the absolute minimum supported version of macOS (64 bit) for DMD,
+         * as documented at: https://dlang.org/dmd-osx.html#requirements
+         * NOTE: Versions earlier than 10.7 do not support thread local storage.
+         */
+        enum fallbackOSVersion = Version(10, 9).encode;
+
+        /// The first minor version that uses the `build_version_command`.
+        enum firstMinorUsingBuildVersionCommand = 14;
+
+        /// `true` if the `build_version_command` load command should be used.
+        bool useBuild;
+
+        /// The `build_version_command` load command.
+        build_version_command buildVersionCommand;
+
+        /// The `version_min_command` load command.
+        version_min_command versionMinCommand;
+    }
+
+    /**
+     * Initializes the VersionCommand.
+     *
+     * Params:
+     *  os = the version of the operating system
+     */
+    this(Version os)
+    {
+        useBuild = os.minor >= firstMinorUsingBuildVersionCommand;
+
+        const encodedOs = os.isValid ? os.encode : fallbackOSVersion;
+
+        const build_version_command buildVersionCommand = { minos: encodedOs };
+        const version_min_command versionMinCommand = { version_: encodedOs };
+
+        this.buildVersionCommand = buildVersionCommand;
+        this.versionMinCommand = versionMinCommand;
+    }
+
+    /// Returns: the size of the load command.
+    size_t size()
+    {
+        return useBuild ? build_version_command.sizeof : version_min_command.sizeof;
+    }
+
+    /// Returns: the data for the load command.
+    const(void)* data() return
+    {
+        return useBuild ? cast(const(void)*) &buildVersionCommand : cast(const(void)*) &versionMinCommand;
+    }
+}
+
+/// Holds an operating system version or a SDK version.
+immutable struct Version
+{
+    ///
+    int major;
+
+    ///
+    int minor;
+
+    ///
+    int build;
+
+    /// Returns: `true` if the version is valid
+    bool isValid() pure nothrow @nogc @safe
+    {
+        return major >= 10 && major < 100 &&
+            minor >= 0 && minor < 100 &&
+            build >= 0 && build < 100;
+    }
+}
+
+/**
+ * Returns the given version encoded as a single integer.
+ *
+ * Params:
+ *  version_ = the version to encode. Needs to be a valid version
+ *      (`version_.isValid`)
+ *
+ * Returns: the encoded version
+ */
+int encode(Version version_) pure @nogc @safe
+in
+{
+    assert(version_.isValid);
+}
+do
+{
+    with (version_)
+        return major * 2^^16 + minor * 2^^8 + build * 2^^0;
+}
+
+unittest
+{
+    assert(Version(10, 14, 0).encode == 0x0a0e00);
+    assert(Version(10, 14, 1).encode == 0x0a0e01);
+    assert(Version(10, 14, 6).encode == 0x0a0e06);
+    assert(Version(10, 14, 99).encode == 0x0a0e63);
+
+    assert(Version(10, 15, 6).encode == 0x0a0f06);
+
+    assert(Version(10, 16, 0).encode == 0x0a1000);
+    assert(Version(10, 16, 6).encode == 0x0a1006);
+
+    assert(Version(10, 17, 0).encode == 0x0a1100);
+}
+
+/// Returns: the version of the currently running operating system.
+@trusted
+Version operatingSystemVersion()
+{
+    if (const deploymentTarget = getenv("MACOSX_DEPLOYMENT_TARGET"))
+    {
+        const version_ = toVersion(deploymentTarget);
+
+        if (version_.isValid)
+            return version_;
+
+        error(null, 0, 0, "invalid version number in 'MACOSX_DEPLOYMENT_TARGET=%s'", deploymentTarget);
+    }
+    return Version();
+}
+
+/**
+ * Converts the given string to a `Version`.
+ *
+ * Params:
+ *  str = the string to convert. Should have the format `XX.YY(.ZZ)`. Needs to
+ *      be `\0` terminated.
+ *
+ * Returns: the converted `Version`.
+ */
+@trusted
+Version toVersion(const char* str) @nogc
+{
+    import core.stdc.stdio : sscanf;
+
+    if (!str)
+        return Version();
+
+    Version version_;
+
+    with (version_)
+        str.sscanf("%d.%d.%d", &major, &minor, &build);
+
+    return version_;
+}
diff --git a/compiler/src/dmd/cparse.d b/compiler/src/dmd/cparse.d
index e917d2cb7e..aeedb493ef 100644
--- a/compiler/src/dmd/cparse.d
+++ b/compiler/src/dmd/cparse.d
@@ -2155,7 +2155,7 @@ final class CParser(AST) : Parser!AST
                 error("function identifier-list cannot end with `...`");
             ft.parameterList.varargs = AST.VarArg.KRvariadic;   // but C11 allows extra arguments
             auto plLength = pl.length;
-            if (symbols.length != plLength)
+            if (symbols && symbols.length != plLength)
                 error(token.loc, "%d identifiers does not match %d declarations", cast(int)plLength, cast(int)symbols.length);
 
             /* Transfer the types and storage classes from symbols[] to pl[]
@@ -2176,6 +2176,12 @@ final class CParser(AST) : Parser!AST
 
                 if (p.type || !(p.storageClass & STC.parameter))
                     error("storage class and type are not allowed in identifier-list");
+                if (!symbols)
+                {
+                    // Error already given in cparseDeclaration
+                    p.type = AST.Type.terror;
+                    continue;
+                }
                 foreach (s; (*symbols)[]) // yes, quadratic
                 {
                     auto ad = s.isAttribDeclaration();
diff --git a/compiler/src/dmd/dinterpret.d b/compiler/src/dmd/dinterpret.d
index c021b184c6..c4924903f2 100644
--- a/compiler/src/dmd/dinterpret.d
+++ b/compiler/src/dmd/dinterpret.d
@@ -3787,7 +3787,7 @@ public:
             if (v is v2 || !v.isOverlappedWith(v2))
                 continue;
             auto e = (*sle.elements)[i];
-            if (e.op != EXP.void_)
+            if (e !is null && e.op != EXP.void_)
                 (*sle.elements)[i] = voidInitLiteral(e.type, v).copy();
         }
     }
diff --git a/compiler/src/dmd/dmodule.d b/compiler/src/dmd/dmodule.d
index a77e4f303c..58bf3fd075 100644
--- a/compiler/src/dmd/dmodule.d
+++ b/compiler/src/dmd/dmodule.d
@@ -1394,6 +1394,7 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
 {
     enum SourceEncoding { utf16, utf32}
     enum Endian { little, big}
+    immutable loc = mod.getLoc();
 
     /*
      * Convert a buffer from UTF32 to UTF8
@@ -1413,7 +1414,7 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
 
         if (buf.length & 3)
         {
-            .error(mod.loc, "%s `%s` odd length of UTF-32 char source %llu",
+            .error(loc, "%s `%s` odd length of UTF-32 char source %llu",
                 mod.kind, mod.toPrettyChars, cast(ulong) buf.length);
             return null;
         }
@@ -1430,7 +1431,7 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
             {
                 if (u > 0x10FFFF)
                 {
-                    .error(mod.loc, "%s `%s` UTF-32 value %08x greater than 0x10FFFF", mod.kind, mod.toPrettyChars, u);
+                    .error(loc, "%s `%s` UTF-32 value %08x greater than 0x10FFFF", mod.kind, mod.toPrettyChars, u);
                     return null;
                 }
                 dbuf.writeUTF8(u);
@@ -1460,7 +1461,7 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
 
         if (buf.length & 1)
         {
-            .error(mod.loc, "%s `%s` odd length of UTF-16 char source %llu", mod.kind, mod.toPrettyChars, cast(ulong) buf.length);
+            .error(loc, "%s `%s` odd length of UTF-16 char source %llu", mod.kind, mod.toPrettyChars, cast(ulong) buf.length);
             return null;
         }
 
@@ -1480,13 +1481,13 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
                     i++;
                     if (i >= eBuf.length)
                     {
-                        .error(mod.loc, "%s `%s` surrogate UTF-16 high value %04x at end of file", mod.kind, mod.toPrettyChars, u);
+                        .error(loc, "%s `%s` surrogate UTF-16 high value %04x at end of file", mod.kind, mod.toPrettyChars, u);
                         return null;
                     }
                     const u2 = readNext(&eBuf[i]);
                     if (u2 < 0xDC00 || 0xE000 <= u2)
                     {
-                        .error(mod.loc, "%s `%s` surrogate UTF-16 low value %04x out of range", mod.kind, mod.toPrettyChars, u2);
+                        .error(loc, "%s `%s` surrogate UTF-16 low value %04x out of range", mod.kind, mod.toPrettyChars, u2);
                         return null;
                     }
                     u = (u - 0xD7C0) << 10;
@@ -1494,12 +1495,12 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
                 }
                 else if (u >= 0xDC00 && u <= 0xDFFF)
                 {
-                    .error(mod.loc, "%s `%s` unpaired surrogate UTF-16 value %04x", mod.kind, mod.toPrettyChars, u);
+                    .error(loc, "%s `%s` unpaired surrogate UTF-16 value %04x", mod.kind, mod.toPrettyChars, u);
                     return null;
                 }
                 else if (u == 0xFFFE || u == 0xFFFF)
                 {
-                    .error(mod.loc, "%s `%s` illegal UTF-16 value %04x", mod.kind, mod.toPrettyChars, u);
+                    .error(loc, "%s `%s` illegal UTF-16 value %04x", mod.kind, mod.toPrettyChars, u);
                     return null;
                 }
                 dbuf.writeUTF8(u);
@@ -1558,7 +1559,6 @@ private const(char)[] processSource (const(ubyte)[] src, Module mod)
     // It's UTF-8
     if (buf[0] >= 0x80)
     {
-        auto loc = mod.getLoc();
         .error(loc, "%s `%s` source file must start with BOM or ASCII character, not \\x%02X", mod.kind, mod.toPrettyChars, buf[0]);
         return null;
     }
diff --git a/compiler/src/dmd/expressionsem.d b/compiler/src/dmd/expressionsem.d
index b4d5274e7c..db40ae01de 100644
--- a/compiler/src/dmd/expressionsem.d
+++ b/compiler/src/dmd/expressionsem.d
@@ -12357,8 +12357,16 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             return result;
         }
 
-        void handleCatArgument(Expressions *arguments, Expression e)
+        void handleCatArgument(Expressions *arguments, Expression e, Type catType, bool isRightArg)
         {
+            auto tb = e.type.toBasetype();
+
+            if ((isRightArg && e.parens) || (!isRightArg && !tb.equals(catType)))
+            {
+                arguments.push(e);
+                return;
+            }
+
             if (auto ce = e.isCatExp())
             {
                 Expression lowering = ce.lowering;
@@ -12388,8 +12396,8 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             arguments.push(new StringExp(exp.loc, funcname.toDString()));
         }
 
-        handleCatArgument(arguments, exp.e1);
-        handleCatArgument(arguments, exp.e2);
+        handleCatArgument(arguments, exp.e1, exp.type.toBasetype(), false);
+        handleCatArgument(arguments, exp.e2, exp.type.toBasetype(), true);
 
         Expression id = new IdentifierExp(exp.loc, Id.empty);
         id = new DotIdExp(exp.loc, id, Id.object);
diff --git a/compiler/src/dmd/objc_glue.d b/compiler/src/dmd/objc_glue.d
index 1812470675..db17af93d6 100644
--- a/compiler/src/dmd/objc_glue.d
+++ b/compiler/src/dmd/objc_glue.d
@@ -338,7 +338,7 @@ struct Segments
         immutable(char*) sectionName;
         immutable(char*) segmentName;
         immutable int flags;
-        immutable int alignment;
+        immutable int p2align;
 
         this(typeof(this.tupleof) tuple) @safe
         {
@@ -388,7 +388,7 @@ struct Segments
             return segments[id] = Obj.getsegment(
                 seg.sectionName,
                 seg.segmentName,
-                seg.alignment,
+                seg.p2align,
                 seg.flags
             );
         }
@@ -1159,7 +1159,7 @@ private:
         const symbolName = prefix ~ classDeclaration.objc.identifier.toString();
         auto symbol = Symbols.getStatic(symbolName);
         symbol.Sseg = Segments[Segments.Id.const_];
-        symbol.Salignment = 3;
+        symbol.Salignment = 8;
         symbol.Sdt = dtb.finish();
 
         return symbol;
@@ -1311,7 +1311,7 @@ struct ProtocolDeclaration
             symbol.Sseg = Segments[Segments.Id.protolist];
             symbol.Sclass = SC.comdat;
             symbol.Sflags |= SFLhidden;
-            symbol.Salignment = 3;
+            symbol.Salignment = 8;
 
             auto dtb = DtBuilder(0);
             dtb.xoff(protocol, 0);
@@ -1326,7 +1326,7 @@ struct ProtocolDeclaration
         symbol.Sseg = Segments[Segments.Id.data];
         symbol.Sclass = SC.comdat;
         symbol.Sflags |= SFLhidden;
-        symbol.Salignment = 3;
+        symbol.Salignment = 8;
 
         auto dtb = DtBuilder(0);
         toDt(dtb);
@@ -1478,7 +1478,7 @@ private:
 
         symbol.Sdt = dtb.finish();
         symbol.Sseg = Segments[Segments.Id.const_];
-        symbol.Salignment = 3;
+        symbol.Salignment = 8;
 
         return symbol;
     }
@@ -1512,7 +1512,7 @@ private:
 
         symbol.Sdt = dtb.finish();
         symbol.Sseg = Segments[Segments.Id.const_];
-        symbol.Salignment = 3;
+        symbol.Salignment = 8;
 
         outdata(symbol);
 
@@ -1546,7 +1546,7 @@ private:
 
         symbol.Sdt = dtb.finish();
         symbol.Sseg = Segments[Segments.Id.const_];
-        symbol.Salignment = 3;
+        symbol.Salignment = 8;
 
         outdata(symbol);
 
diff --git a/compiler/src/dmd/todt.d b/compiler/src/dmd/todt.d
index 10df5c782d..a614fcdfd0 100644
--- a/compiler/src/dmd/todt.d
+++ b/compiler/src/dmd/todt.d
@@ -92,6 +92,11 @@ void Initializer_toDt(Initializer init, ref DtBuilder dtb, bool isCfile)
         if (tb.ty == Tvector)
             tb = (cast(TypeVector)tb).basetype;
 
+        if (ai.dim == 0 && tb.isZeroInit(ai.loc))
+        {
+            dtb.nzeros(cast(uint)ai.type.size());
+            return;
+        }
         Type tn = tb.nextOf().toBasetype();
 
         //printf("\tdim = %d\n", ai.dim);
diff --git a/compiler/test/compilable/issue24399.d b/compiler/test/compilable/issue24399.d
new file mode 100644
index 0000000000..ae3e7442f5
--- /dev/null
+++ b/compiler/test/compilable/issue24399.d
@@ -0,0 +1,9 @@
+// REQUIRED_ARGS: -main
+// LINK:
+template rt_options()
+{
+    __gshared string[] rt_options = [];
+    string[] rt_options_tls = [];
+}
+
+alias _ = rt_options!();
diff --git a/compiler/test/compilable/issue24409.d b/compiler/test/compilable/issue24409.d
new file mode 100644
index 0000000000..5d298df211
--- /dev/null
+++ b/compiler/test/compilable/issue24409.d
@@ -0,0 +1,17 @@
+static struct S
+{
+    union
+    {
+        int i;
+        long l;
+    }
+}
+
+int f()
+{
+    S* r = new S();
+    r.i = 5;
+    return r.i;
+}
+
+enum X = f();
diff --git a/compiler/test/fail_compilation/fail24422.c b/compiler/test/fail_compilation/fail24422.c
new file mode 100644
index 0000000000..d148b492c3
--- /dev/null
+++ b/compiler/test/fail_compilation/fail24422.c
@@ -0,0 +1,7 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/fail24422.c(7): Error: type-specifier missing for declaration of `a`
+---
+*/
+void f24422(a) a; { }
diff --git a/compiler/test/runnable/debug_info.d b/compiler/test/runnable/debug_info.d
deleted file mode 100644
index 7853d9a3d9..0000000000
--- a/compiler/test/runnable/debug_info.d
+++ /dev/null
@@ -1,50 +0,0 @@
-// REQUIRED_ARGS: -g
-
-void main()
-{
-    version(OSX) testDebugLineMacOS();
-}
-
-version (OSX):
-
-struct mach_header;
-struct mach_header_64;
-struct section;
-struct section_64;
-
-version (D_LP64)
-{
-    alias MachHeader = mach_header_64;
-    alias Section = section_64;
-}
-
-else
-{
-    alias MachHeader = mach_header;
-    alias Section = section;
-}
-
-extern (C)
-{
-    MachHeader* _dyld_get_image_header(uint image_index);
-    const(section)* getsectbynamefromheader(scope const mach_header* mhp, scope const char* segname, scope const char* sectname);
-    const(section_64)* getsectbynamefromheader_64(scope const mach_header_64* mhp, scope const char* segname, scope const char* sectname);
-}
-
-const(Section)* getSectByNameFromHeader(MachHeader* mhp, in char* segname, in char* sectname)
-{
-    version (D_LP64)
-        return getsectbynamefromheader_64(mhp, segname, sectname);
-    else
-        return getsectbynamefromheader(mhp, segname, sectname);
-}
-
-void testDebugLineMacOS()
-{
-    auto header = _dyld_get_image_header(0);
-    assert(header);
-
-    auto section = getSectByNameFromHeader(header, "__DWARF", "__debug_line");
-    // verify that the __debug_line section is present in the final executable
-    assert(section);
-}
diff --git a/compiler/test/runnable/extra-files/link20802a.d b/compiler/test/runnable/extra-files/link20802a.d
new file mode 100644
index 0000000000..3c52258ca4
--- /dev/null
+++ b/compiler/test/runnable/extra-files/link20802a.d
@@ -0,0 +1,8 @@
+import link20802b;
+void main()
+{
+     // First test from https://issues.dlang.org/show_bug.cgi?id=20802#c3
+     CodepointSet('a', 'z');
+     dstring s;
+     decodeGrapheme(s);
+}
diff --git a/compiler/test/runnable/extra-files/link20802b.d b/compiler/test/runnable/extra-files/link20802b.d
new file mode 100644
index 0000000000..333e8a29fc
--- /dev/null
+++ b/compiler/test/runnable/extra-files/link20802b.d
@@ -0,0 +1,30 @@
+module link20802b;
+
+// First test from https://issues.dlang.org/show_bug.cgi?id=20802#c3
+
+enum TransformRes { goOn }
+
+void writeAligned()()
+{
+    final switch (TransformRes.goOn) { case TransformRes.goOn: break; }
+}
+
+struct GcPolicy {}
+alias CodepointSet = InversionList!GcPolicy;
+struct InversionList(SP=GcPolicy)
+{
+    this()(uint[] intervals...)
+    {
+        sanitize();
+    }
+
+    void sanitize()
+    {
+        writeAligned();
+    }
+}
+
+void decodeGrapheme(Input)(ref Input inp)
+{
+    final switch (TransformRes.goOn) { case TransformRes.goOn: break; }
+}
diff --git a/compiler/test/runnable/issue24401.d b/compiler/test/runnable/issue24401.d
new file mode 100644
index 0000000000..109d543a0b
--- /dev/null
+++ b/compiler/test/runnable/issue24401.d
@@ -0,0 +1,6 @@
+// PERMUTE_ARGS:
+// https://issues.dlang.org/show_bug.cgi?id=24401
+int main()
+{
+    return (() @trusted => 0)();
+}
diff --git a/compiler/test/runnable/link20802.sh b/compiler/test/runnable/link20802.sh
new file mode 100755
index 0000000000..f0a6674fbf
--- /dev/null
+++ b/compiler/test/runnable/link20802.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+
+dir=${RESULTS_DIR}${SEP}runnable
+
+libname=${OUTPUT_BASE}${LIBEXT}
+exename=${OUTPUT_BASE}${EXE}
+
+$DMD -m${MODEL} -I${EXTRA_FILES} -lib -release -of${libname} ${EXTRA_FILES}${SEP}link20802b.d
+$DMD -m${MODEL} -I${EXTRA_FILES} -of${exename} ${EXTRA_FILES}${SEP}link20802a.d ${libname}
+
+${exename}
+
+rm_retry ${OUTPUT_BASE}{${LIBEXT},${EXE},${OBJ}}
diff --git a/compiler/test/runnable/test24371.d b/compiler/test/runnable/test24371.d
new file mode 100644
index 0000000000..885f9b8648
--- /dev/null
+++ b/compiler/test/runnable/test24371.d
@@ -0,0 +1,15 @@
+// https://issues.dlang.org/show_bug.cgi?id=24371
+
+void main()
+{
+    assert("b" ~ "c" == "bc");
+    assert(["a"] ~ "b" == ["a", "b"]);
+    assert(["a"] ~ ("b" ~ "c") == ["a", "bc"]);
+
+    auto strArr = ["a"];
+    assert(strArr ~ ("b" ~ "c") == ["a", "bc"]);
+    auto str = "c";
+    assert(["a"] ~ ("b" ~ str) == ["a", "bc"]);
+
+    assert(strArr ~ ("b" ~ str) == ["a", "bc"]);
+}
diff --git a/compiler/test/runnable_cxx/test7925.d b/compiler/test/runnable_cxx/test7925.d
index f05aac916e..2d0b023fe5 100644
--- a/compiler/test/runnable_cxx/test7925.d
+++ b/compiler/test/runnable_cxx/test7925.d
@@ -1,12 +1,5 @@
 // EXTRA_CPP_SOURCES: cpp7925.cpp
 
-/*
-Exclude -O/-inline due to a codegen bug on OSX:
-https://issues.dlang.org/show_bug.cgi?id=22556
-
-PERMUTE_ARGS(osx): -release -g
-*/
-
 import core.vararg;
 
 extern(C++) class C1
diff --git a/druntime/src/core/exception.d b/druntime/src/core/exception.d
index 959ce83f02..c7b302c452 100644
--- a/druntime/src/core/exception.d
+++ b/druntime/src/core/exception.d
@@ -19,6 +19,19 @@ void __switch_errorT()(string file = __FILE__, size_t line = __LINE__) @trusted
         assert(0, "No appropriate switch clause found");
 }
 
+/*
+ * Make sure template __switch_errorT is always instantiated when building
+ * druntime. This works around https://issues.dlang.org/show_bug.cgi?id=20802.
+ * When druntime and phobos are compiled with -release, the instance for
+ * __switch_errorT is not needed. An application compiled with -release
+ * could need the instance for __switch_errorT, but the compiler would
+ * not generate code for it, because it assumes, that it was already
+ * generated for druntime. Always including the instance in a compiled
+ * druntime allows to use an application without -release with druntime
+ * with -release.
+ */
+private alias dummy__switch_errorT = __switch_errorT!();
+
 /**
  * Thrown on a range error.
  */
diff --git a/druntime/test/exceptions/Makefile b/druntime/test/exceptions/Makefile
index fd975327d9..230013cc65 100644
--- a/druntime/test/exceptions/Makefile
+++ b/druntime/test/exceptions/Makefile
@@ -20,7 +20,7 @@ ifeq ($(OS)-$(BUILD),dragonflybsd-debug)
     LINE_TRACE_DFLAGS:=-L--export-dynamic
 endif
 ifeq ($(OS)-$(BUILD),osx-debug)
-    TESTS+=line_trace line_trace_21656 long_backtrace_trunc cpp_demangle
+    TESTS+=line_trace line_trace_21656 cpp_demangle
     LINE_TRACE_DFLAGS:=
 endif
 ifeq ($(OS)-$(BUILD),windows-debug)
@@ -42,7 +42,7 @@ $(ROOT)/line_trace.done: $(ROOT)/line_trace$(DOTEXE)
 	@echo Testing line_trace
 	$(QUIET)$(TIMELIMIT)$(ROOT)/line_trace $(RUN_ARGS) > $(ROOT)/line_trace.output
 	# Use sed to canonicalize line_trace.output and compare against expected output in line_trace.exp
-	$(QUIET)$(SED) "s/\[0x[0-9a-f]*\]/\[ADDR\]/g; s/scope //g; s/Nl//g" $(ROOT)/line_trace.output | $(DIFF) line_trace.exp -
+	$(QUIET)$(SED) "s|^.*/src/|src/|g; s/\[0x[0-9a-f]*\]/\[ADDR\]/g; s/scope //g; s/Nl//g" $(ROOT)/line_trace.output | $(DIFF) line_trace.exp -
 	@rm -f $(ROOT)/line_trace.output
 	@touch $@
 
@@ -52,7 +52,7 @@ $(ROOT)/line_trace_21656.done: $(ROOT)/line_trace$(DOTEXE)
 	@mkdir -p $(ROOT)/line_trace_21656
 	@touch $(ROOT)/line_trace_21656/line_trace
 	$(QUIET)cd $(ROOT)/line_trace_21656 && PATH="..:$$PATH" $(TIMELIMIT)line_trace $(RUN_ARGS) > line_trace.output
-	$(QUIET)$(SED) "s/\[0x[0-9a-f]*\]/\[ADDR\]/g; s/scope //g; s/Nl//g" $(ROOT)/line_trace_21656/line_trace.output | $(DIFF) line_trace.exp -
+	$(QUIET)$(SED) "s|^.*/src/|src/|g; s/\[0x[0-9a-f]*\]/\[ADDR\]/g; s/scope //g; s/Nl//g" $(ROOT)/line_trace_21656/line_trace.output | $(DIFF) line_trace.exp -
 	@rm -rf $(ROOT)/line_trace_21656
 	@touch $@
 
@@ -60,7 +60,7 @@ $(ROOT)/long_backtrace_trunc.done: $(ROOT)/long_backtrace_trunc$(DOTEXE)
 	@echo Testing long_backtrace_trunc
 	$(QUIET)$(TIMELIMIT)$(ROOT)/long_backtrace_trunc $(RUN_ARGS) > $(ROOT)/long_backtrace_trunc.output
 	# Use sed to canonicalize long_backtrace_trunc.output and compare against expected output in long_backtrace_trunc.exp
-	$(QUIET)$(SED) "s/\[0x[0-9a-f]*\]/\[ADDR\]/g; s/scope //g; s/Nl//g" $(ROOT)/long_backtrace_trunc.output | $(DIFF) long_backtrace_trunc.exp -
+	$(QUIET)$(SED) "s|^.*/src/|src/|g; s/\[0x[0-9a-f]*\]/\[ADDR\]/g; s/scope //g; s/Nl//g" $(ROOT)/long_backtrace_trunc.output | $(DIFF) long_backtrace_trunc.exp -
 	@rm -f $(ROOT)/long_backtrace_trunc.output
 	@touch $@