analysis: create err ctx buffer on init()

- do better error message for resolveGlobalType

examples/hello.ry

@@ -8,7 +8,7 @@ fn f() i32 {
 }
 
 fn f2() i32 {
-    return f() + 2;
+    return f.awoo;
 }
 
 enum B {

src/analysis.zig

@@ -16,8 +16,13 @@ pub const TypeSolver = struct {
     err_tok: ?Token = null,
     hadError: bool = false,
 
-    pub fn init(allocator: *std.mem.Allocator) TypeSolver {
-        return TypeSolver{ .allocator = allocator };
+    err_ctx_buffer: []u8,
+
+    pub fn init(allocator: *std.mem.Allocator) !TypeSolver {
+        return TypeSolver{
+            .allocator = allocator,
+            .err_ctx_buffer = try allocator.alloc(u8, 512),
+        };
     }
 
     fn setErrContext(self: *@This(), comptime fmt: ?[]const u8, args: ...) void {
@@ -26,9 +31,11 @@ pub const TypeSolver = struct {
             return;
         }
 
-        // TODO allocate buffer on init() and use it
-        var buf = self.allocator.alloc(u8, 256) catch unreachable;
-        self.err_ctx = std.fmt.bufPrint(buf, fmt.?, args) catch unreachable;
+        self.err_ctx = std.fmt.bufPrint(
+            self.err_ctx_buffer,
+            fmt.?,
+            args,
+        ) catch unreachable;
     }
 
     fn setErrToken(self: *@This(), tok: ?Token) void {
@@ -38,7 +45,7 @@ pub const TypeSolver = struct {
     fn doError(self: *@This(), comptime fmt: []const u8, args: ...) void {
         self.hadError = true;
 
-        std.debug.warn("type error");
+        std.debug.warn("analysis error");
         if (self.err_tok) |tok| {
             std.debug.warn(" at line {}", tok.line);
         }
@@ -53,35 +60,41 @@ pub const TypeSolver = struct {
     }
 
     /// Resolve a type in global scope
+    /// Properly resolves composite (currently opaque) types to structs/enums.
     fn resolveGlobalType(
         self: *@This(),
         ctx: *comp.CompilationContext,
         identifier: []const u8,
     ) ?SymbolUnderlyingType {
-        // assume the identifier references a builtin
+        // first, we assume the identifier is for a simple type
+        // if we fail (and this always returns OpaqueType as a fallback),
+        // we take it and find something in global scope
         var typ = ctx.solveType(identifier);
 
         switch (typ) {
             .OpaqueType => |val| {
-                // solve for opaque so it isnt opaque
                 var sym = ctx.symbol_table.get(val);
-                if (sym != null)
+
+                if (sym == null) {
+                    self.doError("Unknown type: '{}'", val);
+                    return null;
+                }
+
                 return switch (sym.?.value) {
                     .Struct => SymbolUnderlyingType{ .Struct = val },
                     .Enum => SymbolUnderlyingType{ .Enum = val },
 
+                    // TODO name resolution
+
                     else => blk: {
                         self.doError(
-                                "expected struct or enum for type '{}', got {}",
+                            "expected struct or enum for '{}', got {}",
                             val,
-                                sym,
+                            @tagName(comp.SymbolType(sym.?.value)),
                         );
                         break :blk null;
                     },
                 };
-
-                self.doError("Unknown type: '{}'", val);
-                return null;
             },
 
             else => return typ,
@@ -102,6 +115,7 @@ pub const TypeSolver = struct {
         }
     }
 
+    /// Compare if the given type names are equal.
     fn compositeIdentifierEqual(
         self: *@This(),
         typ_enum: comp.SymbolUnderlyingTypeEnum,

src/main.zig

@@ -50,7 +50,7 @@ pub fn run(allocator: *std.mem.Allocator, slice: []const u8) !Result {
     std.debug.warn("parse tree\n");
     printer.printNode(root, 0);
 
-    var solver = analysis.TypeSolver.init(allocator);
+    var solver = try analysis.TypeSolver.init(allocator);
     var ctx = try solver.pass(root);
 
     std.debug.warn("symbol table\n");