inferred leading comptime params

LANGUAGE.md

@@ -57,6 +57,7 @@ roadmap and milestone history.
 - demand-monomorphized Brolang and C-ABI functions
 - integer comptime value parameters such as `make_array func($N usize) [N]u8`, specialized by value and omitted from the runtime ABI
 - explicit comptime type parameters such as `max func($T type, a, b T) T`, specialized by type and omitted from the runtime ABI
+- leading comptime type/integer parameters may be omitted when uniquely recoverable from runtime argument types or the immediate expected result; explicit calls remain valid
 - forced typed comptime expressions such as `$sum(1, 2)`, `$Point { x = 1, y = 2 }`, and comptime value blocks such as `${ yield 4 }`
 - comptime execution for bodyful Brolang functions with mutable locals, loops, `defer`, `match`, `try`/`catch`, pointer/slice storage mutation, pointer captures, and calls through comptime-known function values
 - comptime type factories such as `Box func($T type) type { return struct { value T } }`; calls like `Box(i32)` are concrete nominal types and may appear anywhere a type is expected
@@ -94,7 +95,7 @@ roadmap and milestone history.
 - exporting Brolang functions to C and broader target-specific C ABI lowering
 - non-plain C record layouts such as bitfields, packed records, flexible arrays, qualified fields, and C variadic record arguments
 - arenas, pools, build-mode heap policy, and escaping-allocation diagnostics
-- recursive type factories, type reflection, inferred type arguments, and type-producing unions/enums
+- recursive type factories, type reflection, and type-producing unions/enums
 - broader Zig-style pointer/result casts beyond V1 `ptr_cast(T, ptr)`
 - sum-type ABI/layout polish, including dynamic tag-width shrinking, all-void channel collapse, and cross-module global-id determinism
 - backed/C enum composition and must-consume fallible linting

README.md

@@ -177,7 +177,7 @@ Current prototype features:
 - Plain imported C structs/unions, fixed arrays, and C function pointer typedefs, including keyed literals, field access, callbacks, and Apple Silicon by-value ABI lowering
 - Qualified imported globals and functions with package-aware symbol mangling
 - Demand-monomorphized Brolang and C-ABI functions
-- Integer and type comptime parameters (`func($N usize) [N]u8`, `func($T type, value T) T`) specialized by comptime argument
+- Integer and type comptime parameters (`func($N usize) [N]u8`, `func($T type, value T) T`) specialized by explicit or uniquely inferred leading comptime arguments
 - Forced typed comptime expressions (`$sum(1, 2)`, `$Point { x = 1, y = 2 }`) and comptime value blocks (`${ yield 4 }`)
 - Zig-style comptime type factories returning anonymous native structs (`Box func($T type) type`, used as `Box(i32)`)
 - Comptime execution for bodyful Brolang functions with mutable locals, loops, `defer`, `match`, `try`/`catch`, pointer/slice storage mutation, pointer captures, and calls through comptime-known function values

TODO.md

@@ -754,10 +754,41 @@
     zero-count, zero-sized-type, and alignment handling
   - `std/arraylist.ArrayList(T)` exposes `items`, `capacity`, and `allocator`, with fallible
     reserve/append, roughly 1.5x growth from 8, clear-without-free, and reusable deinit
-  - deferred: recursive factories, reflection, inferred type arguments, type-producing
+  - deferred: recursive factories, reflection, type-producing
     unions/enums, pop/insert/remove/shrink/clone container operations
 
-31. threading generic/polymorphic type information everywhere (init, deinit, etc.) might be annoying and verbose. consider whether generic structs could fit nicely to avoid this.
+31. generic container ergonomics (spike completed; no language change)
+  - type factories already provide the important half of generic structs: `ArrayList(T)` is a
+    cached, concrete nominal type whose layout contains `T`; no type information is carried at
+    runtime
+  - the verbosity comes from free functions repeating explicit comptime type arguments
+    (`deinit(i32, &values)`, `append(i32, &values, value)`), not from a missing generic data model
+  - do not add functions inside structs, implicit `Self`, associated lookup, or per-value runtime
+    type metadata for this; those features would add a second namespace/member model without
+    improving layout or specialization
+  - the smallest fitting feature is call-local inference of omitted comptime type arguments:
+    ```
+    values ArrayList(i32) = arraylist.init(mem.c_allocator)
+    defer arraylist.deinit(&values)
+    try arraylist.append(&values, 42)
+    ```
+    `T` comes from the expected result for `init` and from the concrete receiver argument for the
+    other calls
+  - keep functions package-scoped and keep the explicit form valid; this preserves simple name
+    resolution and gives ambiguous calls an escape hatch
+
+31.5. inferred leading comptime parameters (implemented)
+  - a native call may omit its complete leading `$T type` / integer comptime prefix when every
+    value is uniquely recoverable from runtime argument types and/or the immediate expected result
+  - inference structurally matches direct type parameters, pointers/slices/arrays/optionals/
+    fallibles/functions, direct array counts, and canonical generated type-factory provenance;
+    forwarding/non-invertible factories keep the explicit spelling
+  - concrete evidence is exact; contextual numeric constants are weak evidence and are rebuilt with
+    the resolved parameter type before ordinary coercion
+  - calls are all-explicit or all-inferred (no partial prefix omission); unconstrained/conflicting
+    values diagnose with the explicit call as the escape hatch
+  - the existing specialization/HIR/LLVM ABI is unchanged; `std/mem` and `std/arraylist` now use the
+    inferred form where their arguments or result provide enough information
 
 32. disallow arbitrary integer division
   - take inspiration from zig

compiler/checker/checker.odin

@@ -143,6 +143,12 @@ Generated_Type_Entry :: struct {
 	result: types.Type,
 }
 
+Type_Factory_Origin :: struct {
+	result:   types.Type,
+	template: ast.Function_Id,
+	values:   []Comptime_Value,
+}
+
 Checker :: struct {
 	ast_module:           ^ast.Module,
 	diagnostics:          ^source.Diagnostics,
@@ -184,6 +190,7 @@ Checker :: struct {
 	current_comptime_values: []Comptime_Value,
 	type_factories:       [dynamic]Type_Factory_Entry,
 	generated_types:      [dynamic]Generated_Type_Entry,
+	type_factory_origins: [dynamic]Type_Factory_Origin,
 	target:               target.Target,
 	allocator:            mem.Allocator,
 }
@@ -1105,6 +1112,396 @@ valid_call_arity :: proc(function: ast.Function, count: int) -> bool {
 	return count >= len(function.params) if function.variadic else count == len(function.params)
 }
 
+Call_Argument_Mode :: enum u8 {
+	Invalid,
+	Explicit,
+	Inferred,
+}
+
+comptime_prefix_count :: proc(function: ast.Function) -> (int, bool) {
+	count := 0
+	for param in function.params {
+		if param.comptime_value {
+			count += 1
+			continue
+		}
+		break
+	}
+	for param in function.params[count:] {
+		if param.comptime_value {
+			return count, false
+		}
+	}
+	return count, count > 0
+}
+
+call_argument_mode :: proc(function: ast.Function, count: int) -> (Call_Argument_Mode, int) {
+	if valid_call_arity(function, count) {
+		return .Explicit, 0
+	}
+	prefix, inferable := comptime_prefix_count(function)
+	if inferable && !function.c_abi && !function.variadic && count == len(function.params)-prefix {
+		return .Inferred, prefix
+	}
+	return .Invalid, prefix
+}
+
+call_param_index :: proc(mode: Call_Argument_Mode, prefix, source_index: int) -> int {
+	return source_index+prefix if mode == .Inferred else source_index
+}
+
+next_runtime_call_arg :: proc(function: ast.Function, mode: Call_Argument_Mode, prefix, start: int, source_count: int) -> int {
+	index := start
+	for index < source_count {
+		param_index := call_param_index(mode, prefix, index)
+		if param_index >= len(function.params) || !function.params[param_index].comptime_value {
+			break
+		}
+		index += 1
+	}
+	return index
+}
+
+comptime_binding_index :: proc(function: ast.Function, prefix: int, name: symbol.Id) -> (int, bool) {
+	for param, index in function.params[:prefix] {
+		if param.name == name {
+			return index, true
+		}
+	}
+	return -1, false
+}
+
+bind_inferred_comptime :: proc(
+	checker: ^Checker,
+	function: ast.Function,
+	prefix: int,
+	values: []Comptime_Value,
+	bound: []bool,
+	name: symbol.Id,
+	candidate: Comptime_Value,
+	span: source.Span,
+	diagnose: bool,
+) -> bool {
+	index, ok := comptime_binding_index(function, prefix, name)
+	if !ok {
+		return false
+	}
+	value := candidate
+	value.name = name
+	if !bound[index] {
+		values[index] = value
+		bound[index] = true
+		return true
+	}
+	existing := values[index]
+	matches := existing.kind == value.kind
+	if matches {
+		if existing.kind == .Type {
+			matches = types.equal(types.resolve_alias(existing.type, &checker.module.types), types.resolve_alias(value.type, &checker.module.types))
+		} else {
+			matches = existing.value == value.value && types.equal(existing.type, value.type)
+		}
+	}
+	if !matches && diagnose {
+		left := type_label(checker, existing.type) if existing.kind == .Type else fmt.aprintf("%d", existing.value, allocator=checker.allocator)
+		right := type_label(checker, value.type) if value.kind == .Type else fmt.aprintf("%d", value.value, allocator=checker.allocator)
+		source.addf(checker.diagnostics, span, "conflicting inference for comptime parameter '%s': %s and %s", symbol_text(checker, name), left, right)
+		if existing.kind != .Type {
+			delete(left, checker.allocator)
+		}
+		if value.kind != .Type {
+			delete(right, checker.allocator)
+		}
+	}
+	return matches
+}
+
+type_pattern_mentions_comptime :: proc(
+	checker: ^Checker,
+	function: ast.Function,
+	prefix: int,
+	pattern: types.Type,
+	depth := 0,
+) -> bool {
+	if depth > 64 {
+		return false
+	}
+	item, ok := types.node(&checker.module.types, pattern)
+	if !ok {
+		return false
+	}
+	if item.qualifier == 0 && item.name != 0 {
+		if _, found := comptime_binding_index(function, prefix, symbol.Id(item.name)); found {
+			return true
+		}
+	}
+	if item.kind == .Array && item.unresolved_count {
+		expr_id := ast.Expr_Id(item.count_expr)
+		if expr_id != ast.INVALID_EXPR && int(expr_id) < len(checker.ast_module.exprs) {
+			expr := checker.ast_module.exprs[expr_id]
+			if expr.kind == .Name && !symbol.is_valid(expr.qualifier) {
+				if _, found := comptime_binding_index(function, prefix, expr.name); found {
+					return true
+				}
+			}
+		}
+	}
+	if item.kind == .Type_Call {
+		expr_id := ast.Expr_Id(item.count_expr)
+		if expr_id != ast.INVALID_EXPR && int(expr_id) < len(checker.ast_module.exprs) {
+			for arg_id in checker.ast_module.exprs[expr_id].args {
+				if arg_id == ast.INVALID_EXPR || int(arg_id) >= len(checker.ast_module.exprs) {
+					continue
+				}
+				arg := checker.ast_module.exprs[arg_id]
+				if arg.kind == .Name && !symbol.is_valid(arg.qualifier) {
+					if _, found := comptime_binding_index(function, prefix, arg.name); found {
+						return true
+					}
+				}
+			}
+		}
+	}
+	if types.is_valid(item.child) && type_pattern_mentions_comptime(checker, function, prefix, item.child, depth+1) {
+		return true
+	}
+	if types.is_valid(item.extra) && type_pattern_mentions_comptime(checker, function, prefix, item.extra, depth+1) {
+		return true
+	}
+	if item.kind == .Function {
+		for field in types.params_for(&checker.module.types, pattern) {
+			if type_pattern_mentions_comptime(checker, function, prefix, field.type, depth+1) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+match_inferred_type_pattern :: proc(
+	checker: ^Checker,
+	function: ast.Function,
+	prefix: int,
+	pattern, actual: types.Type,
+	values: []Comptime_Value,
+	bound: []bool,
+	span: source.Span,
+	diagnose: bool,
+	depth := 0,
+) -> bool {
+	if depth > 64 || !types.is_valid(actual) {
+		return false
+	}
+	store := &checker.module.types
+	actual_type := types.resolve_alias(actual, store)
+	pattern_item, pattern_ok := types.node(store, pattern)
+	if pattern_ok && pattern_item.qualifier == 0 && pattern_item.name != 0 {
+		name := symbol.Id(pattern_item.name)
+		if index, is_binding := comptime_binding_index(function, prefix, name); is_binding &&
+		   is_comptime_type_param(checker, function.params[index]) {
+			return bind_inferred_comptime(
+				checker, function, prefix, values, bound, name,
+				Comptime_Value{type=actual_type, kind=.Type}, span, diagnose,
+			)
+		}
+	}
+	if !pattern_ok {
+		return types.equal(pattern, actual_type)
+	}
+	if pattern_item.kind == .Type_Call {
+		expr_id := ast.Expr_Id(pattern_item.count_expr)
+		if expr_id == ast.INVALID_EXPR || int(expr_id) >= len(checker.ast_module.exprs) {
+			return false
+		}
+		expr := checker.ast_module.exprs[expr_id]
+		target_pkg, available := expr_package(checker, expr, function.pkg, function.file, true)
+		if !available {
+			return false
+		}
+		template := find_template(checker, expr.name, target_pkg, expr_lookup_file(expr, function.file))
+		origin: Type_Factory_Origin
+		found := false
+		for candidate in checker.type_factory_origins {
+			if candidate.template == template && types.equal(candidate.result, actual_type) {
+				origin = candidate
+				found = true
+				break
+			}
+		}
+		if !found || len(expr.args) != len(origin.values) {
+			return false
+		}
+		matched := true
+		for arg_id, index in expr.args {
+			if arg_id == ast.INVALID_EXPR || int(arg_id) >= len(checker.ast_module.exprs) {
+				matched = false
+				continue
+			}
+			arg := checker.ast_module.exprs[arg_id]
+			if arg.kind == .Name && !symbol.is_valid(arg.qualifier) {
+				if _, is_binding := comptime_binding_index(function, prefix, arg.name); is_binding {
+					matched = bind_inferred_comptime(
+						checker, function, prefix, values, bound, arg.name,
+						origin.values[index], span, diagnose,
+					) && matched
+				}
+			}
+		}
+		return matched
+	}
+	actual_item, actual_ok := types.node(store, actual_type)
+	if !actual_ok || pattern_item.kind != actual_item.kind {
+		resolved := type_from_syntax(checker, pattern, function.pkg, function.file)
+		return types.is_valid(resolved) && types.equal(types.resolve_alias(resolved, store), actual_type)
+	}
+	if pattern_item.many != actual_item.many || pattern_item.has_sentinel != actual_item.has_sentinel ||
+	   pattern_item.has_sentinel && pattern_item.sentinel != actual_item.sentinel {
+		return false
+	}
+	matched := true
+	if pattern_item.kind == .Array {
+		if pattern_item.unresolved_count {
+			count_expr := ast.Expr_Id(pattern_item.count_expr)
+			if count_expr != ast.INVALID_EXPR && int(count_expr) < len(checker.ast_module.exprs) {
+				expr := checker.ast_module.exprs[count_expr]
+				if expr.kind == .Name && !symbol.is_valid(expr.qualifier) {
+					if binding_index, is_binding := comptime_binding_index(function, prefix, expr.name); is_binding &&
+					   !is_comptime_type_param(checker, function.params[binding_index]) {
+						matched = bind_inferred_comptime(
+							checker, function, prefix, values, bound, expr.name,
+							Comptime_Value{type=values[binding_index].type, value=i128(actual_item.count), kind=.Integer},
+							span, diagnose,
+						) && matched
+					}
+				}
+			}
+		} else if pattern_item.count != actual_item.count {
+			matched = false
+		}
+	}
+	if types.is_valid(pattern_item.child) {
+		matched = match_inferred_type_pattern(
+			checker, function, prefix, pattern_item.child, actual_item.child,
+			values, bound, span, diagnose, depth+1,
+		) && matched
+	}
+	if types.is_valid(pattern_item.extra) {
+		matched = match_inferred_type_pattern(
+			checker, function, prefix, pattern_item.extra, actual_item.extra,
+			values, bound, span, diagnose, depth+1,
+		) && matched
+	}
+	if pattern_item.kind == .Function {
+		pattern_params := types.params_for(store, pattern)
+		actual_params := types.params_for(store, actual_type)
+		if len(pattern_params) != len(actual_params) || pattern_item.c_abi != actual_item.c_abi || pattern_item.variadic != actual_item.variadic {
+			return false
+		}
+		for field, index in pattern_params {
+			matched = match_inferred_type_pattern(
+				checker, function, prefix, field.type, actual_params[index].type,
+				values, bound, span, diagnose, depth+1,
+			) && matched
+		}
+	}
+	return matched
+}
+
+infer_call_comptime_values :: proc(
+	checker: ^Checker,
+	function: ast.Function,
+	prefix: int,
+	args: []ast.Expr_Id,
+	actual_args: []types.Type,
+	expected: types.Type,
+	pkg: ast.Package_Id,
+	file: ast.File_Id,
+	diagnose := false,
+) -> ([]Comptime_Value, bool) {
+	values := make([]Comptime_Value, prefix, checker.allocator)
+	bound := make([]bool, prefix, checker.allocator)
+	defer delete(bound, checker.allocator)
+	for param, index in function.params[:prefix] {
+		values[index].name = param.name
+		if is_comptime_type_param(checker, param) {
+			values[index].kind = .Type
+		} else {
+			values[index].kind = .Integer
+			values[index].type = type_from_syntax(checker, param.type, function.pkg, function.file)
+		}
+	}
+	matched := true
+	if is_runtime_type(checker, expected) {
+		if types.is_valid(function.error) && types.kind(expected, &checker.module.types) == .Fallible {
+			matched = match_inferred_type_pattern(
+				checker, function, prefix, function.result,
+				types.fallible_success(expected, &checker.module.types), values, bound,
+				source.Span{}, diagnose,
+			) && matched
+			matched = match_inferred_type_pattern(
+				checker, function, prefix, function.error,
+				types.fallible_error(expected, &checker.module.types), values, bound,
+				source.Span{}, diagnose,
+			) && matched
+		} else if type_pattern_mentions_comptime(checker, function, prefix, function.result) {
+			matched = match_inferred_type_pattern(
+				checker, function, prefix, function.result, expected, values, bound,
+				source.Span{}, diagnose,
+			) && matched
+		}
+	}
+	// Concrete arguments bind first. Numeric constants are contextual and therefore
+	// only contribute their default type after stronger evidence has had a chance.
+	weak_passes := [2]bool{false, true}
+	for weak in weak_passes {
+		for arg_id, source_index in args {
+			param_index := prefix+source_index
+			if param_index >= len(function.params) || param_index >= len(actual_args) {
+				continue
+			}
+			is_weak := is_numeric_constant_expr(checker, arg_id)
+			if is_weak != weak {
+				continue
+			}
+			if !type_pattern_mentions_comptime(checker, function, prefix, function.params[param_index].type) {
+				continue
+			}
+			if weak {
+				if item, ok := types.node(&checker.module.types, function.params[param_index].type); ok &&
+				   item.qualifier == 0 && item.name != 0 {
+					if binding_index, is_binding := comptime_binding_index(function, prefix, symbol.Id(item.name));
+					   is_binding && bound[binding_index] {
+						continue
+					}
+				}
+			}
+			matched = match_inferred_type_pattern(
+				checker, function, prefix, function.params[param_index].type,
+				actual_args[param_index], values, bound,
+				checker.ast_module.exprs[arg_id].span, diagnose,
+			) && matched
+		}
+	}
+	for param, index in function.params[:prefix] {
+		if bound[index] {
+			continue
+		}
+		matched = false
+		if diagnose {
+			source.addf(
+				checker.diagnostics, param.span,
+				"cannot infer comptime parameter '%s'; pass it explicitly",
+				symbol_text(checker, param.name),
+			)
+		}
+	}
+	if !matched {
+		delete(values, checker.allocator)
+		return nil, false
+	}
+	return values, true
+}
+
 call_arg_expected :: proc(checker: ^Checker, function: ast.Function, index: int) -> types.Type {
 	if index < 0 || index >= len(function.params) {
 		return types.INVALID
@@ -1112,6 +1509,14 @@ call_arg_expected :: proc(checker: ^Checker, function: ast.Function, index: int)
 	if is_comptime_type_param(checker, function.params[index]) {
 		return types.INVALID
 	}
+	for param in function.params {
+		if !param.comptime_value {
+			continue
+		}
+		if _, ok := current_comptime_value(checker, param.name); !ok {
+			return types.INVALID
+		}
+	}
 	declared := type_from_syntax(checker, function.params[index].type, function.pkg, function.file)
 	// A `float` param defaults to f64 so an integer-literal argument builds as a
 	// float constant (e.g. `f(3)` -> 3.0), mirroring `pi float = 3` for locals.
@@ -1273,6 +1678,31 @@ resolve_type_factory_call :: proc(checker: ^Checker, expr_id: ast.Expr_Id, pkg:
 	ct_state_destroy(&state)
 	checker.type_factories[entry_index].result = result
 	checker.type_factories[entry_index].resolving = false
+	if types.is_valid(result) {
+		generated := false
+		for entry in checker.generated_types {
+			if types.equal(entry.result, result) {
+				generated = true
+				break
+			}
+		}
+		if generated {
+			has_origin := false
+			for origin in checker.type_factory_origins {
+				if types.equal(origin.result, result) {
+					has_origin = true
+					break
+				}
+			}
+			if !has_origin {
+				append(&checker.type_factory_origins, Type_Factory_Origin{
+					result=result,
+					template=template,
+					values=clone_comptime_values(values, checker.allocator),
+				})
+			}
+		}
+	}
 	return result
 }
 
@@ -1631,7 +2061,10 @@ validate_declarations :: proc(checker: ^Checker) {
 		locals: [dynamic]symbol.Id
 		locals.allocator = checker.allocator
 		for param in function.params {
-			param_type := type_from_syntax(checker, param.type, function.pkg, function.file)
+			param_type := types.INVALID
+			if param.comptime_value || !has_comptime {
+				param_type = type_from_syntax(checker, param.type, function.pkg, function.file)
+			}
 			if param.comptime_value {
 				if function.c_abi {
 					checker.template_diagnostics[function_id] = source.add(
@@ -2078,9 +2511,12 @@ mark_spec_demanded :: proc(checker: ^Checker, id: Spec_Id, stack: ^[dynamic]Spec
 
 Infer_Frame :: struct {
 	expr:      ast.Expr_Id,
+	expected:  types.Type,
 	stage:     u8,
 	left:      types.Type,
 	arg_index: int,
+	arg_mode:  Call_Argument_Mode,
+	prefix:    int,
 	args:      []types.Type,
 	template:  ast.Function_Id,
 }
@@ -2093,11 +2529,12 @@ infer_nested_expr :: proc(
 	file: ast.File_Id,
 	demanded: ^[dynamic]Spec_Id,
 	local_types: []types.Type = nil,
+	expected := types.INVALID,
 ) -> types.Type {
 	outer := checker.infer_stack
 	checker.infer_stack = nil
 	checker.infer_stack.allocator = checker.allocator
-	result := infer_expr(checker, expr_id, locals, pkg, file, demanded, local_types)
+	result := infer_expr(checker, expr_id, locals, pkg, file, demanded, local_types, expected)
 	delete(checker.infer_stack)
 	checker.infer_stack = outer
 	return result
@@ -2111,6 +2548,7 @@ infer_compound_expr :: proc(
 	file: ast.File_Id,
 	demanded: ^[dynamic]Spec_Id,
 	local_types: []types.Type = nil,
+	expected := types.INVALID,
 ) -> types.Type {
 	store := &checker.module.types
 	#partial switch expr.kind {
@@ -2224,10 +2662,12 @@ infer_compound_expr :: proc(
 		_ = infer_nested_expr(checker, expr.right, locals, pkg, file, demanded, local_types)
 		return types.child_type(value, store) if types.is_optional(value, store) else types.INVALID
 	case .Try:
-		value := infer_nested_expr(checker, expr.left, locals, pkg, file, demanded, local_types)
+		left_expected := expected if checker.ast_module.exprs[expr.left].kind == .Call else types.INVALID
+		value := infer_nested_expr(checker, expr.left, locals, pkg, file, demanded, local_types, left_expected)
 		return types.fallible_success(value, store) if types.kind(value, store) == .Fallible else types.INVALID
 	case .Catch:
-		value := infer_nested_expr(checker, expr.left, locals, pkg, file, demanded, local_types)
+		left_expected := expected if checker.ast_module.exprs[expr.left].kind == .Call else types.INVALID
+		value := infer_nested_expr(checker, expr.left, locals, pkg, file, demanded, local_types, left_expected)
 		success := types.fallible_success(value, store)
 		error_type := types.fallible_error(value, store)
 		if expr.right != ast.INVALID_EXPR {
@@ -2273,6 +2713,7 @@ infer_expr :: proc(
 	file := ast.File_Id(0),
 	demanded: ^[dynamic]Spec_Id = nil,
 	local_types: []types.Type = nil,
+	expected := types.INVALID,
 ) -> types.Type {
 	stack := checker.infer_stack
 	clear_dynamic_array(&stack)
@@ -2283,7 +2724,7 @@ infer_expr :: proc(
 		clear_dynamic_array(&stack)
 		checker.infer_stack = stack
 	}
-	append(&stack, Infer_Frame{expr=expr_id, template=ast.INVALID_FUNCTION})
+	append(&stack, Infer_Frame{expr=expr_id, expected=expected, template=ast.INVALID_FUNCTION})
 	last := types.INVALID
 
 	for len(stack) > 0 {
@@ -2330,7 +2771,7 @@ infer_expr :: proc(
 			case .String, .Array, .None, .Undefined, .Address, .Deref, .Index, .Slice,
 			     .Field, .Unwrap, .Orelse, .Try, .Catch, .Struct_Literal, .Keyed, .Enum_Literal, .Cast,
 			     .Comptime, .Bool, .Not, .Eq, .Ne, .Lt, .Le, .Gt, .Ge, .And, .Or, .Range:
-				last = infer_compound_expr(checker, expr, locals, pkg, file, demanded, local_types)
+				last = infer_compound_expr(checker, expr, locals, pkg, file, demanded, local_types, frame.expected)
 				_ = pop(&stack)
 			case .Function_Literal:
 				template := ast.Function_Id(u32(expr.integer))
@@ -2559,11 +3000,26 @@ infer_expr :: proc(
 					_ = pop(&stack)
 					continue
 				}
+				function := checker.ast_module.functions[template]
+				mode, prefix := call_argument_mode(function, len(expr.args))
+				if mode == .Invalid {
+					last = types.INVALID
+					_ = pop(&stack)
+					continue
+				}
 				stack[frame_index].template = template
-				stack[frame_index].args = make([]types.Type, len(expr.args), checker.allocator)
+				stack[frame_index].arg_mode = mode
+				stack[frame_index].prefix = prefix
+				stack[frame_index].args = make([]types.Type, len(function.params), checker.allocator)
+				stack[frame_index].arg_index = next_runtime_call_arg(function, mode, prefix, 0, len(expr.args))
 				stack[frame_index].stage = 3
-				if len(expr.args) > 0 {
-					append(&stack, Infer_Frame{expr=expr.args[0], template=ast.INVALID_FUNCTION})
+				if stack[frame_index].arg_index < len(expr.args) {
+					param_index := call_param_index(mode, prefix, stack[frame_index].arg_index)
+					arg_expected := call_arg_expected(checker, function, param_index)
+					if !is_runtime_type(checker, arg_expected) {
+						arg_expected = types.INVALID
+					}
+					append(&stack, Infer_Frame{expr=expr.args[stack[frame_index].arg_index], expected=arg_expected, template=ast.INVALID_FUNCTION})
 				}
 			}
 			continue
@@ -2616,37 +3072,62 @@ infer_expr :: proc(
 		}
 		if frame.stage == 3 {
 			if frame.arg_index < len(expr.args) {
-				stack[frame_index].args[frame.arg_index] = last
-				stack[frame_index].arg_index += 1
-				if frame.arg_index+1 < len(expr.args) {
-					append(&stack, Infer_Frame{expr=expr.args[frame.arg_index+1], template=ast.INVALID_FUNCTION})
+				param_index := call_param_index(frame.arg_mode, frame.prefix, frame.arg_index)
+				if param_index < len(stack[frame_index].args) {
+					stack[frame_index].args[param_index] = last
+				}
+				next := next_runtime_call_arg(
+					checker.ast_module.functions[frame.template], frame.arg_mode, frame.prefix,
+					frame.arg_index+1, len(expr.args),
+				)
+				stack[frame_index].arg_index = next
+				if next < len(expr.args) {
+					next_param := call_param_index(frame.arg_mode, frame.prefix, next)
+					arg_expected := call_arg_expected(checker, checker.ast_module.functions[frame.template], next_param)
+					if !is_runtime_type(checker, arg_expected) {
+						arg_expected = types.INVALID
+					}
+					append(&stack, Infer_Frame{expr=expr.args[next], expected=arg_expected, template=ast.INVALID_FUNCTION})
 					continue
 				}
 			}
 			function := checker.ast_module.functions[frame.template]
-			// A bare-name argument passed to a concrete (non-constraint) parameter pushes
-			// that parameter type back onto the argument's slot, so an open constant adopts
-			// it (e.g. `take_u16(a)` resolves `a` to u16). Constraint params have no single
-			// type to demand; the callee's result flowing back is milestone 14.5.
-			for arg_index in 0..<len(expr.args) {
-				record_demand(checker, expr.args[arg_index], call_arg_expected(checker, function, arg_index), locals, local_types, pkg, file)
-			}
 			// Deferred defaulting leaves an undemanded open constant typeless; give such an
 			// argument its default so the call can still monomorphize (the default feeds only
 			// the spec arg vector, not a demand).
-			for arg_index in 0..<len(expr.args) {
-				if !is_runtime_type(checker, stack[frame_index].args[arg_index]) {
-					fallback := open_const_default_type(checker, expr.args[arg_index], locals, pkg, file)
+			for source_index in 0..<len(expr.args) {
+				param_index := call_param_index(frame.arg_mode, frame.prefix, source_index)
+				if param_index < len(stack[frame_index].args) && !is_runtime_type(checker, stack[frame_index].args[param_index]) {
+					fallback := open_const_default_type(checker, expr.args[source_index], locals, pkg, file)
 					if is_runtime_type(checker, fallback) {
-						stack[frame_index].args[arg_index] = fallback
+						stack[frame_index].args[param_index] = fallback
 					}
 				}
 			}
-			comptime_values, comptime_ok := collect_comptime_values(checker, function, expr.args, pkg, file)
+			comptime_values: []Comptime_Value
+			comptime_ok := false
+			if frame.arg_mode == .Inferred {
+				comptime_values, comptime_ok = infer_call_comptime_values(
+					checker, function, frame.prefix, expr.args, stack[frame_index].args,
+					frame.expected, pkg, file,
+				)
+			} else {
+				comptime_values, comptime_ok = collect_comptime_values(checker, function, expr.args, pkg, file)
+			}
 			defer delete(comptime_values, checker.allocator)
-			if valid_call_arity(function, len(expr.args)) &&
-			   comptime_ok &&
+			if comptime_ok &&
 			   can_specialize(checker, function, stack[frame_index].args, comptime_values) {
+				previous_comptime := checker.current_comptime_values
+				checker.current_comptime_values = comptime_values
+				for source_index in 0..<len(expr.args) {
+					param_index := call_param_index(frame.arg_mode, frame.prefix, source_index)
+					if param_index >= len(function.params) || function.params[param_index].comptime_value {
+						continue
+					}
+					demand := call_arg_expected(checker, function, param_index)
+					record_demand(checker, expr.args[source_index], demand, locals, local_types, pkg, file)
+				}
+				checker.current_comptime_values = previous_comptime
 				spec := INVALID_SPEC
 				if demanded == nil {
 					spec = ensure_spec(checker, frame.template, stack[frame_index].args, comptime_values)
@@ -2657,7 +3138,10 @@ infer_expr :: proc(
 				if spec != INVALID_SPEC {
 					last = checker.specs[spec].result
 				} else {
+					previous_comptime := checker.current_comptime_values
+					checker.current_comptime_values = comptime_values
 					declared := function_channel_type(checker, function)
+					checker.current_comptime_values = previous_comptime
 					last = declared if is_runtime_type(checker, declared) || types.is_void(declared) else types.INVALID
 				}
 			} else {
@@ -2810,7 +3294,8 @@ infer_statements :: proc(
 			declared_local := resolve_inferred_array(checker, type_from_syntax(checker, statement.type, pkg, file), statement.expr)
 			value_type := types.INVALID
 			if !is_undefined_expr(checker, statement.expr) {
-				value_type = infer_expr(checker, statement.expr, locals^[:], pkg, file, demanded, local_types)
+				expected := declared_local if is_runtime_type(checker, declared_local) else types.INVALID
+				value_type = infer_expr(checker, statement.expr, locals^[:], pkg, file, demanded, local_types, expected)
 				declared_local = resolve_inferred_array_from_type(checker, declared_local, value_type)
 			}
 			if is_runtime_type(checker, declared_local) && !has_inferred_array_count(checker, declared_local) {
@@ -2863,14 +3348,24 @@ infer_statements :: proc(
 				infer_statements(checker, statement.body, locals, local_types, pkg, file, demanded, result, result_hint)
 				continue
 			}
-			value_type := infer_expr(checker, statement.expr, locals^[:], pkg, file, demanded, local_types)
+			expected_assignment := types.INVALID
+			if statement.target != ast.INVALID_EXPR {
+				expected_assignment = infer_expr(checker, statement.target, locals^[:], pkg, file, demanded, local_types)
+			} else if statement.name != checker.sink_symbol {
+				if local_index, ok := find_infer_local_index(locals^[:], statement.name); ok {
+					expected_assignment = locals^[local_index].type
+				} else if global := find_global(checker, statement.name, pkg, file); global != ast.INVALID_GLOBAL {
+					expected_assignment = checker.global_types[global]
+				}
+			}
+			value_type := infer_expr(checker, statement.expr, locals^[:], pkg, file, demanded, local_types, expected_assignment)
 			// Only push the target's type back onto a bare-name RHS (e.g. `x += speed`):
 			// pushing through an arithmetic RHS would feed the target's (often provisional)
 			// type onto open-constant operands and poison their family. Operands of an
 			// arithmetic RHS resolve from their own authoritative uses.
 			rhs_is_arith := is_arith_kind(checker.ast_module.exprs[statement.expr].kind)
 			if statement.target != ast.INVALID_EXPR {
-				target_type := infer_expr(checker, statement.target, locals^[:], pkg, file, demanded, local_types)
+				target_type := expected_assignment
 				target_expr := checker.ast_module.exprs[statement.target]
 				if target_expr.kind == .Name && !symbol.is_valid(target_expr.qualifier) {
 					if local_index, ok := find_infer_local_index(locals^[:], target_expr.name); ok &&
@@ -2903,7 +3398,7 @@ infer_statements :: proc(
 			}
 		case .Return:
 			if statement.expr != ast.INVALID_EXPR {
-				returned := infer_expr(checker, statement.expr, locals^[:], pkg, file, demanded, local_types)
+				returned := infer_expr(checker, statement.expr, locals^[:], pkg, file, demanded, local_types, result_hint)
 				if is_runtime_type(checker, result_hint) {
 					_ = record_demand_shallow(checker, statement.expr, result_hint, locals^[:], local_types, pkg, file)
 					expr := checker.ast_module.exprs[statement.expr]
@@ -3505,12 +4000,13 @@ infer_all :: proc(checker: ^Checker) {
 			if global.external {
 				continue
 			}
-			inferred := infer_expr(checker, global.expr, nil, global.pkg, global.file)
 			declared := resolve_inferred_array(
 				checker,
 				type_from_syntax(checker, global.type, global.pkg, global.file),
 				global.expr,
 			)
+			expected := declared if is_runtime_type(checker, declared) else types.INVALID
+			inferred := infer_expr(checker, global.expr, nil, global.pkg, global.file, expected=expected)
 			if resolved := resolve_inferred_array_from_type(checker, declared, inferred);
 			   resolved != declared {
 				if !types.equal(checker.global_types[index], resolved) {
@@ -3991,19 +4487,13 @@ Build_Expr_Frame :: struct {
 	stage:      u8,
 	left:       hir.Expr_Id,
 	arg_index:  int,
+	arg_mode:   Call_Argument_Mode,
+	prefix:     int,
 	built_args: []hir.Expr_Id,
 	arg_types:  []types.Type,
 	template:   ast.Function_Id,
 }
 
-next_built_template_arg :: proc(checker: ^Checker, function: ast.Function, start: int) -> int {
-	index := start
-	for index < len(function.params) && is_comptime_type_param(checker, function.params[index]) {
-		index += 1
-	}
-	return index
-}
-
 hir_location_writable :: proc(checker: ^Checker, expr_id: hir.Expr_Id, locals: []Build_Local) -> bool {
 	if expr_id == hir.INVALID_EXPR || int(expr_id) >= len(checker.module.exprs) {
 		return false
@@ -4714,7 +5204,8 @@ build_compound_expr :: proc(
 			target=hir.INVALID_REF, diagnostic=source.INVALID_DIAGNOSTIC,
 		})
 	case .Try:
-		channel := build_nested_expr(checker, expr.left, locals, global_reads, calls, types.INVALID, pkg, file)
+		left_expected := expected if checker.ast_module.exprs[expr.left].kind == .Call else types.INVALID
+		channel := build_nested_expr(checker, expr.left, locals, global_reads, calls, left_expected, pkg, file)
 		channel_type := checker.module.exprs[channel].type
 		success := types.fallible_success(channel_type, store)
 		if !types.is_valid(success) {
@@ -4747,7 +5238,8 @@ build_compound_expr :: proc(
 			diagnostic=source.INVALID_DIAGNOSTIC,
 		})
 	case .Catch:
-		channel := build_nested_expr(checker, expr.left, locals, global_reads, calls, types.INVALID, pkg, file)
+		left_expected := expected if checker.ast_module.exprs[expr.left].kind == .Call else types.INVALID
+		channel := build_nested_expr(checker, expr.left, locals, global_reads, calls, left_expected, pkg, file)
 		channel_type := checker.module.exprs[channel].type
 		success := types.fallible_success(channel_type, store)
 		if !types.is_valid(success) {
@@ -5448,9 +5940,20 @@ build_expr :: proc(
 					_ = pop(&stack)
 					continue
 				}
-				if !valid_call_arity(function, len(expr.args)) {
+				mode, prefix := call_argument_mode(function, len(expr.args))
+				if mode == .Invalid {
 					message := "function '%s' expects at least %d arguments, got %d" if function.variadic else
 					           "function '%s' expects %d arguments, got %d"
+					if inferred_prefix, inferable := comptime_prefix_count(function); inferable && !function.c_abi && !function.variadic {
+						id := source.addf(
+							checker.diagnostics, expr.span,
+							"function '%s' expects %d arguments with explicit comptime parameters or %d with inferred comptime parameters, got %d",
+							symbol_text(checker, expr.name), len(function.params), len(function.params)-inferred_prefix, len(expr.args),
+						)
+						last = invalid_hir_expr(checker, expr.span, id)
+						_ = pop(&stack)
+						continue
+					}
 					id := source.addf(
 						checker.diagnostics,
 						expr.span,
@@ -5464,15 +5967,18 @@ build_expr :: proc(
 					continue
 				}
 				stack[frame_index].template = template
+				stack[frame_index].arg_mode = mode
+				stack[frame_index].prefix = prefix
 				stack[frame_index].built_args = make([]hir.Expr_Id, len(expr.args), checker.allocator)
-				stack[frame_index].arg_types = make([]types.Type, len(expr.args), checker.allocator)
+				stack[frame_index].arg_types = make([]types.Type, len(function.params), checker.allocator)
 				for &arg in stack[frame_index].built_args {
 					arg = hir.INVALID_EXPR
 				}
-				stack[frame_index].arg_index = next_built_template_arg(checker, function, 0)
+				stack[frame_index].arg_index = next_runtime_call_arg(function, mode, prefix, 0, len(expr.args))
 				stack[frame_index].stage = 3
 				if stack[frame_index].arg_index < len(expr.args) {
-					arg_expected := call_arg_expected(checker, function, stack[frame_index].arg_index)
+					param_index := call_param_index(mode, prefix, stack[frame_index].arg_index)
+					arg_expected := call_arg_expected(checker, function, param_index)
 					if !is_runtime_type(checker, arg_expected) {
 						arg_expected = types.INVALID
 					}
@@ -5527,11 +6033,18 @@ build_expr :: proc(
 		if frame.stage == 3 {
 			if frame.arg_index < len(expr.args) {
 				stack[frame_index].built_args[frame.arg_index] = last
-				stack[frame_index].arg_types[frame.arg_index] = checker.module.exprs[last].type
-				next := next_built_template_arg(checker, checker.ast_module.functions[frame.template], frame.arg_index+1)
+				param_index := call_param_index(frame.arg_mode, frame.prefix, frame.arg_index)
+				if param_index < len(stack[frame_index].arg_types) {
+					stack[frame_index].arg_types[param_index] = checker.module.exprs[last].type
+				}
+				next := next_runtime_call_arg(
+					checker.ast_module.functions[frame.template], frame.arg_mode, frame.prefix,
+					frame.arg_index+1, len(expr.args),
+				)
 				stack[frame_index].arg_index = next
 				if next < len(expr.args) {
-					arg_expected := call_arg_expected(checker, checker.ast_module.functions[frame.template], next)
+					next_param := call_param_index(frame.arg_mode, frame.prefix, next)
+					arg_expected := call_arg_expected(checker, checker.ast_module.functions[frame.template], next_param)
 					if !is_runtime_type(checker, arg_expected) {
 						arg_expected = types.INVALID
 					}
@@ -5540,8 +6053,39 @@ build_expr :: proc(
 				}
 			}
 			function := checker.ast_module.functions[frame.template]
-			comptime_values, comptime_ok := collect_comptime_values(checker, function, expr.args, pkg, file, diagnose=true)
+			comptime_values: []Comptime_Value
+			comptime_ok := false
+			if frame.arg_mode == .Inferred {
+				comptime_values, comptime_ok = infer_call_comptime_values(
+					checker, function, frame.prefix, expr.args, stack[frame_index].arg_types,
+					frame.expected, pkg, file, diagnose=true,
+				)
+			} else {
+				comptime_values, comptime_ok = collect_comptime_values(checker, function, expr.args, pkg, file, diagnose=true)
+			}
 			defer delete(comptime_values, checker.allocator)
+			if comptime_ok {
+				previous_comptime := checker.current_comptime_values
+				checker.current_comptime_values = comptime_values
+				for source_index in 0..<len(expr.args) {
+					param_index := call_param_index(frame.arg_mode, frame.prefix, source_index)
+					if param_index >= len(function.params) || function.params[param_index].comptime_value ||
+					   !is_numeric_constant_expr(checker, expr.args[source_index]) {
+						continue
+					}
+					expected_arg := call_arg_expected(checker, function, param_index)
+					if !is_runtime_type(checker, expected_arg) {
+						continue
+					}
+					rebuilt := build_nested_expr(
+						checker, expr.args[source_index], locals, global_reads, calls,
+						expected_arg, pkg, file,
+					)
+					stack[frame_index].built_args[source_index] = rebuilt
+					stack[frame_index].arg_types[param_index] = checker.module.exprs[rebuilt].type
+				}
+				checker.current_comptime_values = previous_comptime
+			}
 			arg_violation := source.INVALID_DIAGNOSTIC
 			if comptime_ok {
 				previous_comptime := checker.current_comptime_values
@@ -5604,10 +6148,11 @@ build_expr :: proc(
 			runtime_arg_count := runtime_count + max(0, len(source_args)-len(function.params))
 			runtime_args := make([]hir.Expr_Id, runtime_arg_count, checker.allocator)
 			runtime_index := 0
-			for param, source_index in function.params {
+			for param, param_index in function.params {
 				if param.comptime_value {
 					continue
 				}
+				source_index := param_index if frame.arg_mode == .Explicit else param_index-frame.prefix
 				arg := source_args[source_index]
 				runtime_args[runtime_index] = coerce_expr(
 					checker,
@@ -8977,6 +9522,7 @@ check :: proc(
 	checker.anon_globals.allocator = allocator
 	checker.type_factories.allocator = allocator
 	checker.generated_types.allocator = allocator
+	checker.type_factory_origins.allocator = allocator
 	build_symbol_indexes(&checker)
 	checker.global_types = make([]types.Type, len(ast_module.globals), allocator)
 	checker.global_demands = make([]types.Type, len(ast_module.globals), allocator)
@@ -9026,8 +9572,12 @@ check :: proc(
 		for entry in checker.generated_types {
 			delete(entry.values, allocator)
 		}
+		for origin in checker.type_factory_origins {
+			delete(origin.values, allocator)
+		}
 		delete(checker.type_factories)
 		delete(checker.generated_types)
+		delete(checker.type_factory_origins)
 	}
 
 	for function, index in ast_module.functions {

compiler_tests.odin

@@ -2573,8 +2573,8 @@ main func() void {
 	for diagnostic in diagnostics.items {
 		message := diagnostic.message
 		found_runtime_arg = found_runtime_arg || strings.contains(message, "must be a compile-time integer expression")
-		found_missing = found_missing || strings.contains(message, "expects 1 arguments, got 0")
-		found_extra = found_extra || strings.contains(message, "expects 1 arguments, got 2")
+		found_missing = found_missing || strings.contains(message, "cannot infer comptime parameter 'N'")
+		found_extra = found_extra || strings.contains(message, "expects 1 arguments with explicit comptime parameters or 0 with inferred comptime parameters, got 2")
 		found_negative = found_negative || strings.contains(message, "integer constant -1 does not fit in usize")
 		found_range = found_range || strings.contains(message, "integer constant 300 does not fit in u8")
 		found_bad_type = found_bad_type || strings.contains(message, "requires a concrete integer type")
@@ -2592,6 +2592,64 @@ main func() void {
 	testing.expect(t, found_address)
 }
 
+@(test)
+inferred_comptime_params_diagnose_ambiguous_calls :: proc(t: ^testing.T) {
+	text := `Ignored func($T type) type {
+	return i32
+}
+Box func($T type) type {
+	return struct { value T }
+}
+BoxAlias func($T type) type {
+	return Box(T)
+}
+conflict func($T type, left, right T) T { return left }
+unknown func($T type) T { value T = undefined; return value }
+partial func($T type, $N usize, value T) T { return value }
+use_ignored func($T type, value Ignored(T)) i32 { return value }
+use_alias func($T type, value BoxAlias(T)) T { return value.value }
+main func() void {
+	a i32 :: 1
+	b u32 :: 2
+	_ = conflict(a, b)
+	_ = unknown()
+	_ = partial(i32, a)
+	_ = use_ignored(a)
+	box Box(i32) :: Box(i32) { value = 1 }
+	_ = use_alias(box)
+}
+`
+	source_file := source.Source{path="test.bro", text=text}
+	diagnostics := source.init_diagnostics(&source_file)
+	defer source.destroy_diagnostics(&diagnostics)
+	symbols := symbol.init_table()
+	defer symbol.destroy_table(&symbols)
+	stream := lexer.lex(&source_file, &diagnostics, &symbols)
+	defer delete(stream.items)
+	ast_module := parser.parse(&stream, &source_file, &diagnostics)
+	defer ast.destroy_module(&ast_module)
+	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
+	defer hir.destroy_module(&hir_module)
+
+	found_conflict := false
+	found_unknown := false
+	found_partial := false
+	unrecoverable := 0
+	for diagnostic in diagnostics.items {
+		message := diagnostic.message
+		found_conflict = found_conflict || strings.contains(message, "conflicting inference for comptime parameter 'T': i32 and u32")
+		found_unknown = found_unknown || strings.contains(message, "cannot infer comptime parameter 'T'")
+		found_partial = found_partial || strings.contains(message, "expects 3 arguments with explicit comptime parameters or 1 with inferred comptime parameters, got 2")
+		if strings.contains(message, "cannot infer comptime parameter 'T'") {
+			unrecoverable += 1
+		}
+	}
+	testing.expect(t, found_conflict)
+	testing.expect(t, found_unknown)
+	testing.expect(t, found_partial)
+	testing.expect(t, unrecoverable >= 3)
+}
+
 @(test)
 comptime_type_params_specialize_by_type_and_omit_runtime_args :: proc(t: ^testing.T) {
 	text := `Point :: struct {

examples/programs/arraylist/main.bro

@@ -25,13 +25,13 @@ _fail_allocator mem.Allocator :: mem.Allocator {
 _noop func() void {}
 
 run func() i32 ! mem.AllocError {
-	values arraylist.ArrayList(i32) = arraylist.init(i32, mem.c_allocator)
-	defer arraylist.deinit(i32, &values)
+	values arraylist.ArrayList(i32) = arraylist.init(mem.c_allocator)
+	defer arraylist.deinit(&values)
 	if (values.items.len != 0 or values.capacity != 0) return 1
 
 	i usize = 0
 	while i < 20 : i += 1 {
-		arraylist.append(i32, &values, i32(i)) catch |_| {
+		arraylist.append(&values, i32(i)) catch |_| {
 			return .out_of_memory
 		}
 	}
@@ -40,34 +40,34 @@ run func() i32 ! mem.AllocError {
 	values.items[3] = 33
 	if (values.items[3] != 33) return 4
 
-	arraylist.reserve(i32, &values, 50) catch |_| {
+	arraylist.reserve(&values, 50) catch |_| {
 		return .out_of_memory
 	}
 	if (values.capacity < 50 or values.items.len != 20 or values.items[19] != 19) return 5
 	capacity usize :: values.capacity
-	arraylist.clear(i32, &values)
+	arraylist.clear(&values)
 	if (values.items.len != 0 or values.capacity != capacity) return 6
-	arraylist.append(i32, &values, 7) catch |_| {
+	arraylist.append(&values, 7) catch |_| {
 		return .out_of_memory
 	}
 	if (values.items.len != 1 or values.items[0] != 7 or values.capacity != capacity) return 7
 
-	empty_values arraylist.ArrayList([0]u8) = arraylist.init([0]u8, mem.c_allocator)
-	defer arraylist.deinit([0]u8, &empty_values)
+	empty_values arraylist.ArrayList([0]u8) = arraylist.init(mem.c_allocator)
+	defer arraylist.deinit(&empty_values)
 	zero [0]u8 :: []
-	arraylist.append([0]u8, &empty_values, zero) catch |_| {
+	arraylist.append(&empty_values, zero) catch |_| {
 		return .out_of_memory
 	}
 	if (empty_values.items.len != 1) return 8
 
 	failed arraylist.ArrayList(i32) = arraylist.init(i32, _fail_allocator)
 	failed_as_expected bool = false
-	arraylist.append(i32, &failed, 1) catch |_| {
+	arraylist.append(&failed, 1) catch |_| {
 		failed_as_expected = true
 		yield _noop()
 	}
 	if (failed_as_expected == false or failed.items.len != 0 or failed.capacity != 0) return 9
-	arraylist.deinit(i32, &failed)
+	arraylist.deinit(&failed)
 
 	return 0
 }

examples/programs/comptime_type_params/main.bro

@@ -19,10 +19,37 @@ buffer func($T type, $N usize, value T) [N]T {
 	return data
 }
 
+zero func($T type) T {
+	value T = undefined
+	return value
+}
+
+array_len func($T type, $N usize, values [N]T) usize {
+	return values.len
+}
+
+Fixed func($T type, $N usize) type {
+	return struct {
+		values [N]T
+	}
+}
+
+fixed_len func($T type, $N usize, value @Fixed(T, N)) usize {
+	return value.values.len
+}
+
+take_i32 func(value i32) i32 {
+	return value
+}
+
+return_zero func() i32 {
+	return zero()
+}
+
 main func() i32 {
 	a i32 :: 42
 	b i32 :: 27
-	if max(i32, a, b) != 42 {
+	if max(a, b) != 42 {
 		return 1
 	}
 
@@ -33,14 +60,32 @@ main func() i32 {
 	}
 
 	p Point :: Point { x = 11 }
-	q Point :: id(Point, p)
+	q Point :: id(p)
 	if q.x != 11 {
 		return 3
 	}
 
-	bytes [_]u8 :: buffer(u8, 4, small_a)
+	bytes [4]u8 :: buffer(small_a)
 	if bytes.len != 4 {
 		return 4
 	}
+	if array_len(bytes) != 4 {
+		return 5
+	}
+	zero_value i32 :: zero()
+	_ = zero_value
+	literal :: id(7)
+	if literal != 7 {
+		return 6
+	}
+	fixed Fixed(u8, 3) :: Fixed(u8, 3) { values = [1, 2, 3] }
+	if fixed_len(&fixed) != 3 {
+		return 7
+	}
+	assigned i32 = 1
+	assigned = zero()
+	_ = assigned
+	_ = take_i32(zero())
+	_ = return_zero()
 	return 0
 }

examples/programs/mem_allocator/task_list.bro

@@ -23,7 +23,7 @@ task_list_init func(allocator mem.Allocator) TaskList {
 alloc_i32s func(allocator mem.Allocator, count usize) ?[]mut i32 {
 	fallback [1]mut i32 = undefined
 	failed bool = false
-	values []mut i32 = mem.alloc(i32, allocator, count) catch |_| {
+	values []mut i32 = mem.alloc(allocator, count) catch |_| {
 		failed = true
 		yield (&fallback).ptr[..0]
 	}
@@ -33,7 +33,7 @@ alloc_i32s func(allocator mem.Allocator, count usize) ?[]mut i32 {
 
 free_i32s func(allocator mem.Allocator, values ?[]mut i32) void {
 	if values |slice| {
-		mem.free(i32, allocator, slice)
+		mem.free(allocator, slice)
 	}
 }
 

examples/programs/mem_allocator/typed_alloc.bro

@@ -49,12 +49,12 @@ typed_allocator_test func() i32 {
 
 	i32_fallback [1]mut i32 = undefined
 	empty_failed bool = false
-	empty []mut i32 = mem.alloc(i32, first_allocator, 0) catch |_| {
+	empty []mut i32 = mem.alloc(first_allocator, 0) catch |_| {
 		empty_failed = true
 		yield (&i32_fallback).ptr[..0]
 	}
 	if (empty_failed or empty.len != 0 or first_calls[0] != 3) return 34
-	mem.free(i32, first_allocator, empty)
+	mem.free(first_allocator, empty)
 	if (first_calls[0] != 3) return 33
 
 	zero_sized_fallback [1]mut [0]u8 = undefined
@@ -70,7 +70,7 @@ typed_allocator_test func() i32 {
 
 	u64_fallback [1]mut u64 = undefined
 	overflow_fallback_failed bool = false
-	overflow_fallback []mut u64 = mem.alloc(u64, first_allocator, 0) catch |_| {
+	overflow_fallback []mut u64 = mem.alloc(first_allocator, 0) catch |_| {
 		overflow_fallback_failed = true
 		yield (&u64_fallback).ptr[..0]
 	}
@@ -83,20 +83,20 @@ typed_allocator_test func() i32 {
 	if (overflow_failed == false or first_calls[0] != 3) return 40
 
 	typed_failed bool = false
-	typed []mut i32 = mem.alloc(i32, mem.c_allocator, 4) catch |_| {
+	typed []mut i32 = mem.alloc(mem.c_allocator, 4) catch |_| {
 		typed_failed = true
 		yield (&i32_fallback).ptr[..0]
 	}
 	if (typed_failed) return 38
-	defer mem.free(i32, mem.c_allocator, typed)
+	defer mem.free(mem.c_allocator, typed)
 	typed[0] = 10
 	typed[3] = 20
 	if (typed[0] + typed[3] != 30) return 39
-	typed = mem.realloc(i32, mem.c_allocator, typed, 8) catch |_| {
+	typed = mem.realloc(mem.c_allocator, typed, 8) catch |_| {
 		return 41
 	}
 	if (typed.len != 8 or typed[0] != 10 or typed[3] != 20) return 42
-	typed = mem.realloc(i32, mem.c_allocator, typed, 2) catch |_| {
+	typed = mem.realloc(mem.c_allocator, typed, 2) catch |_| {
 		return 43
 	}
 	if (typed.len != 2 or typed[0] != 10) return 44

std/arraylist/arraylist.bro

@@ -18,7 +18,7 @@ init func($T type, allocator mem.Allocator) ArrayList(T) {
 
 deinit func($T type, list @mut ArrayList(T)) void {
 	allocation []mut T :: list.items.ptr[..list.capacity]
-	mem.free(T, list.allocator, allocation)
+	mem.free(list.allocator, allocation)
 	list.items = mem.empty(T)
 	list.capacity = 0
 }
@@ -43,7 +43,7 @@ reserve func($T type, list @mut ArrayList(T), minimum_capacity usize) void ! mem
 
 	length usize :: list.items.len
 	allocation []mut T :: list.items.ptr[..list.capacity]
-	grown []mut T :: mem.realloc(T, list.allocator, allocation, new_capacity) catch |_| {
+	grown []mut T :: mem.realloc(list.allocator, allocation, new_capacity) catch |_| {
 		return .out_of_memory
 	}
 	list.items = grown.ptr[..length]
@@ -56,7 +56,7 @@ append func($T type, list @mut ArrayList(T), value T) void ! mem.AllocError {
 	if length == max_value(usize) {
 		return .out_of_memory
 	}
-	try reserve(T, list, length + 1)
+	try reserve(list, length + 1)
 	list.items = list.items.ptr[..length + 1]
 	list.items[length] = value
 	return _

std/mem/mem.bro

@@ -64,7 +64,7 @@ realloc func($T type, allocator Allocator, memory []mut T, new_count usize) []mu
 		return memory
 	}
 	if new_count == 0 {
-		free(T, allocator, memory)
+		free(allocator, memory)
 		return _empty_slice(T, 0)
 	}