diff --git a/.gitignore b/.gitignore
index 45d8dbe..b6bb4f5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@
 zig-out
 .DS_Store
 .vscode/
-.sx-cache
\ No newline at end of file
+.sx-cache
+current/
\ No newline at end of file
diff --git a/examples/50-smoke.sx b/examples/50-smoke.sx
index b671a82..f6010a8 100644
--- a/examples/50-smoke.sx
+++ b/examples/50-smoke.sx
@@ -1,5 +1,6 @@
 #import "modules/std.sx";
 #import "modules/math/math.sx";
+#import "modules/compiler.sx";
 pkg :: #import "modules/testpkg";
 
 // ============================================================
@@ -3064,5 +3065,60 @@ END;
         print("opt-if5: {}\n", val2 ?? 0.0);
     }
 
+    // --- usize / isize ---
+    {
+        a : usize = 42;
+        b : isize = 0 - 7;
+        print("usize: {}\n", a);
+        print("isize: {}\n", b);
+
+        // arithmetic
+        c : usize = a + 8;
+        print("usize+8: {}\n", c);
+
+        // coercion from s32
+        x : s32 = 10;
+        y : usize = xx x;
+        print("s32->usize: {}\n", y);
+
+        // coercion to s64
+        z : s64 = xx a;
+        print("usize->s64: {}\n", z);
+    }
+
+    // --- inline if (compile-time conditionals) ---
+    print("=== inline if ===\n");
+    {
+        // POINTER_SIZE is 8 on desktop (64-bit)
+        inline if POINTER_SIZE == 8 {
+            print("64-bit\n");
+        } else {
+            print("32-bit\n");
+        }
+
+        // OS enum comparison
+        inline if OS == .wasm {
+            print("wasm\n");
+        } else {
+            print("not wasm\n");
+        }
+
+        // != comparison
+        inline if OS != .unknown {
+            print("known os\n");
+        } else {
+            print("unknown os\n");
+        }
+
+        // nested inline if
+        inline if POINTER_SIZE != 4 {
+            inline if OS != .wasm {
+                print("desktop 64-bit\n");
+            } else {
+                print("wasm 64-bit??\n");
+            }
+        }
+    }
+
     print("=== DONE ===\n");
 }
diff --git a/examples/modules/compiler.sx b/examples/modules/compiler.sx
new file mode 100644
index 0000000..80f831b
--- /dev/null
+++ b/examples/modules/compiler.sx
@@ -0,0 +1,6 @@
+OperatingSystem :: enum { macos; linux; windows; wasm; unknown; }
+Architecture :: enum { aarch64; x86_64; wasm32; unknown; }
+
+OS : OperatingSystem = .unknown;
+ARCH : Architecture = .unknown;
+POINTER_SIZE : s64 = 8;
diff --git a/examples/modules/opengl.sx b/examples/modules/opengl.sx
index e9acb27..2a4c368 100644
--- a/examples/modules/opengl.sx
+++ b/examples/modules/opengl.sx
@@ -49,11 +49,11 @@ glGenVertexArrays        : (s32, *u32) -> void = ---;
 glGenBuffers             : (s32, *u32) -> void = ---;
 glBindVertexArray        : (u32) -> void = ---;
 glBindBuffer             : (u32, u32) -> void = ---;
-glBufferData             : (u32, s64, *void, u32) -> void = ---;
+glBufferData             : (u32, isize, *void, u32) -> void = ---;
 glVertexAttribPointer    : (u32, s32, u32, u8, s32, *void) -> void = ---;
 glEnableVertexAttribArray : (u32) -> void = ---;
-glGetUniformLocation     : (u32, [:0]u8) -> s32 = ---;
-glUniformMatrix4fv       : (s32, s32, u8, [16]f32) -> void = ---;
+glGetUniformLocation     : (u32, [*]u8) -> s32 = ---;
+glUniformMatrix4fv       : (s32, s32, u8, [*]f32) -> void = ---;
 glUniform3f              : (s32, f32, f32, f32) -> void = ---;
 glDepthFunc              : (u32) -> void = ---;
 glUniform1f              : (s32, f32) -> void = ---;
@@ -72,10 +72,11 @@ GL_ONE_MINUS_SRC_ALPHA   :u32: 0x0303;
 GL_TEXTURE0              :u32: 0x84C0;
 GL_LINEAR                :u32: 0x2601;
 GL_RED                   :u32: 0x1903;
+GL_R8                    :u32: 0x8229;
 GL_UNPACK_ALIGNMENT      :u32: 0x0CF5;
 
 glScissor                : (s32, s32, s32, s32) -> void = ---;
-glBufferSubData          : (u32, s64, s64, *void) -> void = ---;
+glBufferSubData          : (u32, isize, isize, *void) -> void = ---;
 glGenTextures            : (s32, *u32) -> void = ---;
 glBindTexture            : (u32, u32) -> void = ---;
 glTexImage2D             : (u32, s32, s32, s32, s32, s32, u32, u32, *void) -> void = ---;
@@ -88,7 +89,7 @@ glPixelStorei            : (u32, s32) -> void = ---;
 
 // Loader: call once after creating GL context
 // Pass in a proc loader (e.g. SDL_GL_GetProcAddress)
-load_gl :: (get_proc: ([:0]u8) -> *void) {
+load_gl :: (get_proc: ([*]u8) -> *void) {
     glClearColor          = xx get_proc("glClearColor");
     glClear               = xx get_proc("glClear");
     glEnable              = xx get_proc("glEnable");
diff --git a/examples/modules/sdl3.sx b/examples/modules/sdl3.sx
index 77c0465..678031c 100644
--- a/examples/modules/sdl3.sx
+++ b/examples/modules/sdl3.sx
@@ -16,6 +16,7 @@ SDL_GL_CONTEXT_PROFILE_MASK  :s32: 20;
 
 // SDL_GLProfile
 SDL_GL_CONTEXT_PROFILE_CORE :s32: 0x1;
+SDL_GL_CONTEXT_PROFILE_ES   :s32: 0x4;
 
 // SDL_GLContextFlag
 SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG :s32: 0x2;
diff --git a/examples/modules/socket.sx b/examples/modules/socket.sx
index ebc0eab..29f3177 100644
--- a/examples/modules/socket.sx
+++ b/examples/modules/socket.sx
@@ -9,8 +9,8 @@ setsockopt :: (fd: s32, level: s32, optname: s32, optval: *s32, optlen: u32) ->
 bind       :: (fd: s32, addr: *SockAddr, addrlen: u32) -> s32 #foreign libc;
 listen     :: (fd: s32, backlog: s32) -> s32 #foreign libc;
 accept     :: (fd: s32, addr: *SockAddr, addrlen: *u32) -> s32 #foreign libc;
-read       :: (fd: s32, buf: [*]u8, count: s64) -> s64 #foreign libc;
-write      :: (fd: s32, buf: [*]u8, count: s64) -> s64 #foreign libc;
+read       :: (fd: s32, buf: [*]u8, count: usize) -> isize #foreign libc;
+write      :: (fd: s32, buf: [*]u8, count: usize) -> isize #foreign libc;
 close      :: (fd: s32) -> s32 #foreign libc;
 
 // Constants (macOS)
diff --git a/src/ast.zig b/src/ast.zig
index 26ef935..a4ddb9c 100644
--- a/src/ast.zig
+++ b/src/ast.zig
@@ -208,6 +208,7 @@ pub const IfExpr = struct {
     then_branch: *Node,
     else_branch: ?*Node,
     is_inline: bool, // true for `if cond then a else b`
+    is_comptime: bool = false, // true for `inline if` — compile-time branch elimination
     binding_name: ?[]const u8 = null, // for `if val := expr { ... }` optional binding
 };
 
diff --git a/src/c_import.zig b/src/c_import.zig
index 5edd010..04a13d4 100644
--- a/src/c_import.zig
+++ b/src/c_import.zig
@@ -303,6 +303,53 @@ pub fn loadCObjectsForJIT(
     };
 }
 
+/// Compile C sources using emcc for Emscripten/WASM targets.
+/// Shells out to `emcc -c` for each source file, returns temp object file paths.
+pub fn compileCWithEmcc(
+    allocator: std.mem.Allocator,
+    io: std.Io,
+    infos: []const CImportInfo,
+) ![]const []const u8 {
+    var paths = std.ArrayList([]const u8).empty;
+    var obj_idx: usize = 0;
+
+    for (infos) |info| {
+        if (info.sources.len == 0) continue;
+
+        for (info.sources) |src| {
+            const out_path = try std.fmt.allocPrint(allocator, "/tmp/sx_emcc_{d}.o", .{obj_idx});
+            obj_idx += 1;
+
+            var argv = std.ArrayList([]const u8).empty;
+            try argv.appendSlice(allocator, &.{ "emcc", "-c", "-O2", src, "-o", out_path });
+            // Add include paths
+            for (info.includes) |inc| {
+                try argv.append(allocator, try std.fmt.allocPrint(allocator, "-I{s}", .{dirName(inc)}));
+            }
+            for (info.defines) |def| {
+                try argv.append(allocator, try std.fmt.allocPrint(allocator, "-D{s}", .{def}));
+            }
+            for (info.flags) |flag| {
+                try argv.append(allocator, flag);
+            }
+
+            const argv_slice = try argv.toOwnedSlice(allocator);
+            var child = std.process.spawn(io, .{ .argv = argv_slice }) catch {
+                std.debug.print("error: failed to spawn emcc for '{s}'\n", .{src});
+                return error.CompileError;
+            };
+            const result = child.wait(io) catch return error.CompileError;
+            if (result != .exited or result.exited != 0) {
+                std.debug.print("error: emcc failed for '{s}'\n", .{src});
+                return error.CompileError;
+            }
+            try paths.append(allocator, out_path);
+        }
+    }
+
+    return try paths.toOwnedSlice(allocator);
+}
+
 /// For build mode: write .o buffers to temp files, return paths for the linker.
 pub fn writeCObjectFiles(
     allocator: std.mem.Allocator,
diff --git a/src/core.zig b/src/core.zig
index fb67b2e..d96680c 100644
--- a/src/core.zig
+++ b/src/core.zig
@@ -116,9 +116,14 @@ pub const Compilation = struct {
     pub fn lowerToIR(self: *Compilation) ir.Module {
         const root = self.resolved_root orelse self.root orelse return ir.Module.init(self.allocator);
         var module = ir.Module.init(self.allocator);
+        //TODO: find a better place for this
+        if (self.target_config.isWasm()) {
+            module.types.pointer_size = 4;
+        }
         var lowering = ir.Lowering.init(&module);
         lowering.main_file = self.file_path;
         lowering.resolved_root = root;
+        lowering.target_config = self.target_config;
         lowering.lowerRoot(root);
         return module;
     }
diff --git a/src/ir/emit_llvm.zig b/src/ir/emit_llvm.zig
index e0585a6..0335e91 100644
--- a/src/ir/emit_llvm.zig
+++ b/src/ir/emit_llvm.zig
@@ -2103,8 +2103,9 @@ pub const LLVMEmitter = struct {
         }
 
         // int→int: SExt, ZExt, or Trunc
-        const from_bits = intBits(from);
-        const to_bits = intBits(to);
+        const ptr_bits: u32 = @as(u32, self.ir_mod.types.pointer_size) * 8;
+        const from_bits = if (intBits(from) == 0) ptr_bits else intBits(from);
+        const to_bits = if (intBits(to) == 0) ptr_bits else intBits(to);
         if (to_bits > from_bits) {
             return if (isSignedType(from))
                 c.LLVMBuildSExt(self.builder, operand, to_ty, "sext")
@@ -2539,6 +2540,7 @@ pub const LLVMEmitter = struct {
             .string => self.getStringStructType(),
             .any => self.getAnyStructType(),
             .noreturn => self.cached_void,
+            .isize, .usize => if (self.target_config.isWasm()) self.cached_i32 else self.cached_i64,
             else => self.toLLVMTypeInfo(ty),
         };
     }
@@ -2665,6 +2667,7 @@ pub const LLVMEmitter = struct {
                 // For now, use opaque ptr
                 return self.cached_ptr;
             },
+            .usize, .isize => if (self.target_config.isWasm()) self.cached_i32 else self.cached_i64,
         };
     }
 
@@ -2684,12 +2687,11 @@ pub const LLVMEmitter = struct {
             if (info == .slice) return self.cached_ptr;
         }
 
-        // WASM32: i64 → i32 for C ABI (size_t/ssize_t are 32-bit on wasm32)
+        // WASM32: usize/isize are pointer-sized (i32 on wasm32).
+        // Other integer types (s64, u64) keep their declared size — they represent
+        // genuinely 64-bit values (SDL_WindowFlags, timestamps, etc.).
         if (self.target_config.isWasm()) {
-            if (c.LLVMGetTypeKind(llvm_ty) == c.LLVMIntegerTypeKind and c.LLVMGetIntTypeWidth(llvm_ty) == 64) {
-                // s64/u64 in extern decls → i32 on wasm32 (matches C's size_t, ssize_t, etc.)
-                return self.cached_i32;
-            }
+            if (ir_ty == .usize or ir_ty == .isize) return self.cached_i32;
             return llvm_ty;
         }
 
@@ -3075,7 +3077,7 @@ fn isFloatOrVecFloat(ty: TypeId, types: *const TypeTable) bool {
 
 fn isSignedType(ty: TypeId) bool {
     return switch (ty) {
-        .s8, .s16, .s32, .s64 => true,
+        .s8, .s16, .s32, .s64, .isize => true,
         else => false,
     };
 }
@@ -3095,6 +3097,7 @@ fn intBits(ty: TypeId) u32 {
         .s32, .u32 => 32,
         .s64, .u64 => 64,
         .bool => 1,
+        .usize, .isize => 0, // target-dependent — caller must query pointer_size
         else => 64,
     };
 }
diff --git a/src/ir/lower.zig b/src/ir/lower.zig
index b3f6d61..fb4a207 100644
--- a/src/ir/lower.zig
+++ b/src/ir/lower.zig
@@ -104,6 +104,13 @@ pub const Lowering = struct {
     foreign_name_map: std.StringHashMap([]const u8) = std.StringHashMap([]const u8).init(std.heap.page_allocator), // sx name → C name for #foreign renames
     type_alias_map: std.StringHashMap(TypeId) = std.StringHashMap(TypeId).init(std.heap.page_allocator), // type alias name → target TypeId
     ufcs_alias_map: std.StringHashMap([]const u8) = std.StringHashMap([]const u8).init(std.heap.page_allocator), // UFCS alias name → target function name
+    target_config: ?@import("../target.zig").TargetConfig = null, // compilation target (for inline if)
+    comptime_constants: std.StringHashMap(ComptimeValue) = std.StringHashMap(ComptimeValue).init(std.heap.page_allocator), // compile-time known constants (e.g. OS, ARCH)
+
+    pub const ComptimeValue = union(enum) {
+        int_val: i64,
+        enum_tag: struct { ty: TypeId, tag: u32 },
+    };
 
     const StructConstInfo = struct {
         value: *const Node,
@@ -165,12 +172,68 @@ pub const Lowering = struct {
         };
         // Pass 1: scan — register all function ASTs, struct types, extern stubs
         self.scanDecls(decls);
+        // Pass 1b: inject compile-time constants (OS, ARCH, POINTER_SIZE) from target config
+        self.injectComptimeConstants();
         // Pass 2: lower main (and comptime side-effects)
         self.lowerMainAndComptime(decls);
         // Pass 3: lower deferred functions (any_to_string etc.) now that all types are registered
         self.lowerDeferredTypeFns();
     }
 
+    /// Inject compile-time constants from target_config into comptime_constants.
+    /// Called after scanDecls so that enum types (OperatingSystem, Architecture) are registered.
+    fn injectComptimeConstants(self: *Lowering) void {
+        const tc = self.target_config orelse return;
+
+        // OS: OperatingSystem enum { macos; linux; windows; wasm; unknown; }
+        const os_name_id = self.module.types.internString("OperatingSystem");
+        if (self.module.types.findByName(os_name_id)) |os_ty| {
+            const os_info = self.module.types.get(os_ty);
+            if (os_info == .@"enum") {
+                const tag: u32 = if (tc.isWasm())
+                    self.findVariantIndex(os_info.@"enum".variants, "wasm")
+                else if (tc.isWindows())
+                    self.findVariantIndex(os_info.@"enum".variants, "windows")
+                else if (tc.isLinux())
+                    self.findVariantIndex(os_info.@"enum".variants, "linux")
+                else if (tc.isMacOS())
+                    self.findVariantIndex(os_info.@"enum".variants, "macos")
+                else
+                    self.findVariantIndex(os_info.@"enum".variants, "unknown");
+                self.comptime_constants.put("OS", .{ .enum_tag = .{ .ty = os_ty, .tag = tag } }) catch {};
+            }
+        }
+
+        // ARCH: Architecture enum { aarch64; x86_64; wasm32; unknown; }
+        const arch_name_id = self.module.types.internString("Architecture");
+        if (self.module.types.findByName(arch_name_id)) |arch_ty| {
+            const arch_info = self.module.types.get(arch_ty);
+            if (arch_info == .@"enum") {
+                const tag: u32 = if (tc.isWasm())
+                    self.findVariantIndex(arch_info.@"enum".variants, "wasm32")
+                else if (tc.isAarch64())
+                    self.findVariantIndex(arch_info.@"enum".variants, "aarch64")
+                else if (tc.isX86_64())
+                    self.findVariantIndex(arch_info.@"enum".variants, "x86_64")
+                else
+                    self.findVariantIndex(arch_info.@"enum".variants, "unknown");
+                self.comptime_constants.put("ARCH", .{ .enum_tag = .{ .ty = arch_ty, .tag = tag } }) catch {};
+            }
+        }
+
+        // POINTER_SIZE: s64 (4 for wasm, 8 otherwise)
+        const ptr_size: i64 = if (tc.isWasm()) 4 else 8;
+        self.comptime_constants.put("POINTER_SIZE", .{ .int_val = ptr_size }) catch {};
+    }
+
+    fn findVariantIndex(self: *Lowering, variants: []const types.StringId, name: []const u8) u32 {
+        const name_id = self.module.types.internString(name);
+        for (variants, 0..) |v, i| {
+            if (v == name_id) return @intCast(i);
+        }
+        return 0; // fallback to first variant
+    }
+
     /// Lower functions that were deferred because they use type-category matching.
     /// At this point, main is fully lowered and all types are in the TypeTable.
     fn lowerDeferredTypeFns(self: *Lowering) void {
@@ -381,6 +444,8 @@ pub const Lowering = struct {
                     const init_val: ?inst_mod.ConstantValue = if (vd.value) |v| switch (v.data) {
                         .undef_literal => .zeroinit,
                         .int_literal => |il| .{ .int = il.value },
+                        .bool_literal => |bl| .{ .boolean = bl.value },
+                        .float_literal => |fl| .{ .float = fl.value },
                         .string_literal => |sl| .{ .string = self.module.types.internString(sl.raw) },
                         else => null,
                     } else null;
@@ -723,6 +788,15 @@ pub const Lowering = struct {
         }
     }
 
+    /// Lower an `inline if` branch — block body emits statements, expression returns value.
+    fn lowerInlineBranch(self: *Lowering, node: *const Node) Ref {
+        if (node.data == .block) {
+            self.lowerBlock(node);
+            return self.builder.constInt(0, .void);
+        }
+        return self.lowerExpr(node);
+    }
+
     /// Lower a block and return the last expression's value (for implicit returns).
     fn lowerBlockValue(self: *Lowering, node: *const Node) ?Ref {
         // Set force_block_value so nested if-else expressions produce values
@@ -1845,6 +1919,19 @@ pub const Lowering = struct {
     // ── Control flow ────────────────────────────────────────────────
 
     fn lowerIfExpr(self: *Lowering, ie: *const ast.IfExpr) Ref {
+        // inline if: evaluate condition at compile time, only lower taken branch
+        if (ie.is_comptime) {
+            if (self.evalComptimeCondition(ie.condition)) |is_true| {
+                if (is_true) {
+                    return self.lowerInlineBranch(ie.then_branch);
+                } else if (ie.else_branch) |eb| {
+                    return self.lowerInlineBranch(eb);
+                }
+                return self.builder.constInt(0, .void);
+            }
+            // Condition couldn't be evaluated — fall through to runtime
+        }
+
         // Check for constant-bool conditions (e.g., is_flags(T) → false) to avoid dead-code LLVM errors
         if (self.tryConstBoolCondition(ie.condition)) |is_true| {
             if (is_true) {
@@ -1999,6 +2086,46 @@ pub const Lowering = struct {
         return null;
     }
 
+    /// Evaluate a compile-time condition for `inline if`.
+    /// Handles: `ident == .variant`, `ident != .variant`, `ident == int`, `ident != int`.
+    fn evalComptimeCondition(self: *Lowering, node: *const Node) ?bool {
+        if (node.data != .binary_op) return null;
+        const bo = &node.data.binary_op;
+        if (bo.op != .eq and bo.op != .neq) return null;
+
+        // LHS must be an identifier that's in comptime_constants
+        const name = switch (bo.lhs.data) {
+            .identifier => |id| id.name,
+            else => return null,
+        };
+        const cv = self.comptime_constants.get(name) orelse return null;
+
+        switch (cv) {
+            .enum_tag => |et| {
+                // RHS must be an enum literal (.variant)
+                const variant_name = switch (bo.rhs.data) {
+                    .enum_literal => |el| el.name,
+                    else => return null,
+                };
+                // Look up variant index in the enum type
+                const enum_info = self.module.types.get(et.ty);
+                if (enum_info != .@"enum") return null;
+                const variant_idx = self.findVariantIndex(enum_info.@"enum".variants, variant_name);
+                const result = et.tag == variant_idx;
+                return if (bo.op == .eq) result else !result;
+            },
+            .int_val => |iv| {
+                // RHS must be an integer literal
+                const rhs_val: i64 = switch (bo.rhs.data) {
+                    .int_literal => |il| il.value,
+                    else => return null,
+                };
+                const result = iv == rhs_val;
+                return if (bo.op == .eq) result else !result;
+            },
+        }
+    }
+
     fn lowerWhile(self: *Lowering, we: *const ast.WhileExpr) Ref {
         const header_bb = self.freshBlock("while.hdr");
         const body_bb = self.freshBlock("while.body");
@@ -2857,6 +2984,10 @@ pub const Lowering = struct {
             const info = self.module.types.get(obj_ty);
             switch (info) {
                 .tagged_union => |u| {
+                    // .tag → extract the enum tag value with the correct tag type
+                    if (std.mem.eql(u8, field, "tag")) {
+                        return self.builder.emit(.{ .enum_tag = .{ .operand = obj } }, u.tag_type);
+                    }
                     // Tagged union — use enum_payload
                     for (u.fields, 0..) |f, i| {
                         if (f.name == field_name_id) {
@@ -3727,8 +3858,19 @@ pub const Lowering = struct {
                 }
 
                 // Method call: obj.method(args) → prepend obj (or &obj for *Self receivers)
-                const obj_ty = self.inferExprType(fa.object);
-                const obj = self.lowerExpr(fa.object);
+                // For ptr.*.method(): pass the pointer directly instead of loading + re-addressing.
+                // This ensures mutations through self: *T are visible after the call.
+                var obj_ty: TypeId = undefined;
+                var obj: Ref = undefined;
+                var effective_obj_node: *const Node = fa.object;
+                if (fa.object.data == .deref_expr) {
+                    effective_obj_node = fa.object.data.deref_expr.operand;
+                    obj_ty = self.inferExprType(effective_obj_node);
+                    obj = self.lowerExpr(effective_obj_node);
+                } else {
+                    obj_ty = self.inferExprType(fa.object);
+                    obj = self.lowerExpr(fa.object);
+                }
 
                 // Check if field is a closure type — call as closure, not method
                 if (!obj_ty.isBuiltin()) {
@@ -3781,7 +3923,7 @@ pub const Lowering = struct {
                                     const func = &self.module.functions.items[@intFromEnum(fid)];
                                     const ret_ty = func.ret;
                                     const params = func.params;
-                                    self.fixupMethodReceiver(&method_args, func, fa.object, obj_ty);
+                                    self.fixupMethodReceiver(&method_args, func, effective_obj_node, obj_ty);
                                     self.coerceCallArgs(method_args.items, params);
                                     return self.builder.call(fid, method_args.items, ret_ty);
                                 }
@@ -3800,7 +3942,7 @@ pub const Lowering = struct {
                         const func = &self.module.functions.items[@intFromEnum(fid)];
                         const ret_ty = func.ret;
                         const params = func.params;
-                        self.fixupMethodReceiver(&method_args, func, fa.object, obj_ty);
+                        self.fixupMethodReceiver(&method_args, func, effective_obj_node, obj_ty);
                         // Note: coerceCallArgs can trigger protocol thunk creation
                         // (module.addFunction), invalidating func pointer.
                         // Use pre-extracted params/ret_ty instead of func.* after this.
@@ -4005,6 +4147,14 @@ pub const Lowering = struct {
             if (!tt.isBuiltin()) {
                 const tti = self.module.types.get(tt);
                 if (tti == .closure) break :blk tti.closure.params;
+                // Unwrap ?Closure(...) → Closure(...)
+                if (tti == .optional) {
+                    const inner = tti.optional.child;
+                    if (!inner.isBuiltin()) {
+                        const inner_info = self.module.types.get(inner);
+                        if (inner_info == .closure) break :blk inner_info.closure.params;
+                    }
+                }
             }
             break :blk null;
         } else null;
@@ -4031,6 +4181,14 @@ pub const Lowering = struct {
                 if (!tt.isBuiltin()) {
                     const tti = self.module.types.get(tt);
                     if (tti == .closure) break :blk tti.closure.ret;
+                    // Unwrap ?Closure(...) → Closure(...)
+                    if (tti == .optional) {
+                        const inner = tti.optional.child;
+                        if (!inner.isBuiltin()) {
+                            const inner_info = self.module.types.get(inner);
+                            if (inner_info == .closure) break :blk inner_info.closure.ret;
+                        }
+                    }
                 }
             }
             // Arrow lambda without explicit return type — infer from body expression
@@ -4388,8 +4546,7 @@ pub const Lowering = struct {
             offset = (offset + field_align - 1) & ~(field_align - 1);
             offset += field_size;
         }
-        // Align total to struct alignment (max field alignment, minimum 8)
-        if (max_align < 8) max_align = 8;
+        // Align total to max field alignment (matches LLVM's struct alignment)
         return (offset + max_align - 1) & ~(max_align - 1);
     }
 
@@ -5716,6 +5873,8 @@ pub const Lowering = struct {
         if (ty == .void) return "void";
         if (ty == .string) return "string";
         if (ty == .any) return "Any";
+        if (ty == .usize) return "usize";
+        if (ty == .isize) return "isize";
 
         const info = self.module.types.get(ty);
         return switch (info) {
@@ -5880,6 +6039,8 @@ pub const Lowering = struct {
         if (ty == .void) return "void";
         if (ty == .string) return "string";
         if (ty == .any) return "Any";
+        if (ty == .usize) return "usize";
+        if (ty == .isize) return "isize";
 
         const info = self.module.types.get(ty);
         return switch (info) {
@@ -5932,6 +6093,8 @@ pub const Lowering = struct {
             tags.append(self.alloc, TypeId.u16.index()) catch {};
             tags.append(self.alloc, TypeId.u32.index()) catch {};
             tags.append(self.alloc, TypeId.u64.index()) catch {};
+            tags.append(self.alloc, TypeId.usize.index()) catch {};
+            tags.append(self.alloc, TypeId.isize.index()) catch {};
             return tags.items;
         }
         if (std.mem.eql(u8, name, "float")) {
@@ -7220,6 +7383,7 @@ pub const Lowering = struct {
         // Build call args: ctx + user args
         // Protocol method params use *void for Self-typed params. If the caller passes
         // a struct value, we need to alloca+store and pass the pointer instead.
+        // Also coerce argument types to match declared param types (e.g., s64 → s32).
         var call_args = std.ArrayList(Ref).empty;
         defer call_args.deinit(self.alloc);
         call_args.append(self.alloc, ctx) catch unreachable;
@@ -7233,7 +7397,9 @@ pub const Lowering = struct {
                 self.builder.store(slot, a);
                 call_args.append(self.alloc, slot) catch unreachable;
             } else {
-                call_args.append(self.alloc, a) catch unreachable;
+                // Coerce to match declared parameter type (critical for WASM strict signatures)
+                const coerced = self.coerceToType(a, arg_ty, expected_ty);
+                call_args.append(self.alloc, coerced) catch unreachable;
             }
         }
         const owned = self.alloc.dupe(Ref, call_args.items) catch unreachable;
@@ -8010,7 +8176,7 @@ pub const Lowering = struct {
 
     fn isInt(ty: TypeId) bool {
         return switch (ty) {
-            .s8, .s16, .s32, .s64, .u8, .u16, .u32, .u64 => true,
+            .s8, .s16, .s32, .s64, .u8, .u16, .u32, .u64, .usize, .isize => true,
             else => false,
         };
     }
@@ -8034,6 +8200,7 @@ pub const Lowering = struct {
             .s16, .u16 => 16,
             .s32, .u32 => 32,
             .s64, .u64 => 64,
+            .usize, .isize => 0, // target-dependent — use typeBitsEx
             .f32 => 32,
             .f64 => 64,
             else => 0,
@@ -8041,6 +8208,7 @@ pub const Lowering = struct {
     }
 
     fn typeBitsEx(self: *Lowering, ty: TypeId) u32 {
+        if (ty == .usize or ty == .isize) return @as(u32, self.module.types.pointer_size) * 8;
         const b = typeBits(ty);
         if (b > 0) return b;
         if (!ty.isBuiltin()) {
diff --git a/src/ir/type_bridge.zig b/src/ir/type_bridge.zig
index 94e498c..5d6db8f 100644
--- a/src/ir/type_bridge.zig
+++ b/src/ir/type_bridge.zig
@@ -65,6 +65,8 @@ pub fn bridgeType(ty: sx_types.Type, table: *TypeTable) TypeId {
         .boolean => .bool,
         .string_type => .string,
         .any_type => .any,
+        .usize_type => .usize,
+        .isize_type => .isize,
         .enum_type => |name| resolveNamedType(name, .@"enum", table),
         .struct_type => |name| resolveNamedType(name, .@"struct", table),
         .union_type => |name| resolveNamedType(name, .@"union", table),
@@ -222,6 +224,8 @@ pub fn resolveTypePrimitive(name: []const u8) ?TypeId {
     if (std.mem.eql(u8, name, "Any")) return .any;
     if (std.mem.eql(u8, name, "Type")) return .any; // Type-as-value: boxed string
     if (std.mem.eql(u8, name, "noreturn")) return .noreturn;
+    if (std.mem.eql(u8, name, "usize")) return .usize;
+    if (std.mem.eql(u8, name, "isize")) return .isize;
     return null;
 }
 
diff --git a/src/ir/types.zig b/src/ir/types.zig
index 9cf4f62..586827f 100644
--- a/src/ir/types.zig
+++ b/src/ir/types.zig
@@ -21,10 +21,11 @@ pub const TypeId = enum(u32) {
     string = 12, // [:0]u8
     any = 13,
     noreturn = 14,
-    _reserved = 15,
-    _, // user-defined types start at 16
+    isize = 15,
+    usize = 16,
+    _, // user-defined types start at 17
 
-    pub const first_user: u32 = 16;
+    pub const first_user: u32 = 17;
 
     pub fn index(self: TypeId) u32 {
         return @intFromEnum(self);
@@ -69,6 +70,8 @@ pub const TypeInfo = union(enum) {
     any,
     protocol: ProtocolInfo,
     noreturn,
+    usize,
+    isize,
 
     pub const StructInfo = struct {
         name: StringId,
@@ -225,6 +228,8 @@ pub const TypeTable = struct {
     /// Maps TypeInfo → TypeId for dedup of structural types
     intern_map: std.HashMap(TypeKey, TypeId, TypeKeyContext, 80),
     alloc: Allocator,
+    /// Target pointer size in bytes (4 for wasm32, 8 for 64-bit targets).
+    pointer_size: u8 = 8,
 
     pub fn init(alloc: Allocator) TypeTable {
         var table = TypeTable{
@@ -251,7 +256,8 @@ pub const TypeTable = struct {
             .string, // 12
             .any, // 13
             .noreturn, // 14
-            .void, // 15: reserved (placeholder)
+            .isize, // 15: isize (pointer-sized signed)
+            .usize, // 16: usize (pointer-sized unsigned)
         };
         for (&builtins) |info| {
             table.infos.append(alloc, info) catch unreachable;
@@ -402,25 +408,27 @@ pub const TypeTable = struct {
     /// This is the authoritative size computation used for closure env sizing and
     /// verified against LLVMABISizeOfType.
     pub fn typeSizeBytes(self: *const TypeTable, ty: TypeId) usize {
+        const ptr_size: usize = self.pointer_size;
         if (ty == .void) return 0;
         if (ty == .bool) return 1;
         if (ty == .u8 or ty == .s8) return 1;
         if (ty == .u16 or ty == .s16) return 2;
         if (ty == .s32 or ty == .u32 or ty == .f32) return 4;
         if (ty == .s64 or ty == .u64 or ty == .f64) return 8;
-        if (ty == .string) return 16; // {ptr, i64}
-        if (ty.isBuiltin()) return 8; // default for unknown builtins
+        if (ty == .usize or ty == .isize) return ptr_size;
+        if (ty == .string) return 16; // {ptr, i64} — always 16 (i64 alignment pads on wasm32)
+        if (ty.isBuiltin()) return ptr_size; // default for unknown builtins
         const info = self.get(ty);
         return switch (info) {
-            .pointer, .many_pointer, .function => 8,
-            .slice => 16, // {ptr, i64}
-            .closure => 16, // {fn_ptr, env_ptr}
+            .pointer, .many_pointer, .function => ptr_size,
+            .slice => 16, // {ptr, i64} — same layout as string
+            .closure => 2 * ptr_size, // {fn_ptr, env_ptr}
             .optional => |o| blk: {
                 const child_info = self.get(o.child);
                 if (child_info == .pointer or child_info == .many_pointer or child_info == .function)
-                    break :blk 8;
+                    break :blk ptr_size;
                 if (child_info == .closure)
-                    break :blk 16; // {fn_ptr, env_ptr}
+                    break :blk 2 * ptr_size;
                 const cs = self.typeSizeBytes(o.child);
                 const ca = self.typeAlignBytes(o.child);
                 // { T, i1 } — i1 goes right after T, then pad to struct alignment
@@ -480,8 +488,8 @@ pub const TypeTable = struct {
                 }
                 break :blk if (offset == 0) 0 else (offset + max_a - 1) & ~(max_a - 1);
             },
-            .any => 16,
-            .protocol => 16,
+            .any => 2 * ptr_size, // {type_tag, data_ptr}
+            .protocol => 2 * ptr_size, // {ctx, vtable}
             .@"enum" => |e| {
                 if (e.backing_type) |bt| return self.typeSizeBytes(bt);
                 return 8;
@@ -492,22 +500,25 @@ pub const TypeTable = struct {
 
     /// Compute the ABI alignment in bytes for a type, matching LLVM's rules.
     pub fn typeAlignBytes(self: *const TypeTable, ty: TypeId) usize {
+        const ptr_align: usize = self.pointer_size;
         if (ty == .void) return 1;
         if (ty == .bool) return 1;
         if (ty == .u8 or ty == .s8) return 1;
         if (ty == .u16 or ty == .s16) return 2;
         if (ty == .s32 or ty == .u32 or ty == .f32) return 4;
         if (ty == .s64 or ty == .u64 or ty == .f64) return 8;
-        if (ty == .string) return 8;
-        if (ty.isBuiltin()) return 8;
+        if (ty == .usize or ty == .isize) return ptr_align;
+        if (ty == .string) return 8; // i64 drives alignment
+        if (ty.isBuiltin()) return ptr_align;
         const info = self.get(ty);
         return switch (info) {
-            .pointer, .many_pointer, .function => 8,
-            .slice, .closure => 8,
+            .pointer, .many_pointer, .function => ptr_align,
+            .slice => 8, // i64 drives alignment
+            .closure => ptr_align, // {ptr, ptr}
             .optional => |o| blk: {
                 const child_info = self.get(o.child);
                 if (child_info == .pointer or child_info == .many_pointer or child_info == .function or child_info == .closure)
-                    break :blk 8;
+                    break :blk ptr_align;
                 break :blk self.typeAlignBytes(o.child);
             },
             .@"struct" => |s| blk: {
@@ -566,6 +577,8 @@ pub const TypeTable = struct {
             .string => "string",
             .any => "Any",
             .noreturn => "noreturn",
+            .isize => "isize",
+            .usize => "usize",
             else => {
                 // User types — format from TypeInfo
                 const info = self.get(id);
@@ -609,7 +622,7 @@ fn hashTypeInfo(h: *std.hash.Wyhash, info: TypeInfo) void {
     switch (info) {
         .signed => |w| h.update(&.{w}),
         .unsigned => |w| h.update(&.{w}),
-        .f32, .f64, .void, .bool, .string, .any, .noreturn => {},
+        .f32, .f64, .void, .bool, .string, .any, .noreturn, .usize, .isize => {},
         .pointer => |p| h.update(std.mem.asBytes(&p.pointee)),
         .many_pointer => |p| h.update(std.mem.asBytes(&p.element)),
         .slice => |s| h.update(std.mem.asBytes(&s.element)),
@@ -650,7 +663,7 @@ fn typeInfoEql(a: TypeInfo, b: TypeInfo) bool {
     return switch (a) {
         .signed => |w| w == b.signed,
         .unsigned => |w| w == b.unsigned,
-        .f32, .f64, .void, .bool, .string, .any, .noreturn => true,
+        .f32, .f64, .void, .bool, .string, .any, .noreturn, .usize, .isize => true,
         .pointer => |p| p.pointee == b.pointer.pointee,
         .many_pointer => |p| p.element == b.many_pointer.element,
         .slice => |s| s.element == b.slice.element,
diff --git a/src/lsp/server.zig b/src/lsp/server.zig
index 4f77bcb..ee10b77 100644
--- a/src/lsp/server.zig
+++ b/src/lsp/server.zig
@@ -1477,6 +1477,7 @@ pub const Server = struct {
             .kw_closure,
             .kw_protocol,
             .kw_impl,
+            .kw_inline,
             .hash_run,
             .hash_import,
             .hash_insert,
diff --git a/src/main.zig b/src/main.zig
index d9943a3..3f31d67 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -223,6 +223,11 @@ fn compileCForBuild(allocator: std.mem.Allocator, io: std.Io, comp: *sx.core.Com
     const c_infos = try comp.collectCImportSources();
     if (c_infos.len == 0) return &.{};
 
+    // For Emscripten targets, use emcc to cross-compile C sources
+    if (comp.target_config.isEmscripten()) {
+        return try sx.c_import.compileCWithEmcc(allocator, io, c_infos);
+    }
+
     const obj_bufs = try sx.c_import.compileCToObjects(allocator, c_infos);
     return try sx.c_import.writeCObjectFiles(allocator, io, obj_bufs);
 }
diff --git a/src/parser.zig b/src/parser.zig
index 8d8a3c8..4addeda 100644
--- a/src/parser.zig
+++ b/src/parser.zig
@@ -82,6 +82,18 @@ pub const Parser = struct {
             return self.parseImplBlock(start);
         }
 
+        // Top-level `inline if` — compile-time conditional
+        if (self.current.tag == .kw_inline) {
+            if (self.peekNext() == .kw_if) {
+                self.advance(); // skip 'inline'
+                const expr = try self.parseIfExpr();
+                if (expr.data == .if_expr) {
+                    expr.data.if_expr.is_comptime = true;
+                }
+                return expr;
+            }
+        }
+
         // All top-level declarations start with an identifier
         if (!self.isIdentLike() and self.current.tag != .kw_Self) {
             return self.fail("expected identifier at top level");
@@ -1375,6 +1387,19 @@ pub const Parser = struct {
             return try self.createNode(start, .{ .insert_expr = .{ .expr = inner } });
         }
 
+        // inline if — compile-time conditional
+        if (self.current.tag == .kw_inline) {
+            if (self.peekNext() == .kw_if) {
+                self.advance(); // skip 'inline'
+                const expr = try self.parseIfExpr();
+                if (expr.data == .if_expr) {
+                    expr.data.if_expr.is_comptime = true;
+                }
+                try self.expectSemicolonAfter(expr);
+                return expr;
+            }
+        }
+
         // Block-form if/while/for as statements — parse directly to prevent
         // postfix chaining (e.g. `if cond { ... }.field` being misparsed)
         if (self.current.tag == .kw_if) {
diff --git a/src/target.zig b/src/target.zig
index dedf528..f5f14f8 100644
--- a/src/target.zig
+++ b/src/target.zig
@@ -58,6 +58,16 @@ pub const TargetConfig = struct {
         return self.tripleHasPrefix("wasm32", "wasm64");
     }
 
+    /// Check if target triple indicates macOS/Darwin.
+    pub fn isMacOS(self: TargetConfig) bool {
+        return self.tripleContains("darwin") or self.tripleContains("macos");
+    }
+
+    /// Check if target triple indicates Linux.
+    pub fn isLinux(self: TargetConfig) bool {
+        return self.tripleContains("linux");
+    }
+
     /// Check if target triple indicates Emscripten (contains "emscripten").
     pub fn isEmscripten(self: TargetConfig) bool {
         return self.tripleContains("emscripten");
@@ -164,11 +174,10 @@ pub fn link(allocator: std.mem.Allocator, io: std.Io, output_obj: []const u8, ex
         for (target_config.lib_paths) |lp| {
             try argv.append(allocator, try std.fmt.allocPrint(allocator, "-L{s}", .{lp}));
         }
-        for (libraries) |lib| {
-            try argv.append(allocator, try std.fmt.allocPrint(allocator, "-l{s}", .{lib}));
-        }
+        // Skip -l flags for Emscripten: libraries like SDL3 are provided via
+        // -sUSE_SDL=3, not -lSDL3. User provides everything via --lflags.
 
-        // Extra linker flags (e.g. -sUSE_SDL=2, -sUSE_WEBGL2=1, --preload-file)
+        // Extra linker flags (e.g. -sUSE_SDL=3, -sUSE_WEBGL2=1, --preload-file)
         for (target_config.extra_link_flags) |flag| {
             try argv.append(allocator, flag);
         }
diff --git a/src/token.zig b/src/token.zig
index 048be2c..87df06c 100644
--- a/src/token.zig
+++ b/src/token.zig
@@ -36,6 +36,7 @@ pub const Tag = enum {
     kw_protocol, // protocol
     kw_impl, // impl
     kw_Self, // Self (in protocol declarations)
+    kw_inline, // inline (compile-time if/for/while)
 
     // Symbols
     colon, // :
@@ -224,6 +225,7 @@ pub const keywords = std.StaticStringMap(Tag).initComptime(.{
     .{ "protocol", .kw_protocol },
     .{ "impl", .kw_impl },
     .{ "Self", .kw_Self },
+    .{ "inline", .kw_inline },
 });
 
 pub fn getKeyword(bytes: []const u8) ?Tag {
diff --git a/src/types.zig b/src/types.zig
index 74ce309..0522d36 100644
--- a/src/types.zig
+++ b/src/types.zig
@@ -24,6 +24,8 @@ pub const Type = union(enum) {
     function_type: FunctionTypeInfo,
     closure_type: ClosureTypeInfo,
     any_type,
+    usize_type,
+    isize_type,
     optional_type: OptionalTypeInfo,
     meta_type: MetaTypeInfo,
     tuple_type: TupleTypeInfo,
@@ -82,7 +84,7 @@ pub const Type = union(enum) {
         return switch (self) {
             .signed => |w| w == other.signed,
             .unsigned => |w| w == other.unsigned,
-            .f32, .f64, .void_type, .boolean, .string_type, .any_type => true,
+            .f32, .f64, .void_type, .boolean, .string_type, .any_type, .usize_type, .isize_type => true,
             .enum_type => |n| std.mem.eql(u8, n, other.enum_type),
             .struct_type => |n| std.mem.eql(u8, n, other.struct_type),
             .union_type => |n| std.mem.eql(u8, n, other.union_type),
@@ -149,12 +151,17 @@ pub const Type = union(enum) {
                 return null;
             },
             'u' => {
+                if (std.mem.eql(u8, name, "usize")) return .usize_type;
                 if (name.len >= 2) {
                     const width = std.fmt.parseInt(u8, name[1..], 10) catch return null;
                     if (width >= 1 and width <= 64) return Type.u(width);
                 }
                 return null;
             },
+            'i' => {
+                if (std.mem.eql(u8, name, "isize")) return .isize_type;
+                return null;
+            },
             'b' => if (std.mem.eql(u8, name, "bool")) .boolean else null,
             'f' => {
                 if (std.mem.eql(u8, name, "f32")) return .f32;
@@ -223,6 +230,8 @@ pub const Type = union(enum) {
             .boolean => "bool",
             .string_type => "string",
             .void_type => "void",
+            .usize_type => "usize",
+            .isize_type => "isize",
             .struct_type => |n| n,
             .enum_type => |n| n,
             .union_type => |n| n,
@@ -544,6 +553,8 @@ pub const Type = union(enum) {
             .string_type => "string",
             .void_type => "void",
             .any_type => "Any",
+            .usize_type => "usize",
+            .isize_type => "isize",
             .enum_type => |name| name,
             .struct_type => |name| name,
             .union_type => |name| name,
diff --git a/tests/expected/50-smoke.txt b/tests/expected/50-smoke.txt
index 49caee0..4568456 100644
--- a/tests/expected/50-smoke.txt
+++ b/tests/expected/50-smoke.txt
@@ -592,4 +592,14 @@ opt-if2: 10.000000
 opt-if3: 10.000000
 opt-if4: 0.000000
 opt-if5: 42.000000
+usize: 42
+isize: -7
+usize+8: 50
+s32->usize: 10
+usize->s64: 42
+=== inline if ===
+64-bit
+not wasm
+known os
+desktop 64-bit
 === DONE ===