Improve platform modules

Author: rtfeldman

src/parse/AST.zig

@@ -236,7 +236,9 @@ pub fn parseDiagnosticToReport(self: *AST, env: *const CommonEnv, diagnostic: Di
         .expected_exposes => "EXPECTED EXPOSES",
         .expected_exposes_close_square => "EXPECTED CLOSING BRACKET",
         .expected_exposes_open_square => "EXPECTED OPENING BRACKET",
-        .expected_imports => "EXPECTED IMPORTS",
+        .expected_packages => "EXPECTED PACKAGES",
+        .expected_packages_close_curly => "EXPECTED CLOSING BRACE",
+        .expected_packages_open_curly => "EXPECTED OPENING BRACE",
         .pattern_unexpected_token => "UNEXPECTED TOKEN IN PATTERN",
         .pattern_list_rest_old_syntax => "BAD LIST REST PATTERN SYNTAX",
         .pattern_unexpected_eof => "UNEXPECTED END OF FILE IN PATTERN",
@@ -304,11 +306,13 @@ pub fn parseDiagnosticToReport(self: *AST, env: *const CommonEnv, diagnostic: Di
             try report.document.addText("For example: ");
             try report.document.addCodeBlock("module [main, add, subtract]");
         },
-        .expected_imports => {
-            try report.document.addReflowingText("Import statements must specify what is being imported.");
+        .expected_packages, .expected_packages_close_curly, .expected_packages_open_curly => {
+            try report.document.addReflowingText("Platform headers must have a ");
+            try report.document.addKeyword("packages");
+            try report.document.addReflowingText(" section that lists package dependencies.");
             try report.document.addLineBreak();
             try report.document.addText("For example: ");
-            try report.document.addCodeBlock("import pf.Stdout exposing [line!]");
+            try report.document.addCodeBlock("packages { base: \"../base/main.roc\" }");
         },
         .pattern_unexpected_token => {
             const token_text = if (diagnostic.region.start != diagnostic.region.end)
@@ -586,7 +590,6 @@ pub const Diagnostic = struct {
         expected_exposes,
         expected_exposes_close_square,
         expected_exposes_open_square,
-        expected_imports,
         expected_package_or_platform_name,
         expected_package_or_platform_colon,
         expected_package_or_platform_string,
@@ -1498,7 +1501,6 @@ pub const Header = union(enum) {
         region: TokenizedRegion,
     },
     platform: struct {
-        // TODO: complete this
         name: Token.Idx,
         requires_rigids: Collection.Idx,
         requires_signatures: TypeAnno.Idx,

src/parse/Parser.zig

@@ -466,7 +466,7 @@ pub fn parsePlatformHeader(self: *Parser) Error!AST.Header.Idx {
     self.expect(.KwPackages) catch {
         return try self.pushMalformed(
             AST.Header.Idx,
-            .expected_imports,
+            .expected_packages,
             self.pos,
         );
     };

test/snapshots/fuzz_crash/fuzz_crash_030.md

@@ -24,7 +24,7 @@ ar,
 ~~~
 # EXPECTED
 PARSE ERROR - fuzz_crash_030.md:8:5:8:6
-PARSE ERROR - fuzz_crash_030.md:12:8:12:9
+EXPECTED CLOSING BRACE - fuzz_crash_030.md:12:8:12:9
 PARSE ERROR - fuzz_crash_030.md:12:9:12:12
 PARSE ERROR - fuzz_crash_030.md:12:12:12:13
 PARSE ERROR - fuzz_crash_030.md:12:13:12:14
@@ -47,9 +47,9 @@ This is an unexpected parsing error. Please check your syntax.
 		  ^
 
 
-**PARSE ERROR**
-A parsing error occurred: `expected_packages_close_curly`
-This is an unexpected parsing error. Please check your syntax.
+**EXPECTED CLOSING BRACE**
+Platform headers must have a `packages` section that lists package dependencies.
+For example:     packages { base: "../base/main.roc" }
 
 **fuzz_crash_030.md:12:8:12:9:**
 ```roc